bims-proteo Biomed News
on Proteostasis
Issue of 2026–10–25
53 papers selected by
Eric Chevet, INSERM
  1. Molecular triage and isoform protection safeguard ubiquitin chain editing on DNA.
  2. A USP28-TM9SF3-Golgiphagy axis maintains glycosylation homeostasis and promotes breast cancer progression.
  3. Genetic dissection of rapid proteolysis identifies TXNDC15 as a key factor of ERAD and lipid homeostasis.
  4. HAP40 functions as a proteostasis regulator by controlling huntingtin interactions and its release into the extracellular space.
  5. Multimodal substrate recruitment enables CTLHMKLN1 E3 ligase to target acetylated N-, C-, and internal degrons.
  6. The endoplasmic reticulum autophagy receptor TEX264 drives epidermal differentiation and is dysregulated in Darier disease.
  7. Proteome-wide C-degron activity profiling connects conditional regulation of the CTLH E3 ligase complex to ribosome biogenesis.
  8. Molecular drivers of cotranslational protein assembly in bacteria.
  9. The conserved NUS-1/DHDDS-1 complex links N-glycosylation to lipid and lysosomal homeostasis in C. elegans.
  10. Proximity biotinylation at the host-Shigella interface reveals UFMylation as an antibacterial pathway.
  11. A role for eIF5A in translational control of stress-inducible proteins in multiple myeloma cell lines.
  12. C-RAF Sequence-Encoded Cooperativity Hotspots for 14-3-3/C-RAF Molecular Glues.
  13. Systematic optimization and characterization of the MidTAC platform for targeted protein degradation.
  14. The unfolded protein response as a proteotoxic stress-resolution circuit: branch-selective signaling and failed resolution in environmental immunotoxicity.
  15. Proteomic atlas of T cell exhaustion defines proteostatic collapse.
  16. ClC-7 links PIKfyve inhibition to Rab-dependent LRRK2 activity at lysosomes.
  17. Improving PROTAC-Mediated Degradation in Mouse Models: BRD9 as a Case Study.
  18. Atypical E3 ligase HOIL1 promotes MDA5 signaling and ester-linked ubiquitination of LGP2.
  19. Selective USP32 inhibition reveals endosomal ubiquitin signaling and enables cell-permeable activity-based probes.
  20. BRAP maintains SEC24D stability to regulate ER stress and promote cervical adenocarcinoma progression.
  21. GRP75-dependent SIMPA mediates inter-organellar quality control.
  22. The Long Splice Variant of Ribosomal Protein S24 Protects Cells from Stress and Is Induced by AMPK-ULK1-Regulated Autophagy Independent of mTORC1.
  23. Receptor-Specific ER-Phagy in Neurodegenerative Diseases: Molecular Mechanisms and Emerging Therapeutic Opportunities.
  24. PhagoID: Quantitative in situ proximity labeling defines the proteomes of bead- and microbe-containing phagosome lumina across species, maturation, and immune activation.
  25. SSH1 knockdown increases autophagosome formation through ATG9A recruitment and promotes tau protein degradation.
  26. Aptamer-Based Targeted Protein Degradation: Mechanistic Principles, Delivery Strategies, and Translational Opportunities.
  27. Ribo-seq rRNA reads reveal co-predicted signatures of ribosome heterogeneity and collisions.
  28. Chaperonopathies as Disorders of Disorder: The Role of Intrinsically Disordered Regions in Proteostasis Dysfunction.
  29. Chemically Induced Proximity for Targeted Protein O-GlcNAcylation.
  30. Cold activates a BH2 metabolic network promoting longevity and proteostasis.
  31. Comparative analysis of photocatalytic, enzymatic, and chemical approaches to identify canonical and noncanonical surfaceomes.
  32. Structure of Blm10:13S proteasome intermediate reveals parallel assembly pathways for the proteasome core particle.
  33. Discovery of a Protein Kinase R-like Endoplasmic Reticulum Kinase (PERK) Inhibitor Suitable for Clinical Progression.
  34. Landscape of Endocytic Effectors for Extracellular Targeted Protein Degradation.
  35. Programmable Enhancement of IRES-Mediated Translation via RNA-Guided eIF4G Recruitment.
  36. Structural basis for start codon selection by eIF5-mimic proteins.
  37. Protein disulphide isomerase protects against ALS/FTD phenotypes associated with cyclin F in zebrafish and cellular models.
  38. A common germline 3' UTR variant controls DDIT4 translation efficiency and stress responses in cancer cells.
  39. A lipoprotein-biomimetic nanoplatform for oncogenic KRAS mutation-specific lysosome-targeting protein degradation.
  40. Hsc70-Mediated Targeting Chimeras for Targeted Protein Degradation via Chaperone-Mediated Autophagy.
  41. Stella safeguards proteostasis via regulating UBE2D3 translation in the maternal-to-zygotic transition.
  42. Single-Atom Modification Enables Reversal of Degradation Selectivity between NSD2 and GSPT1.
  43. Deubiquitinase-Targeting Chimera (DUBTAC)-Enhanced Mammalian Expression System for Efficient Recombinant Protein Expression.
  44. Metformin improves mitophagy-related pathways and mitochondrial-lysosomal homeostasis in chromosome 21 trisomic fibroblasts.
  45. Proteasome inhibition bidirectionally regulates ferroptosis sensitivity.
  46. mRNA Structure Regulates Translation at Every Step.
  47. CHK1 phosphorylates TRIM28 at Ser473 to drive NLRP3 inflammasome assembly and inflammatory responses.
  48. First demonstration of benzosultam CRBN ligand-mediated PROTACs for BTK and BRD4 degradation.
  49. A 2-in-1 Strategy for the Discovery of Compact HDAC8 Protac Degraders.
  50. Development of Isoform-Selective GRP78 Inhibitors from a Direct-to-Biology Strategy.
  51. Swollen lysosomes grab Rabs for a CASM-free route to LRRK2 activation.
  52. Artificial Initiation Codons and Engineered Initiator tRNAs Enable N-Terminal Noncanonical Amino Acid Incorporation in Cell-Free Translation Systems While Retaining Native Methionine Incorporation.
  53. A host-virus arms race over FAM134B in African swine fever virus infection.
  1. Cell Rep. 2026 Oct 16. pii: S2211-1247(26)01216-7. [Epub ahead of print]45(10): 118137
    Molecular triage and isoform protection safeguard ubiquitin chain editing on DNA.
    Xianzhen Zhou, Martin Attwood, Alexandra McStea, Benjamin Foster, Ian Gibbs-Seymour.
      In an accompanying study, we identify the RPA-ZUP1 complex as a ubiquitin chain-editing machine that promotes removal of RPA from ssDNA. Because loss of ZUP1 causes pathological RPA trapping on ssDNA, cells must preserve a functional RPA-ZUP1 pool to sustain RPA turnover. How this homeostasis is achieved is unknown. Here, we show that ZUP1 is subject to ubiquitin-dependent fate control. ZUP1 ubiquitination promotes recruitment of p97/VCP and ATXN3, defining a molecular triage pathway that protects ZUP1 from premature proteasomal degradation. Opposing this, the E3 ligases UBR5 and HUWE1 define a degradative branch that limits ZUP1 abundance, with HUWE1 restricting its accumulation on damaged chromatin. We further show that cells express a naturally occurring ZUP1 isoform resistant to efficient ubiquitination and turnover, suggesting that isoform diversity provides a protected pool of chain-editing activity. Together, these findings define a homeostatic system that preserves ZUP1 while limiting its persistence on damaged chromatin.
    Keywords:  ATXN3; CP: molecular biology; DNA repair; HUWE1; RPA; UBR5; Ubiquitin; VCP; ZUP1; adipocyte; circadian rhythms; metabolism; organ communication; p97; systems biology; unfolded protein response
    DOI:  https://doi.org/10.1016/j.celrep.2026.118137
  2. EMBO J. 2026 Oct 19.
    A USP28-TM9SF3-Golgiphagy axis maintains glycosylation homeostasis and promotes breast cancer progression.
    Jiaxin Xu, Yang Cai, Yuting Zhang, Jiejie Yang, Yixian Cui.
      Selective autophagy of the Golgi apparatus (Golgiphagy) is essential for Golgi quality control, yet its regulation and physiological functions remain poorly understood. Here, we identify the deubiquitinase USP28 as an upstream regulator of the Golgiphagy receptor TM9SF3. USP28 removes degradative K48-linked ubiquitin chains from TM9SF3, preventing its proteasomal degradation and sustaining Golgiphagy under nutrient and Golgi stresses. CRM1-dependent nuclear export enables the stress-induced translocation of USP28 to the Golgi, where it stabilizes TM9SF3, promoting Golgi fragmentation and autophagic clearance. Loss of USP28 or TM9SF3 impairs Golgiphagy, disrupts glycosylation fidelity, and inhibits breast cancer cell proliferation. Proteomic and functional analyses identify the glycosyltransferase MGAT5 as a selective TM9SF3-dependent Golgiphagy cargo, revealing how this pathway maintains glycosylation homeostasis. In syngeneic tumor models, USP28 knockout or pharmacological inhibition reduces TM9SF3 abundance, compromises Golgiphagy, perturbs glycosylation, and markedly suppresses tumor growth-effects restored by wild-type but not LC3-binding-deficient TM9SF3. Together, these findings reveal a USP28-TM9SF3-Golgiphagy axis that couples ubiquitin signaling to Golgi glycosylation control and represents a therapeutically targetable pathway for breast cancer.
    DOI:  https://doi.org/10.1038/s44318-026-00947-1
  3. Cell Chem Biol. 2026 Oct 22. pii: S2451-9456(26)00370-3. [Epub ahead of print]
    Genetic dissection of rapid proteolysis identifies TXNDC15 as a key factor of ERAD and lipid homeostasis.
    Yuyang Liu, Michelle Yinfei Yaochai, Shanshan Liu, Hanan Alwaseem, Kıvanç Birsoy.
      Biological systems face a constantly changing environment and must swiftly respond to stimuli; yet how cells sense and adapt to environmental and physiological cues is incompletely understood. Short-lived proteins can be rapidly induced upon perturbation, enabling swift activation of adaptive cellular responses. Here, leveraging genome-wide data on protein-transcript correlation, we systematically searched for rapid proteolysis substrates whose abundance reflects the activity of the underlying proteolytic machinery. Focusing on the candidate substrate ABHD2, we performed CRISPR-based genetic screens to dissect its degradation. These screens identified TXNDC15 as an essential factor in MARCHF6-mediated ER-associated protein degradation (ERAD). Mechanistically, TXNDC15 supports substrate exit and degradation from the ER via a catalysis-independent mechanism. Loss of TXNDC15 remodels the ER proteome and lipid homeostasis. Together, our work defines a missing component of ERAD and provides a generalizable strategy to decode post-translational regulatory circuits.
    Keywords:  ABHD2; ERAD; MARCHF6; TXNDC15; endoplasmic-reticulum-associated protein degradation; lipid metabolism; post translational regulation; protein degradation
    DOI:  https://doi.org/10.1016/j.chembiol.2026.09.021
  4. Proc Natl Acad Sci U S A. 2026 Oct 27. 123(43): e2611301123
    HAP40 functions as a proteostasis regulator by controlling huntingtin interactions and its release into the extracellular space.
    Eduardo Silva Ramos, Annett Boeddrich, Christian Haenig, Philipp Trepte, Orchid Ammar, Christopher Secker, Oliver Popp, Andranik Ivanov, Stephanie Beetz, Leonard Roth, Roxane M Papawassiliou, Luisanna C Hernandez Jeppesen, Theo Wallenfang, Brandon Keith, Rachel J Harding, Franziska Schindler, Tomas Koudelka, Nadine Scharek, Martina Zenkner, Nancy Neuendorf, Sabrina Golusik, Philipp Mertins, Ilaria Piazza, Sigrid Schnoegl, Erich E Wanker.
      Huntingtin-associated protein 40 (HAP40) forms a stable protein complex with huntingtin (HTT). Its cellular function and how HAP40 loss influences mutant HTT (mHTT) abundance and pathobiology are currently unclear. Here, using diverse cellular models and omics methods, we demonstrate that HAP40 is an obligate interaction partner of HTT and through its binding controls HTT interactions and the abundance of HTT-associated proteins, indicating that it functions as a HTT interaction regulatory unit. Also, loss of HAP40 in mHTT-expressing striatal cells impairs autophagic protein degradation and triggers transcriptional activation of the CLEAR network, demonstrating that it functions as a proteostasis regulator that acts on quality control pathways. Finally, mHTT-expressing cells lacking HAP40 showed increased secretion of a ~205 kDa mHTT fragment through an endoplasmic reticulum (ER)/Golgi-associated route, indicating that striatal cells reduce intracellular mHTT-induced proteotoxicity through activation of secretory pathways. Together, these results establish HAP40 as a critical proteostasis regulator that through controlling HTT interactions maintains cellular homeostasis.
    Keywords:  HAP40; Huntington’s disease; autophagy; mutant HTT; proteostasis
    DOI:  https://doi.org/10.1073/pnas.2611301123
  5. Nat Commun. 2026 10 17. pii: 10877. [Epub ahead of print]17(1):
    Multimodal substrate recruitment enables CTLHMKLN1 E3 ligase to target acetylated N-, C-, and internal degrons.
    Sara Sepic, Karthik V Gottemukkala, Jiale Du, Samuel A Maiwald, Jakub Chrustowicz, Eleftheria C Papadopoulou, Luca J Stier, Susanne von Gronau, Brenda A Schulman.
      The GID/CTLH family of E3 ubiquitin ligases employs several substrate receptor subunits that recruit distinct degrons, but the substrate recognition mechanisms of the CTLHMKLN1 assembly have largely remained elusive. Here, we reconstitute CTLHMKLN1-dependent ubiquitylation of three biochemically distinct substrates - MKLN1 itself, ZMYND19, and FAM72A-recruited UNG2, and determine cryo-EM structures of each substrate bound to MKLN1. The structures reveal how MKLN1's discoidin and Kelch β-propeller domains engage substrates through multivalent contacts. MKLN1 recruits itself through discoidin-Kelch interactions between MKLN1 dimers, forming an assembly that competes with other substrates. ZMYND19 and FAM72A each bind to MKLN1 through loops engaging the discoidin trench domain while their C-terminal Arg residues engage the MKLN1 Kelch central channel, identifying MKLN1 as an Arg/C-degron receptor. The acetylated N-terminus of UNG2 is positioned within a Y-shaped tunnel of FAM72A, defining an adaptor-mediated Ac/N-degron recognition mechanism. Thus, our data reveal how combinatorial deployment of MKLN1 discoidin and Kelch domains enable a single receptor subunit to recognize a diverse substrate repertoire, adding to a complex picture of degron recognition across the GID/CTLH family.
    DOI:  https://doi.org/10.1038/s41467-026-78311-4
  6. JCI Insight. 2026 Oct 22. pii: e196831. [Epub ahead of print]
    The endoplasmic reticulum autophagy receptor TEX264 drives epidermal differentiation and is dysregulated in Darier disease.
    Christopher J Johnson, Afua Tiwaa, Arti Parihar, Edwin Antonio, Brooke D Lorenz, Reeteka Kudallur, Aaron Ramonett, Anthony Coon, Mrinal K Sarkar, Johann Gudjonsson, Cory L Simpson.
      Differentiating keratinocytes break down their organelles and nuclei to become the compacted cornified layers of the epidermal barrier in a poorly understood catabolic process. Live confocal imaging of stratified human organotypic epidermis revealed endoplasmic reticulum (ER) fragmentation and lysosomal engulfment in the cornifying layers, where we found up-regulation of TEX264, a receptor that mediates selective autophagy of the ER (reticulophagy). TEX264 expression was increased by ER stress, which caused precocious cornification of organotypic epidermis. In undifferentiated keratinocytes, ectopic TEX264 was sufficient to induce ER fragments, while in highly differentiated keratinocytes, it accelerated ER elimination and nuclear shrinkage; these effects were abolished by mutating the LC3 interacting region required for its autophagic function. Knockout of TEX264 or inhibiting its activation disrupted the maturation of organotypic cultures, pointing to a critical role for reticulophagy in cornification. Finally, in patient biopsies and an organotypic model of Darier disease, a genetic cornification disorder linked to ER dysfunction, we found increased TEX264 in areas of premature cornification (dyskeratosis). Our results identified TEX264 as a key driver of late-stage epidermal differentiation and led us to propose a model of cornification in which keratinocytes activate selective autophagy receptors to orchestrate orderly organelle elimination during cutaneous barrier formation.
    Keywords:  Autophagy; Cell biology; Dermatology; Genetic diseases; Skin
    DOI:  https://doi.org/10.1172/jci.insight.196831
  7. Mol Cell. 2026 Oct 20. pii: S1097-2765(26)00679-9. [Epub ahead of print]
    Proteome-wide C-degron activity profiling connects conditional regulation of the CTLH E3 ligase complex to ribosome biogenesis.
    Drew W Grant, Shengjiang Tan, Dylan E Ramage, Mamie Z Li, Ying Di, Iva A Tchasovnikarova, Michael P Weekes, Stephen J Elledge, Alan J Warren, Richard T Timms.
      Many E3 ubiquitin ligases recognize degrons located at protein termini, but the paucity of bona fide substrates of N-degron and C-degron pathways hampers our understanding of their physiological significance. Devising an expression screening strategy to assess the effect of C-terminal "capping" on the stability of thousands of human proteins, we systematically identify substrates harboring C-degrons. Interrogating one leading candidate, ZMYND19, we characterize a C-degron pathway governed via the C-terminal to LisH (CTLH) E3 ligase complex subunit Muskelin. Cell-to-cell variability in ZMYND19 stability uncovered conditional regulation, with CTLH-mediated degradation impaired by TNF-α stimulation but enhanced by mTOR inhibition. Parallel genetic and proteomic screens identified angio-associated migratory protein (AAMP) and apoptosis-enhancing nuclease (AEN) as additional substrates of the CTLHMuskelin C-degron pathway, leading us to define an essential role for AAMP in ribosome maturation through chaperone activity toward uL16. Altogether, these data define a C-degron pathway connecting conditional regulation of the CTLH E3 ligase complex to ribosome biogenesis.
    Keywords:  AAMP; AEN; C-degron; CTLH E3 ligase complex; RPL10; ZMYND19; protein degradation; ribosome biogenesis; uL16; ubiquitin-proteasome system
    DOI:  https://doi.org/10.1016/j.molcel.2026.09.036
  8. Proc Natl Acad Sci U S A. 2026 Oct 27. 123(43): e2608997123
    Molecular drivers of cotranslational protein assembly in bacteria.
    Jaro L Schmitt, Josef J Auburger, Florian Wruck, Jiří Koubek, Sander J Tans, Bernd Bukau, Günter Kramer.
      Protein complexes are pivotal to all major cellular processes. Translation-coupled complex assembly is ubiquitous in eukaryotes, but its molecular basis and prevalence in bacteria remain poorly understood. Here, we combine ribosome profiling and single-molecule optical tweezers to establish principles governing cotranslational assembly of four structurally diverse complexes in Escherichia coli. We reveal how heterotetramers form cotranslationally via hierarchical assembly pathways, with initial heterodimer formation priming the assembly of higher-order oligomers through a topology-dependent organization of homomeric and heteromeric interfaces. Co-post assembly, defined as interaction between nascent and fully synthesized subunits, initiates when dimerization domains are completely exposed at the ribosome. The assembly order is predominantly unidirectional and matches the operon gene order, with upstream-encoded subunits being synthesized first, and then engaging downstream nascent partner subunits. The co-post assembly efficiency depends both on the native operon structure and the ribosome-associated chaperone trigger factor, which binds emerging oligomerization domains and whose dissociation marks the onset of partner subunit engagement. The handover from chaperone engagement to cotranslational assembly is mediated by nascent chain folding. Finally, we show that co-post assembly provides a fitness advantage. Together, these findings reveal how genome organization and chaperone-assisted folding coordinate cotranslational assembly to promote efficient complex biogenesis and cellular fitness in bacteria.
    Keywords:  cotranslational protein assembly; molecular chaperones; nascent chain folding; operon structure; trigger factor
    DOI:  https://doi.org/10.1073/pnas.2608997123
  9. Cell Rep. 2026 Oct 19. pii: S2211-1247(26)01257-X. [Epub ahead of print]45(11): 118178
    The conserved NUS-1/DHDDS-1 complex links N-glycosylation to lipid and lysosomal homeostasis in C. elegans.
    Meixi Gong, Wentao Zhao, Yilin Du, Lingfan Zhu, Yile Zhai, Yuxiao Xie, Chen Liu, Wenfei Li, Pei Zhao, Zhe Zhang.
      N-glycosylation is essential for proteome integrity, yet the systemic roles of the cis-prenyltransferase (cis-PT) complex remain poorly defined. Using Caenorhabditis elegans, we demonstrate that this complex is a dual regulator of global lipid and lysosomal homeostasis. Mechanistically, NUS-1 physically associates with the core oligosaccharyltransferase (OST) complex to coordinate N-glycan transfer. Loss of NUS-1/DHDDS-1 triggers endoplasmic reticulum stress, lysosomal collapse, and systemic lipopenia. This lipid defect arises from impaired N-glycosylation of the SREBP cleavage-activating protein (SCAP). cis-PT deficiency causes unglycosylated SCAP to undergo massive degradation and absolute physical entrapment within the ER, preventing SREBP nuclear translocation and downstream lipid synthesis. Furthermore, pathogenic mutations cause dysfunction through distinct molecular mechanisms: pocket integrity disruption or catalytic impairment. These findings uncover an essential crosstalk between protein glycosylation and global lipid metabolism, providing a mechanistic framework for understanding the systemic pathophysiology of congenital disorders of glycosylation (CDG).
    Keywords:  CP: metabolism; CP: molecular biology; Caenorhabditis elegans; ER stress; N-glycosylation; NUS-1/DHDDS-1; SREBP; cis-prenyltransferase complex; lipid homeostasis; lysosomal homeostasis
    DOI:  https://doi.org/10.1016/j.celrep.2026.118178
  10. Nat Commun. 2026 09 17. pii: 10930. [Epub ahead of print]17(1):
    Proximity biotinylation at the host-Shigella interface reveals UFMylation as an antibacterial pathway.
    Ana T López-Jiménez, Fabien Théry, Kathryn Wright, Hannah Painter, Shelby T Hoffmeister, Lucas Jarche, Jeremy Benjamin, Gerbrand J van der Heden van Noort, Dominik Brokatzky, Margarida C Gomes, Sydney L Miles, Damián Lobato-Márquez, Eva-Maria Frickel, John Rohde, Jonathan N Pruneda, Francis Impens, Serge Mostowy.
      Host cells contest invasion by intracellular bacterial pathogens with multiple strategies that recognise and/or damage the bacterial surface. To identify host defence factors targeted to intracellular bacteria, we developed a proximity biotinylation approach coupled to quantitative mass spectrometry that maps the host-bacterial interface during infection. Using this method, we discovered that intracellular Shigella and Salmonella become targeted by UFM1-protein ligase 1 (UFL1), an E3 ligase that catalyses the covalent attachment of Ubiquitin-fold modifier 1 (UFM1) to target substrates in a process called UFMylation. Shigella antagonises UFMylation in a dual manner: first, using its lipopolysaccharide to shield from UFL1 recruitment; second, preventing UFM1 decoration by the bacterial effector IpaH9.8. Absence of UFMylation leads to an increase of bacterial burden in human cells and zebrafish larvae. Contrary to ubiquitylation, the protective role of UFMylation is independent of autophagy. Altogether, our proximity mapping of the host-bacterial interface identifies UFMylation as an ancient antibacterial pathway and holds great promise to reveal other cell-autonomous immunity mechanisms.
    DOI:  https://doi.org/10.1038/s41467-026-77860-y
  11. Mol Oncol. 2026 Oct 21.
    A role for eIF5A in translational control of stress-inducible proteins in multiple myeloma cell lines.
    Demi Both, Ingrid A M Derks, Raphaël Vanleyssem, Marine Leclercq, Najla El Hachem, Pierre Close, Eric Eldering, Marco Vincent Haselager.
      Impaired protein folding in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR), which can induce apoptosis during prolonged ER stress. ER stress is therapeutically targeted in plasma cell malignancies, such as multiple myeloma (MM), but these treatments remain noncurative, and UPR signaling in B-cell malignancies is incompletely understood. A targeted CRISPR-Cas9 screen in RPMI-8226 cells exposed to thapsigargin identified known ER stress regulators (XBP1, IRE1, and calreticulin) and the translation factor eIF5A (eukaryotic translation initiation factor 5A), whose role in ER stress remains unclear. Competition assays showed that eIF5A depletion is detrimental under basal conditions but confers a proliferation advantage during thapsigargin treatment. Inducible EIF5A knockouts confirmed reduced sensitivity specifically to thapsigargin, loss of eIF5A had no or sensitizing effects on cell death induced by other ER stress drugs. Polysome profiling revealed that not general translation, but the translation of specific mRNA transcripts coding for UPR components and apoptotic proteins was affected by eIF5A depletion. Correspondingly, EIF5A KO cells showed reduced thapsigargin-induced UPR activation. In conclusion, these findings indicate that loss of eIF5A alters the stress response in MM cells.
    Keywords:  ER stress; UPR; apoptosis; eIF5A; multiple myeloma; translation
    DOI:  https://doi.org/10.1002/1878-0261.70328
  12. J Med Chem. 2026 Oct 08. 69(19): 22869-22881
    C-RAF Sequence-Encoded Cooperativity Hotspots for 14-3-3/C-RAF Molecular Glues.
    Marloes A M Pennings, Gwenn-Aël A M Lauffer, Markella Konstantinidou, Rens M J M de Vries, Christian Ottmann, Michelle R Arkin, Luc Brunsveld.
      14-3-3 Proteins are hub proteins with an extensive interactome of phosphorylated client proteins, making them attractive targets for molecular glues (MGs) that stabilize specific 14-3-3/client protein complexes. However, selectively stabilizing individual 14-3-3 protein-protein interactions (PPIs) remains a key challenge for effectively drugging the 14-3-3 interactome. Here, we systematically investigated the sequence-encoded determinants underlying selective stabilization of the 14-3-3/C-RAF complex by covalent MGs. Using stepwise C-terminal peptide sequence extension, alanine scanning, and MG activity analysis on a large 14-3-3 peptide interactome panel, we demonstrate that residues beyond the canonical +1 and +2 positions contribute to cooperative ternary complex formation. The C-RAF +4Val and +6Met residues promote stabilization by an MG through sequence-dependent conformational arrangements that position the peptide backbone and enable the +6Met side chain to wrap around the MG, thereby reducing ternary complex dissociation. These findings provide general principles for the rational design of selective cooperative MGs targeting hub protein PPIs.
    Keywords:  14-3-3; kinetics; molecular glues; protein−protein interactions; selectivity; structural biology
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c02049
  13. Acta Pharmacol Sin. 2026 Oct 19.
    Systematic optimization and characterization of the MidTAC platform for targeted protein degradation.
    Yu-Bing Han, Si-Hong Zhong, Ming-Zhi Wang, Zhen-Qian Fu, Yu-Tong Tu, Jia Li, Yu-Bo Zhou.
      Biological proteolysis-targeting chimeras (BioPROTACs), which employ peptide or protein-based targeting ligands to recruit endogenous degradation machinery, offer a promising strategy to expand the scope of targeted protein degradation. The recently discovered Midnolin employs a distinct, ubiquitin-independent "capture-degradation" mechanism that engages the proteasome directly, offering a complementary mechanistic strategy. However, the design principles, domain requirements, and substrate selectivity of Midnolin-based targeting chimeras (MidTAC) remain poorly understood. In this study, we systematically optimized the MidTAC platform and defined its functional boundaries. We demonstrated that optimal degradation activity requires the targeting module, the anti-GFP nanobody VHHGFP4 (variable domain of heavy chain of heavy-chain-only antibody against GFP variant 4), to be fused to the N-terminus of full-length Midnolin, as C-terminal or internal insertions are ineffective. Domain dissection revealed that neither the ubiquitin-like (UBL) domain nor the alpha-helical C-terminal (αHelix-C) domain alone, nor their simple tandem, is sufficient for degradation; the intact spatial conformation of the Midnolin scaffold is essential. Notably, MidTAC efficiently degraded substrate proteins irrespective of their subcellular localization, demonstrating its broad-spectrum utility. Furthermore, fusing the VHL E3 ligase to the C-terminus of Midnolin significantly enhanced degradation efficiency, suggesting a synergistic effect between ubiquitin-independent capture and ubiquitin-dependent recruitment. Collectively, these findings provide the first systematic characterization of MidTAC configuration, domain requirements, and broad-spectrum degradability, establishing a refined framework for engineering of next-generation BioPROTACs with an expanded substrate range.
    Keywords:  BioPROTACs; MidTAC; Midnolin; targeted protein degradation; ubiquitin-independent degradation
    DOI:  https://doi.org/10.1038/s41401-026-01959-7
  14. Chem Biol Interact. 2026 Oct 19. pii: S0009-2797(26)00500-4. [Epub ahead of print]440 112392
    The unfolded protein response as a proteotoxic stress-resolution circuit: branch-selective signaling and failed resolution in environmental immunotoxicity.
    Ardie Barry Sailis.
      Environmental immunotoxicity is commonly framed through oxidative stress, cytotoxicity, inflammation, receptor-mediated signaling and cell- or tissue-specific mechanisms. This review proposes that proteotoxic stress resolution represents an additional layer linking environmental exposure to immune dysfunction. Specifically, the unfolded protein response (UPR) is considered as a branch-selective proteotoxic stress-resolution circuit that can shape immune outcomes when endoplasmic reticulum (ER) homeostasis is perturbed. The framework is offered as a hypothesis-generating conceptual structure rather than an established mechanistic paradigm, and the causal step linking failed resolution to immune dysfunction remains largely extrapolated from non-toxicological ER-stress models. Evidence from ER proteostasis biology, immune-cell function and toxicology indicates that environmental toxicants can disrupt protein folding, ER calcium balance, redox homeostasis, lipid composition, degradation pathways and secretory load, thereby engaging distinct combinations of IRE1α, PERK and ATF6 signaling. These branches generate immune-relevant outputs: IRE1α links ER stress to RNA processing and inflammatory signaling, PERK controls translational suppression and fate selection, and ATF6 supports restoration of folding capacity and secretory competence. Across macrophages, dendritic cells, T cells, plasma cells and barrier epithelial cells, immune outcomes depend on branch bias, signaling duration, cell-type context and resolution through ER-associated degradation, autophagy, ER-phagy, translational recovery and restoration of calcium and redox balance. This framework predicts that repeated low-dose exposures, mixed toxicant inputs and incomplete post-exposure recovery can shift immune or barrier cells into inflammatory, suppressive or barrier-disruptive states without overt cytotoxicity. It also supports time-resolved, branch-specific and cell-specific profiling for immunotoxic risk assessment.
    Keywords:  ER stress; Environmental immunotoxicity; Proteostasis; Stress resolution; Toxicant exposure; Unfolded protein response
    DOI:  https://doi.org/10.1016/j.cbi.2026.112392
  15. Cell. 2026 Oct 21. pii: S0092-8674(26)01197-9. [Epub ahead of print]
    Proteomic atlas of T cell exhaustion defines proteostatic collapse.
    Sydnye L Shuttleworth, Michael A Bauer, Dennis W Province, Jessica L Kelliher, Nicole E Scharping, Alexander Monell, Lora J Rogers, Thomas A Williams, Grant T Dawson, Katherine F Wallis, Duah Alkam, Jacob L Edmondson, Daniel Fil, Aaron J Storey, Anna L Bolding, Rick D Edmondson, Stephanie D Byrum, Karen E Beenken, Samuel G Mackintosh, Ananda W Goldrath, Alan J Tackett, Brian Koss.
      T cell exhaustion limits the success of cancer immunotherapies, yet the proteomic changes underlying this dysfunctional state remain poorly understood. We integrated transcriptomics, quantitative proteomics, turnover proteomics, and ubiquitin proteomics to construct a multi-omic atlas of T cell exhaustion. These studies identified pathways regulated through transcriptional and post-translational mechanisms, including degradative and nondegradative ubiquitin modifications, and uncovered widespread changes in proteostasis, metabolism, and DNA repair. Major shifts were revealed in the ubiquitin-proteasome system, as differential expression of E3 ubiquitin ligases correlates with immunotherapy outcomes. These findings position the collapse of proteostasis as a central, underappreciated feature of T cell exhaustion and reveal opportunities to restore T cell function. We demonstrate that overexpression of the E3 ligase RNF166 enhances T cell persistence in vitro and in vivo. This work defines proteome-turnover dynamics as a critical regulatory layer in progressive T cell dysfunction, with broad implications for advancing cancer immunotherapy through manipulation of E3 ligases.
    Keywords:  CAR-T; E3 ubiquitin ligase; T cell; cancer immunotherapy; cell therapy; exhaustion; half-life; protein-turnover dynamics; proteostasis; ubiquitin
    DOI:  https://doi.org/10.1016/j.cell.2026.09.051
  16. J Cell Biol. 2026 Nov 02. pii: e202511137. [Epub ahead of print]225(11):
    ClC-7 links PIKfyve inhibition to Rab-dependent LRRK2 activity at lysosomes.
    Devin Clegg, Amanda Bentley-DeSousa, Agnes Roczniak-Ferguson, Shawn M Ferguson.
      Increased activity of leucine-rich repeat kinase 2 (LRRK2) confers Parkinson's disease risk. LRRK2 dynamically localizes to lysosomal membranes in response to various stresses, yet the mechanisms by which distinct lysosomal perturbations are communicated to LRRK2 remain unclear. Here, we show that inhibition of the lysosomal lipid kinase PIKfyve promotes LRRK2 recruitment and signaling through a pathway that requires the lysosomal chloride/proton antiporter ClC-7. ClC-7 in turn controls the accumulation of multiple Rab GTPases on lysosomes. LRRK2 signaling under these conditions requires its established Rab-binding surfaces, with Rab12 contributing significantly to this response. This pathway operates independently of CASM. In contrast, lysosomal stresses that induce CASM require both Rab-binding sites on LRRK2 and GABARAP for robust LRRK2 signaling. These findings identify ClC-7-dependent lysosomal remodeling and Rab accumulation as key features linking PIKfyve inhibition to LRRK2 signaling and reveal that distinct lysosomal stresses engage different combinations of Rab and GABARAP inputs to activate LRRK2.
    DOI:  https://doi.org/10.1083/jcb.202511137
  17. ACS Chem Biol. 2026 Oct 21.
    Improving PROTAC-Mediated Degradation in Mouse Models: BRD9 as a Case Study.
    Brayden P Strohmier, Jude T Quarshie, Rinky Raghuvanshi, Sukhmandeep Kaur, Gabriella G Conjelko, Emily C Dykhuizen.
      Proteolysis-targeting chimeras (PROTACs) have emerged as powerful chemical tools and therapeutics, yet their translation from preclinical models to humans remains inconsistent. Here, we systematically evaluate the activity of BRD9-targeting PROTACs in human and mouse systems to elucidate a key limitation in preclinical studies. Widely used CRBN- and VHL-recruiting degraders, including dBRD9 and VZ185, exhibit markedly reduced potency in mouse cells despite high sequence conservation of BRD9. Mechanistic interrogation reveals that species-specific differences in E3 ligases, particularly the Crbn I391 residue and structural variations in VHL, likely impair productive ternary complex formation. Expression of human CRBN or VHL, or introduction of the CrbnI391V mutation, increases degradation potency in mouse cells. Importantly, in vivo studies demonstrate enhanced BRD9 degradation in CrbnI391V mice using clinically relevant degraders. These findings highlight a critical barrier in PROTAC evaluation and establish humanized E3 ligase models as tools for more accurate assessment of on-target efficacy and toxicity.
    DOI:  https://doi.org/10.1021/acschembio.6c00628
  18. mBio. 2026 Oct 22. e0215226
    Atypical E3 ligase HOIL1 promotes MDA5 signaling and ester-linked ubiquitination of LGP2.
    Deion Cheng, Junji Zhu, W A Gayan Chathuranga, Surajit Chakraborty, GuanQun Liu, Rachel E Lacoursiere, Jonathan N Pruneda, Michaela U Gack, Donna A MacDuff.
      The RIG-I-like receptors, RIG-I and MDA5, are innate sensors of RNA virus infections that are critical for mounting a robust antiviral immune response. Heme-oxidized IRP2 ligase 1 (HOIL1), a component of the linear ubiquitin chain assembly complex (LUBAC), is essential for interferon induction in response to viruses sensed by MDA5, but not viruses sensed by RIG-I; however, the underlying mechanism remains unclear. LUBAC contains two atypical E3 ubiquitin ligases, HOIL1 and HOIP. While HOIP generates "linear" polyubiquitin chains, HOIL1 catalyzes ester-linked ubiquitination of serine and threonine residues and glucosaccharides. Here, we show that HOIL1 E3 ligase activity is critical for MDA5-dependent interferon induction, whereas HOIP E3 ligase activity plays a minor role. Mechanistically, HOIL1 E3 ligase activity was required for MDA5 translocation to mitochondrion-associated membranes and the formation of MAVS aggregates. We further identified LGP2, a positive regulator of MDA5 oligomerization, as a HOIL1-interacting protein and substrate for ester-linked ubiquitination. In mice, loss of HOIL1 or its E3 ligase activity markedly impaired early interferon responses following infection with viruses sensed by MDA5. While HOIL1 deficiency resulted in increased viral burden and reduced survival, loss of HOIL1 ligase activity alone did not, indicating that HOIL1 exerts additional functions during antiviral immunity. Collectively, these findings establish ester-linked ubiquitination by HOIL1 as a critical mechanism regulating MDA5 signaling.IMPORTANCEThe rapid and robust production of interferon is critical for controlling viral infections. Cytoplasmic RNA sensors, RIG-I and MDA5, detect infection with distinct groups of viruses, leading to the transcriptional induction of interferon. However, inappropriate production of interferon triggered by aberrant MDA5 activation by cellular RNAs causes severe inflammatory disorders. Here, we report that the ubiquitin ligase activity of heme-oxidized IRP2 ligase 1 (HOIL1) is critical for the production of interferon in response to viruses that are sensed by MDA5 in cells and mice. We identify the third RIG-I-like receptor, LGP2, as a substrate for ester-linked ubiquitination by HOIL1, and show that, like LGP2, HOIL1 ubiquitin ligase activity is required for the efficient oligomerization of MDA5 and the initiation of downstream signaling leading to the induction of interferon. These findings reveal a new regulator of MDA5-driven interferon production and identify a potential therapeutic target for MDA5-mediated inflammatory diseases.
    Keywords:  HOIL1; LGP2; LUBAC; MDA5; RIG-I-like receptors; interferons; ubiquitination
    DOI:  https://doi.org/10.1128/mbio.02152-26
  19. Cell Chem Biol. 2026 Oct 19. pii: S2451-9456(26)00367-3. [Epub ahead of print]
    Selective USP32 inhibition reveals endosomal ubiquitin signaling and enables cell-permeable activity-based probes.
    Stephan Scherpe, Febe C Vermue, Vito Pol, Raymond Kooij, Adán Pinto-Fernández, Rayman T N Tjokrodirijo, Darragh P O'Brien, Iolanda Vendrell, Dharjath S Hameed, Ilana Berlin, Peter A van Veelen, Benedikt M Kessler, Paul P Geurink, Aysegul Sapmaz.
      Deubiquitinating enzymes (DUBs) regulate ubiquitin signaling and are attractive therapeutic targets, but selective chemical tools remain available for only a limited number of family members. Here, we report Huib32, the first potent and selective covalent inhibitor of ubiquitin-specific protease 32 (USP32). Huib32 rapidly and selectively engages USP32 in vitro and in cells, recapitulating USP32 loss of function by enhancing substrate ubiquitination, disrupting endosomal organization, and defining an expanded network of USP32-regulated membrane trafficking proteins. Building on Huib32, we develop the first cell-permeable activity-based probes for USP32, enabling direct visualization of active USP32 in cells and selective proteomic enrichment of the enzyme. Together, these first-in-class chemical tools establish selective chemical targeting of USP32 as an approach to interrogate endosomal ubiquitin signaling and provide a foundation for therapeutic exploration in cancers and other diseases associated with endocytic trafficking.
    Keywords:  ABPP; DUB inhibitors; USP32; activity-based probes; endocytosis; ubiquitomics
    DOI:  https://doi.org/10.1016/j.chembiol.2026.09.018
  20. J Transl Med. 2026 Aug 13. pii: 1331. [Epub ahead of print]24(1):
    BRAP maintains SEC24D stability to regulate ER stress and promote cervical adenocarcinoma progression.
    Hui Wang, Yingying Li, Jiaoyun Zheng, Jie Wang, Junyi Duan, Yuhuan Wang, Horst Christian Weber, Quanli Yang, Xiangping Qu, Mubiao Liu.
       BACKGROUND: Cervical adenocarcinoma (ADC) exhibits a poorer prognosis than cervical squamous cell carcinoma and lacks effective targeted therapies. Bombesin receptor- activated protein (BRAP, encoded by C6orf89) has been implicated in cell proliferation and stress responses in multiple biological contexts; however, its role in ADC progression and endoplasmic reticulum (ER) homeostasis remains unknown.
    METHODS: BRAP expression was evaluated in human cervical adenocarcinoma (ADC) tissues by immunohistochemistry and western blotting, and its clinicopathological significance was analyzed. BRAP function was investigated by siRNA-mediated knockdown in HeLa and SiHa cells using proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition (EMT) assays, and further validated in xenograft models. Ultrastructural alterations were examined by transmission electron microscopy. BRAP-interacting proteins were identified by yeast two-hybrid screening and validated by co-immunoprecipitation. ER stress, ER exit site (ERES) homeostasis, and autophagic flux were evaluated, and rescue experiments were performed by re-expression of BRAP or SEC24D.
    RESULTS: BRAP was markedly upregulated in cervical adenocarcinoma tissues and was associated with poor tumor differentiation. BRAP depletion selectively inhibited proliferation, migration, invasion, and EMT while promoting apoptosis in ADC-derived HeLa cells, but not in squamous cell carcinoma-derived SiHa cells. Mechanistically, BRAP deficiency disrupted ER homeostasis and selectively activated the PERK-ATF4-DDIT3/CHOP branch of the unfolded protein response (UPR), whereas pharmacological inhibition with GSK2606414 largely reversed these phenotypic alterations. We identified the COPII cargo adaptor SEC24D as a novel BRAP-interacting protein. BRAP maintained SEC24D protein stability by preventing excessive autophagy-lysosome-mediated degradation, thereby preserving ERES number and function, as reflected by SEC16A-positive ERES and peripheral LMAN1-positive structures, and maintaining ER-Golgi trafficking homeostasis. Restoration of SEC24D rescued ERES defects, attenuated PERK-dependent UPR activation, and reversed the impaired proliferation, migration, invasion, apoptosis, and EMT induced by BRAP depletion.
    CONCLUSION: BRAP promotes cervical adenocarcinoma progression by maintaining SEC24D stability and preserving ERES organization and function, thereby sustaining COPII-dependent ER export and ER homeostasis. Disruption of the BRAP-SEC24D axis impairs ERES integrity, activates PERK-dependent ER stress, and suppresses malignant phenotypes. These findings identify BRAP as a previously unrecognized regulator of ER homeostasis and establish the BRAP-SEC24D signaling axis as a potential therapeutic target for cervical adenocarcinoma.
    Keywords:  BRAP; Cervical adenocarcinoma; EMT; ER stress; URP
    DOI:  https://doi.org/10.1186/s12967-026-08780-0
  21. Nature. 2026 Oct 21.
    GRP75-dependent SIMPA mediates inter-organellar quality control.
    Fan Yu, Lingyu Jiang, Hanyu Liu, Song Yang, Yuan Yuan, Hongzhen Jin, Jinming Liu, Xi Liu, Yu Dong, Dongfeng Ren, Jie Kang, Yan Huang, Qi Meng, Feng Bai, Yanjun Li, Shuoguo Li, Huadong Liu, Wei Zhao, Jia Xiao, Quan Chen.
      Mitochondria are bound by a double membrane and are semiautonomous organelles, rendering them highly vulnerable to global and internal proteostatic stress1. Multiple surveillance mechanisms at proteostatic and inter-organellar levels have evolved to maintain mitochondrial integrity and cellular health2-7. However, the precise mechanisms by which proteostatic damage relays stress signals across organelles and how the quality surveillance machinery coordinates these functions remain unknown. Here we report that under proteostatic stress, damaged mitochondrial proteins are sequestered to form stress-induced mitochondrial protein aggregates (SIMPAs) that activate specific quality control mechanisms in a spatially confined manner without perturbing the mitochondrial network. Quantitative proteomic and correlative light-electron microscopy analysis revealed that SIMPA mediates inter-organellar communication via mitochondria-endoplasmic reticulum contact sites or mitochondrial-associated membranes. Mechanistically, GRP75 coordinates SIMPA biogenesis and focally activates endoplasmic reticulum unfolded protein response pathways via mitochondria-endoplasmic reticulum contact sites or mitochondrial-associated membranes for the targeted clearance of SIMPAs. Functionally, in both cellular and liver disease models, we found that a GRP75-dependent SIMPA signalling cascade attenuates mitochondrial stress and preserves mitochondrial integrity under proteotoxic stress. Overall, we show that SIMPAs, functioning as protein condensates, serve as a central cross-compartment communication hub for mitochondrial quality control, supporting cellular and organismal fitness.
    DOI:  https://doi.org/10.1038/s41586-026-10733-y
  22. Biochemistry. 2026 Sep 15. 65(18): 2916-2927
    The Long Splice Variant of Ribosomal Protein S24 Protects Cells from Stress and Is Induced by AMPK-ULK1-Regulated Autophagy Independent of mTORC1.
    Runqi Qian, Jenna Goodbrand, Shannon N Adams, Erin Trella, James Uniacke.
      All living organisms have developed complex mechanisms to detect and react to environmental changes to maintain internal balance and support survival. One strategy that cells employ to respond to stress is to refocus the translation machinery to express select stress response proteins, this includes the emerging field of specialized ribosomes. We have previously shown that a long splice variant of ribosomal protein S24 (RPS24L) is induced by several fold in hypoxic monolayers and spheroids in several human cell lines in an autophagy-dependent manner. Here, we show that an allosteric activator of AMPK is sufficient to induce RPS24L and autophagy in normoxia in an ULK1-dependent, but mTORC1-independent manner. Overexpression of RPS24L protected cells from serum starvation and hypoxia, while RPS24 short isoform overexpression during stress impaired autophagy and the ability for cells to survive relative to controls. We show that SRSF1 interacts with RPS24 mRNA and its autophagy-dependent decrease shifts splicing toward the RPS24L variant. This study provides new insights into the signaling and mechanisms that regulate a ribosomal protein splice isoform that protects cells from stress and that has been previously linked to cancer progression.
    DOI:  https://doi.org/10.1021/acs.biochem.6c00572
  23. Ageing Res Rev. 2026 Oct 22. pii: S1568-1637(26)00418-6. [Epub ahead of print] 103426
    Receptor-Specific ER-Phagy in Neurodegenerative Diseases: Molecular Mechanisms and Emerging Therapeutic Opportunities.
    Suramya Malhotra, Rajat Sandhir.
      Neurodegenerative diseases (NDs) constitute a major global health burden driven by rising life expectancy and the lack of disease-modifying therapies. Central to these progressive pathologies is the accumulation and aggregation of conformationally altered proteins, categorizing them as 'proteinopathies'. These aberrant aggregates disrupt cellular homeostasis and trigger chronic stress responses that drive progressive neuronal dysfunction and loss. The endoplasmic reticulum (ER) is a dynamic organelle defined by remarkable structural diversity and functional plasticity, that preserves cellular homeostasis by orchestrating protein folding and quality control, lipid biosynthesis, calcium sequestration and metabolic detoxification. However, sustained ER stress and functional dysregulation are increasingly implicated in neurodegenerative cascades. In this context, ER-selective autophagy (ER-phagy) has emerged as an indispensable quality-control pathway. Mediated by dedicated ER-phagy receptors that target distinct subdomains for lysosomal clearance, this pathway preserves organellar integrity and mitigates proteotoxic burden in post-mitotic neurons. Nonetheless, the full mechanistic landscape of ER-phagy remains poorly defined, with receptor-specific functions, regulatory signalling networks and CNS expression profiles only beginning to be resolved. This review synthesizes current insights into ER-phagy in neurodegeneration, dissects receptor-specific mechanisms, and highlights emerging pharmacological interventions. Ultimately, the therapeutic potential of modulating receptor-specific ER-phagy as an untapped strategy to resolve ER stress, re-establish neuronal proteostasis and to combat neurodegenerative conditions is highlighted.
    Keywords:  Autophagy; ER-phagy; Endoplasmic Reticulum; Misfolded protein; Neurodegenerative diseases; Proteinopathy
    DOI:  https://doi.org/10.1016/j.arr.2026.103426
  24. Sci Adv. 2026 Oct 23. 12(43): eaee3876
    PhagoID: Quantitative in situ proximity labeling defines the proteomes of bead- and microbe-containing phagosome lumina across species, maturation, and immune activation.
    Benjamin L Allsup, Supriya Gharpure, Cal Gunnarsson, Mateo L Stagg, Bryan D Bryson.
      The phagosome is an immune organelle that integrates signals from diverse cargos to drive pathogen killing, tissue homeostasis, and antigen presentation. How this compartment coordinates such diverse functions remains incompletely understood. A comprehensive view of phagosomal composition across cell states and perturbations could accelerate insight into its regulation. Here, we establish PhagoID, a modular proximity labeling approach that enables in situ proteomic profiling of the phagosome lumen in living cells. Applying PhagoID to murine and human macrophages, we define conserved and species-specific phagosomal proteomes that include both canonical lysosomal components and unexpected contributors from nuclear, mitochondrial, and endoplasmic reticulum (ER) compartments. Integrating these proteomes with 25 genome-scale CRISPR screens of phagosomal phenotypes, we identify a network of lumenal proteins that regulate cargo uptake, acidification, antigen presentation, and microbial control highlighting previously unrecognized phagosomal effectors. We next adapt PhagoID to profile the microbe-containing phagosome and compare the sterile bead-containing phagosome to the Escherichia coli-containing phagosome, demonstrating a modest E. coli signature of phagosome remodeling. Comparative analyses further reveal that loss of LAMP1 enhances recruitment of ER-derived proteins to the phagosome, whereas loss of TFEB minimally perturbs the lumenal proteome despite its role in lysosomal biogenesis. Last, cytokine stimulation remodels the phagosome lumen to enrich for proteins involved in antigen presentation and antimicrobial activity in response to type I and II interferons. These data demonstrate that PhagoID delivers a high-confidence, quantitative, and integrative map of the phagosome lumen, revealing previously unidentified axes of organellar communication and regulatory control in innate immunity.
    DOI:  https://doi.org/10.1126/sciadv.aee3876
  25. Autophagy. 2026 Oct 23.
    SSH1 knockdown increases autophagosome formation through ATG9A recruitment and promotes tau protein degradation.
    Morgan C Stephens, Richard I Han, Alma M Perez, Hilary Chester, Maria de Haro, Arsh Ali, Amy Hammett, Ruhee Dere, Ismael Al-Ramahi, Juan Botas.
      Pathological accumulation of MAPT/tau protein is a defining feature of Alzheimer disease (AD) and related tauopathies, highlighting the need to identify druggable regulators of MAPT/tau clearance. Using Drosophila behavioral assays focused on cytoskeletal remodeling pathways dysregulated in AD, we identified genes whose genetic modulation mitigates MAPT/tau-induced behavioral deficits. These modifiers were validated by histopathology and mechanistically examined in human tauopathy cell models to determine their impact on autophagy-dependent MAPT/tau degradation. Autophagic flux, ATG9A trafficking, and autophagosome biogenesis were further analyzed. Across models, reduction of the phosphatase SSH1 consistently lowered steady-state MAPT/tau levels by enhancing autophagic flux through a mechanism distinct from its canonical regulation of CFL1. Mechanistically, SSH1 functions as a negative regulator of early autophagosome formation: SSH1 depletion promotes ATG9A mobilization to the endoplasmic reticulum-phagophore assembly site (ER-PAS), thereby accelerating autophagic vesicle biogenesis. Importantly, the MAPT/tau-lowering effect of Dmssh attenuation was abolished in flies haploinsufficient for DmAtg9, demonstrating that SSH1-mediated MAPT/tau clearance requires ATG9 function. Consistent with a direct regulatory interaction, in vitro phosphatase assays revealed that recombinant SSH1 decreases ATG9A phosphorylation in the presence of actin, identifying an SSH1-ATG9A regulatory axis controlling autophagosome initiation. These findings position SSH1 as a nodal inhibitor of autophagy initiation whose inhibition enhances MAPT/tau proteolysis. Notably, SSH1 haploinsufficiency also reduces SNCA/α-synuclein accumulation in vivo, indicating broader relevance to neurodegenerative proteopathies. By integrating in vivo functional screening with mechanistic studies in human cells, this work identifies SSH1 as a druggable phosphatase that constrains autophagy at the level of ATG9A-dependent vesicle formation.
    Keywords:  Autophagosome biogenesis; MAPT/tau aggregation; autophagy; flux; lysosomal degradation; phosphatase; proteopathy
    DOI:  https://doi.org/10.1080/15548627.2026.2752745
  26. Med Res Rev. 2026 Oct 18.
    Aptamer-Based Targeted Protein Degradation: Mechanistic Principles, Delivery Strategies, and Translational Opportunities.
    Ambrin Malik, Suyeon Son, Jaesung Lee, Ki Soo Park.
      Targeted elimination of pathogenic proteins remains a fundamental challenge in therapeutic intervention, particularly for proteins considered "undruggable" by conventional inhibition-based approaches. Aptamer-based targeted protein degradation (TPD) has emerged as a versatile strategy that leverages the high specificity, structural programmability, and chemical tunability of nucleic acid aptamers to redirect disease-relevant proteins toward endogenous degradation pathways. Intracellular platforms, exemplified by aptamer-conjugated proteolysis-targeting chimeras (PROTACs), induce ubiquitination and proteasomal degradation of cytosolic and nuclear targets. In parallel, extracellular and membrane-targeting modalities, including aptamer-conjugated lysosome-targeting chimeras (LYTACs) and related lysosomal degradation systems, enable clearance of secreted and membrane-bound proteins that are inaccessible to proteasome-based strategies. Collectively, these approaches broaden the potentially degradable proteome and offer opportunities to improve target selectivity and therapeutic safety. However, most aptamer-based TPD systems remain at the proof-of-concept or early preclinical stage, with limited standardization of degradation potency, kinetics, selectivity, and in vivo efficacy. Additional challenges include the discovery of functionally active aptamers, preservation of affinity and activity after chemical modification or conjugation, efficient delivery, chemical stability, controlled biodistribution, and mitigation of innate immune activation. This review provides a mechanistic and comparative framework for intracellular and extracellular aptamer-based TPD strategies, with emphasis on quantitative performance, delivery considerations, technical bottlenecks, and their translational potential for precision protein-targeted therapeutics.
    Keywords:  LYTAC; PROTAC; aptamer; lysosomal degradation; targeted protein degradation
    DOI:  https://doi.org/10.1002/med.70110
  27. Brief Bioinform. 2026 Sep 01. pii: bbag575. [Epub ahead of print]27(5):
    Ribo-seq rRNA reads reveal co-predicted signatures of ribosome heterogeneity and collisions.
    Edwin S Kyei-Baffour, William J Faller, Ferhat Alkan.
      Ribosome heterogeneity is increasingly recognized as a key factor in various biological contexts, including development, cancer, and immune responses. To enable systematic exploration of this diversity, we previously developed a bioinformatics method that utilized rRNA reads from Ribo-seq data, detecting changes in ribosomal protein composition (dripARF) and ribosome collisions (dricARF) between conditions simply and efficiently. The method works by projecting differences in rRNA read abundance onto the 3D-structure of the ribosome, following which we perform enrichment tests on predefined heterogeneity-specific rRNA position sets. In this study, we apply this tool to publicly available Ribo-seq datasets to understand the impact of experimental protocol variations and to identify shared biological signals across studies. Our analyses show that the rRNA regions assigned to our prediction sets are consistently enriched in rRNA reads, supporting the core assumptions of our approach. We further examine how various protocol factors influence rRNA read distribution and implement a single-sample rRNA position set enrichment analysis-based weight to limit false positives. Finally, we highlight consistent ribosomal changes across these studies, including prominent co-predictors such as ribosome collisions, eS25, and uS19.
    Keywords:  Ribo-seq; rRNA reads; ribosome collisions; ribosome heterogeneity
    DOI:  https://doi.org/10.1093/bib/bbag575
  28. J Phys Chem B. 2026 Oct 22. 130(42): 11132-11165
    Chaperonopathies as Disorders of Disorder: The Role of Intrinsically Disordered Regions in Proteostasis Dysfunction.
    Adna Berilo, Naida Odobašić, Merjem Husić, Altijana Hromić-Jahjefendić, Muhamed Adilović, Vladimir N Uversky.
      Molecular chaperones are central regulators of the proteostasis network, ensuring proteome integrity through protein folding, the prevention of aggregation, and targeted degradation. These mechanisms are essential for limiting proteotoxic stress and preventing the accumulation of pathogenic proteins. Consequently, chaperone dysfunction is linked to various diseases including genetic chaperonopathies caused by pathogenic mutations. The most commonly affected chaperones include small heat shock proteins (sHSPs; HSPB1, HSPB3, HSPB5, HSPB8), Hsp60 (HSPD1), Hsp70 (HSPA9/mortalin), and the CCT/TRiC complex. sHSPs are ATP-independent chaperones critical under stress conditions and are characterized by intrinsically disordered regions (IDRs), particularly in flexible terminal regions. Although structurally important, IDRs are frequently targets of disease-associated mutations. In this study, intrinsic disorder in chaperones linked to genetic chaperonopathies was analyzed using bioinformatics tools, followed by a focused evaluation of highly disordered proteins and their disease associations. The results highlight intrinsic disorder as a conserved and functionally essential feature. HSPB1 and HSPB8 show high disorder levels, consistent with roles in neural proteostasis and neuropathies. HSPB3 and HSPB5 exhibit moderate disorder but harbor mutations linked to muscle and cardiac diseases. In contrast, HSPB6 dysfunction is mainly driven by post-translational modifications, rather than mutations. Overall, genetic chaperonopathies can be viewed as intrinsic-disorder-related diseases.
    DOI:  https://doi.org/10.1021/acs.jpcb.6c05122
  29. Acc Chem Res. 2026 Oct 20. 59(20): 3336-3346
    Chemically Induced Proximity for Targeted Protein O-GlcNAcylation.
    Bowen Ma, Tongyang Xu, Zhihao Guo, Billy Wai-Lung Ng.
      O-GlcNAcylation is a ubiquitous post-translational modification across the mammalian proteome, yet determining how individual O-GlcNAcylation events control specific protein functions remains a central challenge. The O-GlcNAc cycle is governed by two enzymes: O-GlcNAc transferase (OGT), which installs O-GlcNAc, and O-GlcNAcase (OGA), which removes it. Because these enzymes act on thousands of proteins, conventional methods, such as pharmacological inhibition of OGT or OGA, produce broad cellular effects that are difficult to assign to individual substrates. This gap has motivated the development of targeted O-GlcNAcylation strategies, including genetically encoded and chemical biology tools, which have shown that O-GlcNAc can be selectively installed on defined proteins to interrogate protein-specific O-GlcNAc functions. This Account describes the development of O-GlcNAc TArgeting Chimeras, or OGTACs, as chemical tools for targeted O-GlcNAc installation. OGTACs are bifunctional molecules that can recruit OGT to a specific protein of interest. Specifically, an OGTAC consists of an OGT-engaging element, a linker, and a target-recognition motif, which together bring OGT into proximity with a selected substrate. Our studies show that chemically induced proximity can redirect OGT toward selected proteins, thereby creating targeted O-GlcNAc writing that can partially bypass TPR-domain-mediated substrate recognition under engineered recruitment conditions. A central lesson is that productive O-GlcNAc writing requires not only recruitment, but also proper ternary-complex formation and noninhibitory OGT engagement. Moreover, the target-recognition motif determines the targetable protein space and achievable selectivity of the platform. By linking local O-GlcNAc installation to changes in protein turnover, signaling, and transcriptional output, OGTACs provide a conceptual framework for using induced proximity to modulate protein functions.
    DOI:  https://doi.org/10.1021/acs.accounts.6c00453
  30. Nature. 2026 Oct 21.
    Cold activates a BH2 metabolic network promoting longevity and proteostasis.
    Hyun Ju Lee, Cansu Doğan, Seda Koyuncu, Markus Wehrmann, Murat Artan, Dunja Petrovic, Rute Loureiro, Amit Kumar Sahu, Joana Schnubel, Pavel Grobushkin, Dimitrios Prymidis, Theodoros Georgomanolis, Agnieszka Sokol, Ming Yang, Thorsten Hoppe, Christian Frezza, David Vilchez.
      Moderately cold temperatures extend lifespan and promote health across species1-3, yet the molecular mechanisms underlying these benefits remain unclear. Here we define a metabolite-driven, multi-tissue signalling system that links cold temperature to enhanced longevity and proteostasis in Caenorhabditis elegans. Cold temperature upregulates the biopterin-synthesis enzyme CAT-4 (GCH1 in humans), increasing production of dihydrobiopterin (BH2), a transportable reservoir for the bioactive cofactor tetrahydrobiopterin (BH4). BH2 is produced in muscle and transported to distal tissues, including the intestine and neurons, where it is converted into BH4 by the salvage enzyme DHFR-1. BH4 functions as an essential cofactor for phenylalanine hydroxylase PAH-1, promoting tyrosine synthesis and extending lifespan. This BH2-BH4 axis also prevents disease-related protein aggregation and subsequent neuronal dysfunction during ageing. Importantly, increasing BH2 synthesis specifically in muscle is sufficient to promote longevity and suppress pathological protein aggregation in distal tissues, even at normal or elevated temperatures. In human cells, BH2 or tyrosine supplementation reduces aggregation of polyQ-expanded proteins associated with Huntington's disease, as well as mutant variants of TDP-43 and FUS that cause amyotrophic lateral sclerosis. Together, these findings identify BH2 as a cold-induced metabolite of which the synthesis, intertissue transport and conversion into bioactive BH4 preserve organism-wide proteostasis and extend lifespan.
    DOI:  https://doi.org/10.1038/s41586-026-11152-9
  31. Proc Natl Acad Sci U S A. 2026 Oct 27. 123(43): e2623700123
    Comparative analysis of photocatalytic, enzymatic, and chemical approaches to identify canonical and noncanonical surfaceomes.
    William W Ho, Yifei Chen, Tomasz Slezak, Oleksandr Zginnyk, Trenton M Peters-Clarke, Kaitlin Schaefer, Anthony A Kossiakoff, Kevin K Leung, James A Wells.
      The cell surface is a critical nexus in cellular communication and a rich landscape yielding the majority of current therapeutic targets, yet only a small fraction of cell surface proteins have been targeted therapeutically. The cell surface proteome (surfaceome) comprises only ~1% of the human proteome by mass, motivating enrichment strategies to detect surfaceome alterations in disease for drug target discovery. Developments in photocatalytic technology have revolutionized the study of protein neighborhoods around specific targets of interest, but photocatalysis has been underutilized for global surfaceome analysis. Here, we describe five distinct photocatalytic surfaceomics strategies, all without the need for cellular engineering, that apply the photocatalyst Eosin Y attached to different cell surface structures: direct glycan ligation, glycan attachment via two different lectins, membrane insertion, and free in extracellular space. We systematically compare these photocatalytic surfaceomics methods to each other as well as to three established chemical and enzymatic surfaceomics methods. We demonstrate that the different photocatalytic surfaceomics techniques achieve broadly similar canonical cell surface protein enrichment but show some important differences reflective of cell surface attachment mechanism. These mechanistically orthogonal surfaceomics techniques consistently identified numerous nonglycosylated proteins with high concordance, many of which represent an underappreciated class of noncanonical cell surface proteins lacking traditional cell surface protein features that may represent potential drug targets. This study substantially expands options for surfaceomics methods using photocatalytic proximity labeling.
    Keywords:  cell surface; membrane proteins; photocatalysis; proxmity labeling; surfaceomics
    DOI:  https://doi.org/10.1073/pnas.2623700123
  32. Nat Commun. 2026 09 21. pii: 10993. [Epub ahead of print]17(1):
    Structure of Blm10:13S proteasome intermediate reveals parallel assembly pathways for the proteasome core particle.
    Mandeep Kaur, Xiang Chen, Stella Y Lee, Tyler M Weaver, Bret D Freudenthal, Kylie J Walters, Jeroen Roelofs.
      The proteasome core particle (CP) can be capped by Blm10/PA200, which promotes ATP-independent degradation of disordered proteins and contributes to attenuating antigenic diversity and impacts immunotherapy upon upregulation. The assembly process that leads to Blm10-CP proteasomes remains unresolved and Blm10 is present not only at mature proteasomes but also bound to assembly intermediates. We identified and solved structures of five CP intermediate complexes by cryo-electron microscopy, two of which include Blm10. We find that CP intermediates interactions with Blm10 and Pba1/Pba2 chaperone complex are mutually exclusive and both leads to mature CP production. We further find no synergy between Pba1/Pba2 and Blm10 for CP assembly. These data suggest a parallel assembly pathway exists for Blm10 proteasomes that does not require sequential activity with Pba1/Pba2. Whereas CP affinity for Pba1/Pba2 is reduced during maturation to promote its release, no such affinity switch occurs for Blm10, further suggesting a parallel Blm10-assembly pathway for production of mature Blm10-bound CPs. Altogether, our findings reveal a functionally distinct CP assembly pathway for the production of mature Blm10-CP proteasomes.
    DOI:  https://doi.org/10.1038/s41467-026-77943-w
  33. J Med Chem. 2026 Oct 22. 69(20): 24619-24644
    Discovery of a Protein Kinase R-like Endoplasmic Reticulum Kinase (PERK) Inhibitor Suitable for Clinical Progression.
    Paul A Glossop, Samuel Brookes, Neil Flanagan, Melanie S Glossop, Krishna K Kolluri, Charlotte A L Lane, Clara Stead, Susanne Wright, Richard P Butt, Nadine Clemo, Emmanuel H Demont.
      Protein kinase R-like endoplasmic reticulum kinase (PERK) is a key sensor in the integrated stress response (ISR) and the unfolded protein response (UPR), playing a critical role in tumor cell survival under stress conditions. Based on literature data, we identified the novel PERK inhibitor 17, of moderate potency but promising kinase selectivity and in vivo pharmacokinetics. A lead optimisation campaign focussing on careful control of lipophilicity (log D) and lipophilic ligand efficiency (LLE) led to the identification of 49 (APL-11056), a potent and selective PERK inhibitor. High permeability contributes to its excellent in vivo pharmacokinetics and can be linked to the presence of a fluorine alpha to the core benzamide, which limits recognition by efflux transporters.
    Keywords:  PERK; clinical candidate; fluorine; kinase; lipophilic ligand efficiency; orthosteric inhibitor
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c02120
  34. Med Res Rev. 2026 Oct 21.
    Landscape of Endocytic Effectors for Extracellular Targeted Protein Degradation.
    Yuxin Liang, Shiqun Shao, Yuping Chen, Jingxing Si, Youqing Shen.
      Extracellular targeted protein degradation (eTPD) has emerged as a new strategy for regulating the abundance and activity of extracellular and membrane proteins, with prominent potential to address traditionally undruggable targets in oncology, autoimmune diseases, and neurodegenerative disorders. Most eTPD platforms employ heterobifunctional chimeras that link proteins of interest (POIs) to specific endocytic effectors (EEs), either lysosome-targeting receptors (LTRs) or membrane-bound E3 ubiquitin ligases, to direct POIs to lysosomes for degradation. Since EE engagement dictates cellular uptake, intracellular trafficking route, recycling kinetics, tissue specificity, and overall degradation efficacy, one compelling topic in the eTPD community is to identify effective EEs for developing new eTPD tools. To inform new EE discovery, here we review the current landscape of EEs utilized in eTPD. We categorize LTRs based on their ligand specificity and discuss representative receptors including the cation-independent mannose-6-phosphate receptor (CI-M6PR) and the asialoglycoprotein receptor (ASGPR), with emphasis on their internalization and trafficking characteristics. For each category, we highlight representative degrader designs and assess how degrader attributes such as ligand format, valency, molecular size, linker chemistry, and linker length influence trafficking properties and degradation efficacy. We further discuss cell-surface E3 ligase-based degraders and emerging EE-independent strategies-receptor-independent membrane-interacting modalities exemplified by cell-penetrating peptides-that exploit alternative endocytic pathways without relying on specific effector expression. Finally, we discuss key challenges and future opportunities for integrating effector biology with degrader engineering to advance eTPD toward therapeutic drug discovery.
    Keywords:  E3 ubiquitin ligase; LYTAC; endocytic effector; endocytosis; extracellular targeted protein degradation; lysosomal degradation; membrane protein
    DOI:  https://doi.org/10.1002/med.70112
  35. Biochemistry. 2026 Sep 15. 65(18): 2905-2915
    Programmable Enhancement of IRES-Mediated Translation via RNA-Guided eIF4G Recruitment.
    Binbin Ying, Feiyang Zheng, Yoshinori Kawabe, Masamichi Kamihira.
      Internal ribosome entry sites (IRESs) enable cap-independent translation but often exhibit low and variable efficiency, limiting their use in synthetic gene circuits. Here, we present a programmable strategy to enhance IRES-dependent translation by recruiting a truncated eIF4G scaffold via engineered RNA-binding protein fusions. A λN-eIF4G fusion selectively increased EMCV IRES-mediated translation without affecting cap-dependent expression, achieving up to 7.7-fold enhancement. Translation output was tunable over a broad dynamic range through effector dosage and linker design, revealing key design parameters for controlling activity. The system functioned across multiple mammalian cell lines and in tricistronic constructs, enabling coordinated regulation of polycistronic expression. Computational modeling was consistent with preferential interaction between λN and the EMCV IRES. These results establish a modular framework for the programmable control of translation, define design principles for RNA-guided translational control, and expand the synthetic biology toolkit for post-transcriptional gene regulation.
    DOI:  https://doi.org/10.1021/acs.biochem.6c00420
  36. Sci Adv. 2026 Oct 23. 12(43): eaeg5840
    Structural basis for start codon selection by eIF5-mimic proteins.
    Ximena Zottig, Chun-Ying Huang, Zahra Seraj, Nikolaus Grigorieff, Andrei A Korostelev.
      Start codon selection extensively regulates the cellular proteome and is implicated in cancer and other diseases. The eIF5-mimic proteins (5MPs: 5MP1/BZW2 and 5MP2/BZW2) restrict non-AUG start codon usage and thereby reprogram proteoform expression from mRNAs with alternative start sites, such as the oncogenic c-Myc. Here, using in extracto cryo-electron microscopy (cryo-EM) and biochemical assays, we report how 5MP represses translation dependent on the sequence context at start codons. Cryo-EM structures of 48S preinitiation complexes (PICs) reveal 5MP1 bound at the A site of the small ribosomal subunit. 5MPs act as initiation factors that stabilize an open PIC conformation, promoting mRNA scanning and inhibiting initiation at suboptimal start codons. We propose to designate 5MP as eIF1S (eukaryotic initiation factor 1 scanning). These findings reveal the structural basis for proteome modulation by 5MPs and may help correct dysregulated translation in disease.
    DOI:  https://doi.org/10.1126/sciadv.aeg5840
  37. Redox Rep. 2026 Dec 31. 31(1): 2732775
    Protein disulphide isomerase protects against ALS/FTD phenotypes associated with cyclin F in zebrafish and cellular models.
    Sina Shadfar, Sonam Parakh, Emma Perri, Cyril Jones Jagaraj, Sara Assar Kashani, Keelin Beyers, Audrey M G Ragagnin, Angela S Laird, Julie D Atkin.
       BACKGROUND: Mutations in CCNF, encoding cyclin F, cause a small proportion of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) cases. Mutant cyclin F mislocalises from the nucleus to the cytoplasm, impairs the ubiquitin proteasome system, disrupts endoplasmic reticulum (ER) to Golgi transport, and triggers ER stress and apoptosis. Protein disulphide isomerase (PDI), a redox-active ER chaperone of the thioredoxin superfamily, protects against ALS phenotypes induced by mutant SOD1, TDP-43, and FUS, but its activity against mutant cyclin F has not been examined.
    OBJECTIVES: To test whether PDI overexpression prevents the cellular and behavioural phenotypes induced by the ALS/FTD-associated cyclin FS621G mutation.
    METHODS: Neuro-2a cells were co-transfected with mCherry-tagged wild-type or mutant cyclin FS621G and V5-tagged PDI or empty vector. Subcellular localisation, XBP-1 and CHOP activation, proteasome reporter (GFPu) accumulation, nuclear morphology, and cleaved caspase-3 immunoreactivity were assessed by confocal microscopy. Transient transgenic zebrafish larvae generated by mRNA co-injection of cyclin F and PDI were assessed by photomotor response at 48 h post-fertilisation.
    RESULTS: Mutant cyclin FS621G induced cytoplasmic mislocalisation, ER stress (assessed by XBP-1 and CHOP activation), proteasome dysfunction (indicated by GFPu accumulation), and apoptosis (assessed by nuclear condensation and caspase-3 activation), all of which were significantly attenuated by PDI co-expression. Zebrafish larvae expressing cyclin FS621G swam significantly shorter distances than uninjected or wildtype controls, and co-expression of PDI restored motor function to near-wildtype levels.
    CONCLUSION: PDI protects against ALS/FTD-associated mutant cyclin F in both cellular and in vivo zebrafish models, identifying PDI as a redox-based therapeutic target for CCNF-linked ALS/FTD.
    Keywords:  CCNF; ER stress; FTD; MND; ageing; cyclin F; neurodegeneration; proteostasis; zebrafish
    DOI:  https://doi.org/10.1080/13510002.2026.2732775
  38. iScience. 2026 Nov 20. 29(11): 117707
    A common germline 3' UTR variant controls DDIT4 translation efficiency and stress responses in cancer cells.
    Meriem Hadjer Hamadou, Laura Alunno, Tecla Venturelli, Samuel Valentini, Davide Dalfovo, Francesca Lorenzini, Alessia Mattivi, Vincenza Vigorito, Glenda Paola Grupelli, Alessandro Matte', Pamela Gatto, Michael Pancher, Chiara Valentini, Veronica De Sanctis, Roberto Bertorelli, Virginie Marcel, Emilio Cusanelli, Stefano Freddi, Giovanni Bertalot, Sara Zaccara, Marina Mione, Luca L Fava, Alessandro Romanel, Alberto Inga.
      Systematic strategies for identifying and classifying variants that directly modulate ribosome engagement are lacking. Here, we develop and extensively validate a pipeline to identify translation-associated single-nucleotide polymorphisms (tranSNPs) by integrating analysis of total and polysome-associated mRNAs. Common variants showing allele-specific enrichment in polysomes, without corresponding changes in mRNA levels, were uncovered. We focused on rs1053639, a frequent germline SNP located in the 3' UTR of DNA damage-inducible transcript 4 (DDIT4), a key negative regulator of mTORC1. Using edited cell models, we showed that this variant controls DDIT4 protein output. Mechanistically, the two rs1053639 alleles differ in their interaction with the RNA-binding protein RBMX, leading to altered mRNA subcellular localization and translation. Functionally, allele-specific regulation of DDIT4 translation impacts stress-dependent mTORC1 repression and autophagy, resulting in divergent competitive fitness in co-culture or xenograft assays and response to therapeutic perturbations. Analysis of cancer patient datasets revealed an association between rs1053639 genotype and clinical outcome in colorectal cancer.
    Keywords:  DDIT4; ER-stress; RBMX; mTOR; p53; polysome-profiling; translation
    DOI:  https://doi.org/10.1016/j.isci.2026.117707
  39. Nat Commun. 2026 09 17. pii: 10907. [Epub ahead of print]17(1):
    A lipoprotein-biomimetic nanoplatform for oncogenic KRAS mutation-specific lysosome-targeting protein degradation.
    Hang Yang, Xinyi Zhou, Jiafeng Wang, Chenyue Yang, Yuzhao Jin, Xufeng Liao, Xiangrui Liu, Chuansheng Guo, Qian Xiao, Quan Zhou, Kefeng Ding.
      Lysosome-targeting protein degradation strategies have evolved to leverage lineage-specific receptors to improve selectivity, yet remain unable to distinguish malignant from normal cells within the same lineage. Since oncogenic mutations are the defining feature of malignant cells, we here develop KRAS-mutated (MT) tumor targeting chimeras (KRASTAC), a lipoprotein-biomimetic nanoplatform that hijacks the enhanced macropinocytosis in KRAS-MT cells for mutation-specific protein degradation. KRASTAC potently degrades diverse proteins including epidermal growth factor receptor and programmed cell death ligand 1 (PD-L1) in KRAS-MT cells at a low antibody concentration of 2.5 nM within 9 h, with minimal impact in KRAS wild-type (WT) cells. Furthermore, KRASTAC exhibits mutation-specific tumor accumulation and protein degradation in vivo. KRASTAC-induced PD-L1 degradation leads to robust antitumor efficacy and reprogramming of the immunosuppressive microenvironment in mice carrying Kras-MT tumors. Our work presents KRASTAC as a potent mutation-specific protein degradation strategy for KRAS-MT cancers and establishes macropinocytosis as a route for lysosome-targeting protein degradation.
    DOI:  https://doi.org/10.1038/s41467-026-77697-5
  40. J Med Chem. 2026 Oct 08. 69(19): 21937-21954
    Hsc70-Mediated Targeting Chimeras for Targeted Protein Degradation via Chaperone-Mediated Autophagy.
    Chao Chen, Ying Zheng, Xiuyu Tao, Liya Yang, Chaoyue Wang, Xiaoqian Liu, Ruixi Zhao, Haokang Ding, Peng Sun, Haotian Liu, Shiqi Liu, Chenyuan Jiang, Min Huang, Bing Zhou.
      Despite the remarkable success of proteolysis-targeting chimeras (PROTACs), challenges such as limited applicability to certain cytosolic proteins, potential resistance risks, and off-target effects remain. Novel degradation strategies harnessing the autophagy/lysosome pathway may broaden the scope of protein targets and address resistance, providing a promising complement to PROTACs. Herein, the bifunctional small-molecule Hsc70-Mediated Targeting Chimeras, termed Hsc70TACs, was designed by conjugating a small molecule targeting Hsc70 with the ligands of the protein of interest (POI). We demonstrate the scope of Hsc70TACs through the degradation of therapeutically relevant proteins such as BRD4, MDM2 and even cell-membrane protein PD-L1 across diverse cellular contexts. More importantly, compound B-2, a novel BRD4 Hsc70TAC, shows favorable pharmacokinetic properties and robust in vivo BRD4 degradation, thus further highlighting the potential value of Hsc70TAC. Overall, Hsc70TAC demonstrates a new avenue to target and degrade disease-associated proteins, providing a valuable addition to current protein degradation technologies.
    Keywords:  Bifunctional small molecule; Chaperone-mediated autophagy; Hsc70 targeting chimera; Lysosomal degradation; Targeted protein degradation
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c01010
  41. Cell Mol Life Sci. 2026 Jul 24. pii: 388. [Epub ahead of print]83(1):
    Stella safeguards proteostasis via regulating UBE2D3 translation in the maternal-to-zygotic transition.
    Guorui Zhang, Minjie Ren, Guangyi Sun, Yilong Zhao, Na Zhang, Qiang Wang, Longsen Han.
      Ubiquitin-proteasome-mediated protein degradation is essential for maternal-to-zygotic transition, yet the maternal factors that safeguard ubiquitin-proteasome function remain unclear. Here, using a Stella-mutant mouse model, we demonstrate that Stella is required for global protein ubiquitination during early embryogenesis. Stella deficiency in oocytes leads to reduced ubiquitinated protein levels, impaired zygotic genome activation, and early developmental arrest. Proteomic and functional analyses identify UBE2D3 as the key E2 enzyme whose insufficiency underlies the ubiquitination defect. Mechanistically, Stella preserves YBX3 stability, thereby enabling YBX3-dependent translation of Ube2d3 mRNA. Consequently, Stella depletion destabilizes YBX3, diminishes UBE2D3 synthesis, and disrupts protein ubiquitination. Notably, overexpression of Ybx3 or Ube2d3 partially restores ubiquitinated protein levels, zygotic genome activation, and embryo development. These findings identify a previously unrecognized Stella-YBX3-UBE2D3 axis that ensures efficient maternal protein ubiquitination and zygotic genome activation, revealing a cytoplasmic mechanism by which maternal Stella governs proteostasis during maternal-to-zygotic transition.
    Keywords:  Maternal factor; Proteolysis; Translational control; Ubiquitination
    DOI:  https://doi.org/10.1007/s00018-026-06349-0
  42. J Med Chem. 2026 Oct 22. 69(20): 24137-24149
    Single-Atom Modification Enables Reversal of Degradation Selectivity between NSD2 and GSPT1.
    Weizhong Shen, Yihan Liu, Lianchao Liu, Yingfan Liu, Yan Zhang, Yihan Chen, Lei Wang, Zhiyi Zhou, Angela Zhang, Hui Shen, Fengtao Zhou, Weixue Huang, Xiaomei Ren, Abhijit Parolia, Yong Xu, Yang Zhou, Zhen Wang, Arul M Chinnaiyan, Ke Ding.
      Both NSD2 and GSPT1 represent compelling targets for anticancer drug discovery. Herein, we carried out single-atom modification of LLC0424, an NSD2 degrader with GSPT1 neosubstrate engagement, to yield two structurally analogous molecules with divergent modes of action: 424-ND, an NSD2-selective degrader, and 424-GD, a GSPT1-selective degrader. 424-ND drove selective NSD2 degradation and suppressed androgen receptor (AR) signaling in prostate cancer cells. 424-GD induced selective degradation of GSPT1 and upregulated the integrated stress response markers ATF4 and ATF3. Biolayer interferometry revealed distinct ternary complex cooperativity profiles in the presence of NSD2 or GSPT1, which directly correlate with the observed biased degradation activity. Molecular dynamics and metadynamics simulations showed that the compounds adopt distinct low-energy conformational ensembles with different spatial orientations, likely underlying their divergent cooperativity and selectivity. These findings demonstrate that minimal structural alteration permits precision control over degrader target selectivity while furnishing selective chemical probes for NSD2 and GSPT1.
    Keywords:  GSPT1; NSD2; minimal structural change; selectivity; targeted protein degradation
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c01678
  43. ACS Chem Biol. 2026 Sep 18. 21(9): 2298-2305
    Deubiquitinase-Targeting Chimera (DUBTAC)-Enhanced Mammalian Expression System for Efficient Recombinant Protein Expression.
    Ruhu Zheng, Xuan Zhao, Qiushuang Zhang, Yicong Dai, Xucong Teng, Jinghong Li.
      Overexpression of exogenous proteins in mammalian cells frequently saturates the endogenous folding and quality control machinery, resulting in their recognition as misfolded substrates, subsequent polyubiquitination, and rapid degradation by the 26S proteasome. This cellular bottleneck directly constrains recombinant protein yields and remains a major challenge in biopharmaceutical production. To address this limitation, we developed a deubiquitinase-targeting chimera (DUBTAC)-enhanced mammalian expression system designed to selectively stabilize recombinant proteins. In this platform, the target protein is genetically fused to cellular retinoic acid-binding protein 1 (CRABP1), while a SNAP-tagged deubiquitinase (UCHL1-SNAP) is co-expressed. Upon administration of the heterobifunctional small molecule BG-ATRA, which simultaneously engages the SNAP tag and CRABP1, the deubiquitinase is recruited in proximity to the target protein. This induced proximity enables the enzymatic removal of degradation-linked ubiquitin chains, thereby shielding the recombinant protein from proteasomal destruction and extending its intracellular half-life. We demonstrated that this system significantly increased the yields of three structurally and functionally diverse recombinant proteins─thrombopoietin (TPO), osteoprotegerin (OPG), and vitronectin (VN)─by 2.6- to 3.1-fold in HEK293F suspension cells. Importantly, the enhanced production was achieved without compromising the biological activity of the purified proteins. This DUBTAC-based approach thus offers a robust, generalizable platform for boosting recombinant protein production in mammalian expression systems.
    DOI:  https://doi.org/10.1021/acschembio.6c00465
  44. Cell Mol Life Sci. 2026 Jul 22. pii: 386. [Epub ahead of print]83(1):
    Metformin improves mitophagy-related pathways and mitochondrial-lysosomal homeostasis in chromosome 21 trisomic fibroblasts.
    Nunzia Mollo, Rosalba Natale, Morena D'Ariano, Simona Coppola, Daniele Di Meglio, Adriana Limone, Gaetano Calì, Claudia D'Agostino, Nunzia Pastore, Daniela Sarnataro, Simona Paladino, Anna Conti, Lucio Nitsch, Antonella Izzo.
      Mitochondrial dysfunction is a core cellular abnormality in Down syndrome (DS), yet the mechanisms underlying impaired mitochondrial quality control remain poorly defined. Here, we provide an integrated characterization of the autophagy-mitophagy-lysosome axis in human trisomic fetal fibroblasts (DS-HFFs). We show that trisomic cells display a paradoxical combination of elevated basal autophagy/mitophagy-related markers and defective mitochondrial clearance, indicative of a saturated and inefficient quality control system. DS-HFFs exhibit increased steady-state levels of PINK1, PARKIN, OPTN, NDP52, LC3-II, and p62, accumulation of autophagic vacuoles, reduced autophagic flux, and impaired delivery of mitochondria to lysosomes. We further demonstrate that metformin alleviates the saturation of the autophagy-mitophagy pathway by modulating multiple components of the mitochondrial quality control pathway, including attenuation of mTOR-associated signaling, enhancement of autophagic flux and normalization of mitophagy-related protein levels. Crucially, metformin increases mitochondria-lysosome association and rescues lysosomal degradative competence as shown by increased Dq-BSA activity, and increased maturation of Cathepsin D. Together, our findings support mitophagy inefficiency due to pathway saturation as a key pathogenetic mechanism in trisomic cells and identify metformin as a pharmacological tool capable of relieving the proteostatic overload intrinsic to trisomy 21. More broadly, these results align with a model in which aneuploidy imposes a chronic proteostatic burden that compromises organelle quality control.
    Keywords:  Metformin; Mitochondrial quality control; Mitophagy; PINK1-PARKIN pathway; Trisomy 21
    DOI:  https://doi.org/10.1007/s00018-026-06355-2
  45. Cell Chem Biol. 2026 Oct 21. pii: S2451-9456(26)00369-7. [Epub ahead of print]
    Proteasome inhibition bidirectionally regulates ferroptosis sensitivity.
    Magdalena B Murray, Rishi Upadhyay, Krystina J Szylo, Aastha Gautam, Judith Goncalves, Giovanni Forcina, Ananya Vinayak, Onn Brandman, Scott J Dixon.
      Ferroptosis is a non-apoptotic cell death mechanism whose fundamental regulation continues to be elucidated. The proteasome is an essential multiprotein complex important for protein turnover. How proteasome function regulates ferroptosis is difficult to study given that proteasome inhibition causes apoptosis. Here, we isolated the effects of proteasome inhibition on ferroptosis by combining small molecule cell death inducers, pathway-specific cell death inhibitors, and direct cell death imaging. We find that proteasome inhibition enhances sensitivity to ferroptosis induced by glutathione peroxidase 4 (GPX4) inhibition while simultaneously promoting resistance to ferroptosis induced by system xc- inhibition. Sensitization to GPX4 inhibition requires protein synthesis but not the apoptosis execution machinery and is opposed by the activating transcription factor 4 (ATF4) stress response pathway. These findings establish proteasome-mediated protein turnover as a context-dependent regulator of ferroptosis and identify protein synthesis and ATF4 as key determinants of GPX4 inhibitor sensitivity.
    Keywords:  ATF4; Necrosis; cancer; iron metabolism; lipid peroxidation; oxidative stress; protein synthesis; ubiquitination
    DOI:  https://doi.org/10.1016/j.chembiol.2026.09.020
  46. Biochemistry. 2026 Oct 20. 65(20): 3144-3150
    mRNA Structure Regulates Translation at Every Step.
    Alexandra Khitun, Kevin M Weeks.
      Precise, context-sensitive control of protein synthesis is critical in eukaryotic cells, and mRNA structure has emerged as a central mechanism for achieving this control. mRNA structures influence every stage of translation. During initiation, structures within 5' untranslated regions modulate ribosome association with mRNA and the balance between translation of the main open reading frame and use of upstream or alternative start sites. During elongation, structures in the coding sequence govern ribosome pausing in ways that can either protect mRNA stability or trigger decay. During termination, structures downstream of primary stop codons promote readthrough to generate protein isoforms in a tissue-specific manner. mRNA structures are remodeled by helicase expression, post-transcriptional modifications, and translational programming to provide additional layers of regulation. We review recent advances illuminating diverse mechanisms by which RNA structure modulates translation.
    DOI:  https://doi.org/10.1021/acs.biochem.6c00561
  47. Biochem Biophys Res Commun. 2026 Oct 20. pii: S0006-291X(26)01542-1. [Epub ahead of print]840 154776
    CHK1 phosphorylates TRIM28 at Ser473 to drive NLRP3 inflammasome assembly and inflammatory responses.
    Peng-Peng Zhu, Xing-Xing Chen, Xia-Ying Chen, Yu Yu.
      The NLRP3 inflammasome is a central player in innate immunity and is implicated in various inflammatory diseases, but its kinase-mediated regulatory networks remain incompletely defined. Here, we identify CHK1 as a positive regulator of NLRP3 inflammasome activation. Pharmacological inhibition or siRNA-mediated knockdown of CHK1 suppressed NLRP3-dependent caspase-1 activation, IL-1β secretion, and pyroptosis, without affecting AIM2 or NLRC4 inflammasomes. CHK1 promoted NLRP3 oligomerization and ASC speck formation in a kinase activity-dependent manner. Mechanistically, CHK1 phosphorylated the E3 SUMO ligase TRIM28 at Ser473. This phosphorylation enhanced NLRP3 protein stability and SUMOylation. CHK1 inhibition alleviated LPS-induced systemic inflammation in vivo. Our findings reveal a CHK1-TRIM28 axis that selectively drives NLRP3 inflammasome activation and suggest CHK1 as a potential therapeutic target for NLRP3-driven pathologies.
    Keywords:  CHK1; Inflammation; NLRP3 inflammasome; Phosphorylation; SUMOylation; TRIM28
    DOI:  https://doi.org/10.1016/j.bbrc.2026.154776
  48. RSC Med Chem. 2026 Oct 08.
    First demonstration of benzosultam CRBN ligand-mediated PROTACs for BTK and BRD4 degradation.
    Hoyeong Park, Moonjung Jeun, Ji U Choi, Yeayoung Bang, Chi Hoon Park, Pilho Kim.
      Proteolysis-targeting chimeras (PROTACs) represent a promising therapeutic approach for degrading disease-relevant proteins through the ubiquitin-proteasome system. Among the various E3 ligases employed, cereblon (CRBN) has been the most widely used in PROTAC preparation. However, currently available CRBN ligands often lack sufficient selectivity, as they can trigger off-target protein degradation, such as Sal-like protein 4 (SALL4), which is implicated in teratogenic toxicities. In this study, benzosultam-based CRBN ligands were utilized to prepare PROTACs targeting BRD4 and BTK. Among the PROTACs synthesized, 10a induced efficient degradation of BRD4, while 14a effectively degraded BTK in TMD-8 cells, showing superior or comparable potency to the known compounds ARV-825 and MT-802, respectively. Furthermore, targeted protein degradation translated into potent anti-proliferative activities in TMD-8 cells, with 10a exhibiting robust cell growth inhibition. In contrast to ARV-825 and MT-802, 10a and 14a showed negligible SALL4 degradation, suggesting a favorable off-target safety profile of benzosultam CRBN ligands. These findings underscore the potential of the benzosultam scaffold as a promising and selective alternative for CRBN-mediated targeted protein degradation.
    DOI:  https://doi.org/10.1039/d6md00815a
  49. J Med Chem. 2026 Sep 24. 69(18): 21381-21397
    A 2-in-1 Strategy for the Discovery of Compact HDAC8 Protac Degraders.
    Yi Liu, Nikee Awasthee, Yufeng Xiao, Seth Hale, Wanyi Hu, Michael Y He, Abhishek Gour, Wenlin Yang, Abhisheak Sharma, Robert Kridel, Daiqing Liao, Guangrong Zheng.
      Proteolysis-targeting chimera (PROTAC) technology has emerged as a powerful therapeutic strategy in drug discovery. Conventional PROACs are heterobifunctional molecules composed of two distinct ligands that independently bind to a protein of interest (POI) and an E3 ligase. However, their inherently large molecular size often leads to suboptimal drug-like properties. In this study, we report a "2-in-1" PROTAC design strategy for developing more compact HDAC8 degraders by integrating the CRBN-recruiting ligand into the capping group of an HDAC8 warhead, thereby enabling a single structural motif to engage both HDAC8 and CRBN. Compared to our first generation HDAC8 degrader YX862, the new degraders exhibit improved selectivity, reduced molecular weight, improved overall drug-like properties, and, importantly, potent HDAC8 degradation in vivo. These findings highlight the therapeutic potential of this new class of HDAC8 degraders, and demonstrate a conceptual framework for integrating E3 ligase recruitment and target engagement into a more efficient and compact PROTAC design.
    Keywords:  2-in-1 strategy; HDAC8 degraders; PROTAC; cereblon; compact PROTAC design
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c01636
  50. J Med Chem. 2026 Sep 24. 69(18): 21421-21439
    Development of Isoform-Selective GRP78 Inhibitors from a Direct-to-Biology Strategy.
    Xiaoyi Zhu, Qiu Li, Ke Wang, Haofeng Ye, Carlee A Trindl, Lewis S Alexander, Yongyi Wei, Aikseng Ooi, Donna D Zhang, Eli Chapman.
      The development of isoform-selective HSP70 inhibitors remains challenging due to the high conservation of this chaperone family. Continuing our efforts to target the peptide-binding pocket within the substrate-binding domain (SBD) of GRP78 (BiP/HSPA5), we identified compound 12 using a Direct-to-Biology (D2B) strategy. Biochemical, biophysical, and cellular characterization showed that 12 directly engages the GRP78 peptide-binding pocket, selectively binds GRP78 over other tested HSP70 isoforms, and potently kills A549 lung cancer cells while showing minimal activity in other tested lung cancer cell lines. Cellular thermal shift assay (CETSA) demonstrated GRP78 engagement in cells, and unfolded protein response (UPR) signaling analysis further showed that 12 modulates GRP78-related stress-response pathways, supporting its functional engagement of GRP78. Collectively, compound 12 represents a well-characterized, isoform-selective, cell active, and cell selective GRP78 inhibitor, providing a valuable chemical probe for dissecting GRP78 biology and a promising starting point for the development of GRP78-targeted therapeutics.
    Keywords:  Chaperone; GRP78; HSP70; lung cancer
    DOI:  https://doi.org/10.1021/acs.jmedchem.6c01794
  51. J Cell Biol. 2026 Nov 02. pii: e202610007. [Epub ahead of print]225(11):
    Swollen lysosomes grab Rabs for a CASM-free route to LRRK2 activation.
    Suzanne R Pfeffer.
      Multiple lysosomal stresses activate Parkinson's-linked LRRK2 kinase, and these involve the so-called "CASM" pathway to help recruit LRRK2 to lysosome surfaces. Clegg et al. (https://doi.org/10.1083/jcb.202511137) show that LRRK2, activated upon lysosome swelling caused by PIKfyve inhibition, instead relies solely on Rab GTPase binding for lysosome localization and activation.
    DOI:  https://doi.org/10.1083/jcb.202610007
  52. ACS Synth Biol. 2026 Sep 18. 15(9): 3795-3806
    Artificial Initiation Codons and Engineered Initiator tRNAs Enable N-Terminal Noncanonical Amino Acid Incorporation in Cell-Free Translation Systems While Retaining Native Methionine Incorporation.
    Haruyuki Furukawa, Yasunori Okamoto, Naohiro Terasaka.
      Noncanonical amino acid (ncAA) incorporation at the protein N-terminus enables defined protein functionalization. However, initiation-based ncAA incorporation systems generally suppress the native methionine pathway, limiting their use for proteins containing internal methionine residues. Here, we developed an orthogonal initiation system for N-terminal ncAA incorporation in cell-free translation systems while retaining native methionine incorporation. We profiled background initiation from all 64 codons in cell-free translation systems and identified low-background artificial initiation codons. Engineered initiator tRNAs were designed to introduce ncAA at the protein N-terminus using artificial initiation codons. This system enabled efficient incorporation of N-biotinyl-l-phenylalanine into protein, reaching over 90% incorporation. This system was further extended to p-azido-l-phenylalanine and to an Escherichia coli extract-based cell-free translation system. Finally, N-biotinylated proteins synthesized in this system were utilized for purification-free biolayer interferometry analysis. This work establishes an orthogonal initiation strategy for N-terminal protein functionalization while preserving the native methionine incorporation.
    Keywords:  PURE system; biolayer interferometry; cell-free translation; de novo protein design; genetic code reprogramming; noncanonical amino acid
    DOI:  https://doi.org/10.1021/acssynbio.6c00473
  53. Autophagy. 2026 Oct 20.
    A host-virus arms race over FAM134B in African swine fever virus infection.
    Tao Wang, Rui Luo, Ruojia Huang, Yuan Sun, Hua-Ji Qiu.
      Although reticulophagy, the selective autophagy of the endoplasmic reticulum (ER), restricts several RNA viruses, whether this pathway constrains DNA virus infection remains unknown. Recently, we found that FAM134B (family with sequence similarity 134 member B), an ER-resident cargo receptor that mediates reticulophagy, restricts African swine fever virus (ASFV), a large cytoplasmic DNA virus, by targeting the major capsid proteins p72 and pA137R for lysosomal degradation, thereby blocking capsid assembly at perinuclear viral factories. ASFV counters this restriction through the virulence factor pMGF300-2 R encoded by the MGF300-2 R gene of ASFV, which binds to FAM134B, recruits LC3B (microtubule-associated protein 1 light chain 3 beta), an ATG8 (autophagy-related protein 8) family member, via the C-terminal LC3-interacting region (LIR) motif, and directs FAM134B into autophagic degradation. Deletion of the MGF300-2 R gene in the ASFV genome restores FAM134B abundance, reduces viral replication, and attenuates virulence in pigs. These findings establish reticulophagy as a previously unrecognized antiviral barrier against a large DNA virus and reveal a host-virus arms race centered on the reticulophagy receptor.
    Keywords:  African swine fever virus; FAM134B; pMGF300-2R; reticulophagy; viral factories
    DOI:  https://doi.org/10.1080/15548627.2026.2751870
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