bims-proteo 2026-01-11 papers

bims-proteo

Biomed News

on Proteostasis

Issue of 2026–01–11
forty-two papers selected by
Eric Chevet, INSERM

The role of ER-associated degradation and ER-phagy in health and disease.
The ATG8 E3-like ligases sense lysosomal damage and initiate ESCRT-mediated membrane repair.
CBL ubiquitin ligase targets translation as a degrader E3.
Bacterial ubiquitin ligase engineered for small molecule and protein target identification.
Rsp5/NEDD4 and ESCRT regulate TDP-43 toxicity and turnover via an endolysosomal clearance mechanism.
The mechanistic basis and cellular functions of UFMylation.
Optogenetic Proximity Labeling Maps Spatially Resolved Mitochondrial Surface Proteomes and a Locally Regulated Ribosome Pool.
Membrane-protein-mediated phase separation orchestrates organelle contact sites.
Linear ubiquitination triggers Amph-mediated T-tubule biogenesis.
PARG regulates the proteasomal degradation of TARG1.
Variant-specific interaction of kinectin 1 with the multi-tRNA synthetase complex regulates ER sheet organization.
Rapid activation of p62 body-mediated autophagy in human cells under hyperosmotic stress.
The ubiquitin E3 ligase HRD1 restricts hepatic lipid metabolism by suppressing PPARα-driven m6A RNA modification.
IRE1 signaling in osteoprogenitors augments β-catenin activity and physiologic bone accrual.
The many faces of p97/Cdc48 in mitochondrial homeostasis.
CUL4A-DDB1-DCAF10 is an N-recognin for N-terminally acetylated Src kinases.
TRIM2 E3 ligase substrate discovery reveals zinc-mediated regulation of TMEM106B in the endolysosomal pathway.
Tuning the open-close equilibrium of Cereblon with small molecules influences protein degradation.
Lysine deficiency within a conserved lysine desert is critical for EEL-1/HUWE1 to support ubiquitin proteasome system function.
Mitochondrial presequences harbor variable strengths to maintain organellar function.
TBK1 orchestrates autophagy and endo-lysosomal pathways in human neurons.
A Rab1 interactome illuminates a dual role in autophagy and membrane trafficking.
Mechanistic insights into recruitment and regulation of the RNA helicase UPF1 in replication-dependent histone mRNA decay.
Measuring lysosome damage and lysophagy in vivo.
Unraveling Stress-Adaptation Pathways in Cancer: Functional Dissection Through CRISPR-Based Genetic Screens.
LAMP2A regulates endosomal protein composition and membrane identity in exosome biogenesis.
Monovalent pseudo-natural products supercharge degradation of IDO1 by its native E3 KLHDC3.
Ubiquitination-directed cytosolic DNA degradation governs cGAS-STING-mediated immune response to DNA damage.
Coupling the MAPK Slt2/ERK1 Pathway and IRE1-driven UPR Through Transcription Factor Rlm1/MEF2.
Endothelial IRE1α promotes thrombospondin-1 mRNA decay and supports metabolic stress adaptation of pancreatic islets.
A prelimbic molecular clock of protein synthesis for memory persistence.
Computational design of conformation-biasing mutations to alter protein functions.
Characteristics of endoplasmic reticulum stress changes during the differentiation of adipose-derived stromal cells into neurons.
SARS-CoV-2 and MERS-CoV disrupt host protein synthesis via nsp1 with differential effects on the integrated stress response.
A survey of predicted protein-protein interactions involving disordered regions in humans.
Ubiquitination and autophagy in host-pathogen interactions: from immune surveillance to therapeutic targeting.
Dynamins maintain nuclear envelope homeostasis and genome stability.
Reshaping cancer cell plasticity by P-body dynamics and protein translation.
Membrane editing with proximity labeling reveals regulators of lipid homeostasis.
Eukaryotic initiation factor 3d Regulates Context-Dependent Pain Hypersensitivity Through the Integrated Stress Response.
Identification of aryl hydrocarbon receptor as a functional target that enhances astrocytic ApoE secretion.
A mechanism for the disrupted redox regulation of vascular contractility during aging.

Signal Transduct Target Ther. 2026 Jan 05. 11(1): 7

The role of ER-associated degradation and ER-phagy in health and disease.

Young Joo Jeon, Ze'ev A Ronai.

The endoplasmic reticulum (ER) is a major cellular organelle for the synthesis and folding of secretory and transmembrane proteins, whose proper function underpins organellar homeostasis, proper tissue function, and organismal physiology. Protein quality control (PQC) systems at the ER include the unfolded protein response (UPR), ER-associated degradation (ERAD), and ER-phagy, which monitor ER homeostasis and contribute to protein refolding, sequestration, or degradation. ERAD prevents the accumulation of misfolded or orphan proteins that would otherwise be toxic. By controlling the degradation of these proteins, ERAD performs a core function in governing adaptation to proteotoxic stress. ERAD also regulates the abundance of folding-competent proteins as a means to fine-tune key physiological processes. Among its complex regulatory activities, ERAD controls cellular processes such as lipid homeostasis, calcium flux, and cell fate decisions, which are all required for the maintenance of organelle homeostasis. Highlighting its importance, dysregulation of ERAD often results in devastating diseases. Here, we discuss the molecular and mechanistic understanding of protein quality and quantity control by ERAD and its interface with ER-phagy, as well as other cellular stress programs. The implications of ERAD and its associated regulatory arms for cellular homeostasis, its effects on health and disease, and current therapeutic approaches are discussed.

DOI: https://doi.org/10.1038/s41392-025-02501-7
EMBO J. 2026 Jan 03.

The ATG8 E3-like ligases sense lysosomal damage and initiate ESCRT-mediated membrane repair.

Dale P Corkery, Deerada Wijayatunga, Benedita K L Feron, Laura K Herzog, Anastasia Knyazeva, Yao-Wen Wu.

  After damage from pathogenic, chemical or physical stress, endolysosomal membranes are repaired and resealed by the endosomal sorting complex required for transport (ESCRT) machinery, but how this membrane damage is sensed and translated into ESCRT recruitment is poorly understood. Here, we identify the two ATG8 E3-like ligases, ATG16L1 and TECPR1, as ion-dependent catalysts for ESCRT recruitment to damaged lysosomal membranes. Leakage from perforated lysosomes induces the proton sensitive V-ATPase-dependent recruitment of ATG16L1-ATG5-ATG12 complexes, or the calcium-sensitive sphingomyelin-dependent recruitment of TECPR1-ATG5-ATG12 complexes. In both cases, the E3-like complex-dependent ATG5-ATG12 conjugate is required for ESCRT recruitment to the damaged membrane, and stabilization of the ESCRT machinery. Collectively, this study establishes the ATG8 E3-like ligases as membrane damage sensors for ESCRT-mediated membrane repair.

Keywords:  ATG8 E3-like Ligases; CASM; ESCRT; Lysosomal Membrane Integrity; Membrane Damage Sensor

DOI:  https://doi.org/10.1038/s44318-025-00672-1
Chem Sci. 2025 Dec 26.

CBL ubiquitin ligase targets translation as a degrader E3.

Alice T Wicks, Lori Buetow, Toshiyasu Suzuki, Tobias Schmidt, Sergio Lilla, Abigail Macmillan-Jones, Jennifer Turney, Andrea Gohlke, Martin Bushell, Andreas K Hock, Danny T Huang.

Proteolysis Targeting Chimeras (PROTACs) are heterobifunctional molecules that recruit an ubiquitin ligase (E3) and a neo-substrate into a ternary complex, enabling selective protein degradation. Despite the presence of over 600 E3s, only a handful are utilised in PROTAC application, potentially limiting the number of druggable targets. Here, we investigate whether Casitas B-cell lymphoma (CBL) can be harnessed as a degrader E3 to promote ubiquitination and degradation of the eukaryotic translation initiation factor 4E (eIF4E). Using a selective CBL binding peptide, CBLock, we demonstrate that CBL facilitates the ubiquitination of CBLock-eIF4E fusion in cells and in in vitro reconstituted assays. We further developed peptidic PROTACs, termed eIFTerminators, by linking CBLock to an eIF4E-binding peptide. Among them, eIFTerminator4 rapidly eliminates endogenous eIF4E via both lysosomal and proteasomal pathways. Unexpectedly, eIFTerminator4 also caused a decrease in eIF4A and eIF4G levels, leading to a reduction in overall protein translation in cells. Our findings establish proof-of-concept that CBL can function as a degrader E3, expanding the arsenal of E3s available for targeted protein degradation in combating challenging drug targets.

DOI: https://doi.org/10.1039/d5sc06141e
EMBO J. 2026 Jan 03.

Bacterial ubiquitin ligase engineered for small molecule and protein target identification.

James S Ye, Abir Majumdar, Brenden C Park, Miles H Black, Ting-Sung Hsieh, Adam Osinski, Kelly A Servage, Kartik Kulkarni, Jacinth Naidoo, Neal M Alto, Margaret M Stratton, Dominique Alfandari, Joseph M Ready, Krzysztof Pawłowski, Diana R Tomchick, Vincent S Tagliabracci.

  The Legionella SidE effectors ubiquitinate host proteins independently of the canonical E1-E2 cascade. Here we engineer the SidE ligases to develop a modular proximity ligation approach for the identification of targets of small molecules and proteins, which we call SidBait. We validate the method with known small molecule-protein interactions and use it to identify CaMKII as an off-target interactor of the breast cancer drug ribociclib. Structural analysis and activity assays confirm that ribociclib binds the CaMKII active site and inhibits its activity. We further customize SidBait to identify protein-protein interactions and discover the F-actin capping protein (CapZ) as a target of the Legionella effector RavB during infection. Structural and biochemical studies indicate that RavB allosterically binds CapZ and decaps actin, thus functionally mimicking eukaryotic CapZ interacting proteins. Collectively, our results establish SidBait as a reliable tool for identifying targets of small molecules and proteins.

Keywords:   Legionella ; Actin Capping; Kinase Inhibitor; Target Identification

DOI:  https://doi.org/10.1038/s44318-025-00665-0
J Cell Biol. 2026 Feb 02. pii: e202212064. [Epub ahead of print]225(2):

Rsp5/NEDD4 and ESCRT regulate TDP-43 toxicity and turnover via an endolysosomal clearance mechanism.

Aaron Byrd, Lucas J Marmorale, Sophia Marcinowski, Megan M Dykstra, Vanessa Addison, Sami J Barmada, J Ross Buchan.

A pathological hallmark in >97% of amyotrophic lateral sclerosis (ALS) cases is the cytoplasmic mislocalization and aggregation of TDP-43, a nuclear RNA-binding protein, in motor neurons. Driving clearance of cytoplasmic TDP-43 reduces toxicity in ALS models, though how TDP-43 clearance is regulated remains controversial. We conducted an unbiased yeast screen using high-throughput dot blotting to identify genes that affect TDP-43 levels. We identified ESCRT complex genes, which induce membrane invagination (particularly at multivesicular bodies; MVBs) and genes linked to K63 ubiquitination (particularly cofactors of the E3 ubiquitin ligase Rsp5; NEDD4 in humans), as drivers of TDP-43 endolysosomal clearance. TDP-43 colocalized and bound Rsp5/NEDD4 and ESCRT proteins, and perturbations to either increased TDP-43 aggregation, stability, and toxicity. NEDD4 also ubiquitinates TDP-43. Lastly, TDP-43 accumulation induces giant MVB-like vesicles, within which TDP-43 accumulates in a NEDD4-dependent manner. Our studies shed light on endolysosomal-mediated cytoplasmic protein clearance, a poorly understood proteostasis mechanism, which may help identify novel ALS therapeutic strategies.

DOI: https://doi.org/10.1083/jcb.202212064
Nat Rev Mol Cell Biol. 2026 Jan 09.

The mechanistic basis and cellular functions of UFMylation.

Masaaki Komatsu, Nobuo N Noda, Toshifumi Inada.

UFMylation is a ubiquitin-like post-translational modification that has a central role in ribosome-associated quality control at the endoplasmic reticulum (ER-RQC). Through a dedicated enzymatic cascade, UFM1 is conjugated to select substrates, notably the 60S ribosomal subunit protein RPL26, to maintain endoplasmic reticulum and ribosomal integrity under cellular stress. This Review focuses on the structural and mechanistic basis of UFMylation in ER-RQC and its contribution to proteostasis. Although recent studies have identified a growing number of putative UFM1-modified proteins across diverse cellular pathways, the physiological importance of many of these substrates remains unclear. We highlight both the emerging functional breadth of UFMylation and the need for caution in interpreting substrate relevance. UFMylation is increasingly linked to disease, including neurodevelopmental disorders and cancer, underscoring its biological importance. Together, these findings position UFMylation as a key regulatory system connecting endoplasmic reticulum function to broader stress responses.

DOI: https://doi.org/10.1038/s41580-025-00944-y
bioRxiv. 2025 Dec 23. pii: 2025.12.21.693523. [Epub ahead of print]

Optogenetic Proximity Labeling Maps Spatially Resolved Mitochondrial Surface Proteomes and a Locally Regulated Ribosome Pool.

Chulhwan S Kwak, Zehui Du, Joseph S Creery, Emily M Wilkerson, Michael B Major, Joshua E Elias, Xinnan Wang.

Outer mitochondrial membranes (OMM) function as dynamic hubs for inter-organelle communication, integrating bidirectional signals, and coordinating organelle behavior in a context-dependent manner. However, tools for mapping mitochondrial surface proteomes with high spatial and temporal resolution remain limited. Here, we introduce an optogenetic proximity labeling strategy using LOV-Turbo, a light-activated biotin ligase, to profile mitochondrial surface proteomes with improved precision, temporal control, and reduced background. By fusing LOV-Turbo to a panel of variants of an OMM-anchored protein, Miro1, we generate spatially distinct baits that resolve modular architectures and regulatory states of the OMM proteomes across diverse conditions, a database we name MitoSurf. Building on this proteomic map, we present RiboLOOM, a platform that defines LOV-Turbo labeled ribosomes and their bound mRNAs at the mitochondrial surface. MitoSurf and RiboLOOM uncover a spatially distinct ribosome pool at the OMM that is maintained by Miro1, enabling local mRNA engagement and translation of mitochondria-related proteins. These findings establish Miro1 as a key organizer of mitochondrial protein biogenesis through spatial confinement of surface-associated ribosomes. Our platform reveals an uncharted layer of mitochondrial surface biology and provides a generalizable strategy to dissect dynamic RNA-protein-organelle interfaces in living cells.

DOI: https://doi.org/10.64898/2025.12.21.693523
Mol Cell. 2026 Jan 08. pii: S1097-2765(25)00980-3. [Epub ahead of print]86(1): 135-149.e9

Membrane-protein-mediated phase separation orchestrates organelle contact sites.

Christian Hoffmann, Takahiro Nagao, Taka A Tsunoyama, Johannes Vincent Tromm, Chinyere Logan, Koki Nakamura, Han Wang, Frans Bianchi, Geert van den Bogaart, Akihiro Kusumi, Yusuke Hirabayashi, Dragomir Milovanovic.

  Mitochondria and the endoplasmic reticulum (ER) contain large areas that are in close proximity. Yet the mechanism of how these inter-organellar adhesions are formed remains elusive. Tight functional connections, termed "membrane contact sites," assemble at these areas and are essential for exchanging metabolites and lipids between the organelles. Recently, the ER-resident protein PDZ domain-containing protein 8 (PDZD8) was identified as a tether between the ER and mitochondria or late endosomes/lysosomes. Here, we show that PDZD8 can undergo phase separation via its intrinsically disordered region (IDR). Endogenously labeled PDZD8 forms condensates on membranes both in vitro and in mammalian cells. Electron microscopy analyses indicate that the expression of full-length PDZD8 rescues the decrease in inter-organelle contacts in PDZD8 knockout cells but not PDZD8 lacking its IDR. Together, this study identifies that PDZD8 condensates at the lipid interfaces act as an adhesive framework that stitches together the neighboring organelles and supports the structural and functional integrity of inter-organelle communication.

Keywords:  PDZD8; biomolecular condensates; endoplasmic reticulum; liquid-liquid phase separation; membrane contact sites; mitochondria

DOI:  https://doi.org/10.1016/j.molcel.2025.12.006
Sci Adv. 2026 Jan 09. 12(2): eady4934

Linear ubiquitination triggers Amph-mediated T-tubule biogenesis.

Kohei Kawaguchi, Yutaro Hama, Harunori Yoshikawa, Kohei Nishino, Kazuki Morimoto, Tsuyoshi Nakamura, Michiko Koizumi, Yuriko Sakamaki, Kota Abe, Soichiro Kakuta, Koichiro Ichimura, Fumiyo Ikeda, Hidetaka Kosako, Naonobu Fujita.

Transverse tubules (T-tubules) are invaginations of the muscle plasma membrane that facilitate rapid transmission of action potentials, ensuring synchronized muscle contraction. Despite their essential role in muscle physiology, the mechanisms underlying T-tubule formation remain elusive. Here, we identify LUBEL/RNF31, a ubiquitin E3 ligase responsible for linear (M1-linked) ubiquitination, as a key regulator of T-tubule biogenesis in Drosophila. Loss of LUBEL leads to Amphiphysin (Amph)-positive membrane sheets instead of tubular networks. The ubiquitin ligase activity of LUBEL and direct interaction with Amph, a BAR domain protein involved in membrane tubulation, are crucial for proper T-tubule morphology. LUBEL and M1-linked ubiquitin chains assemble into puncta on membranes through multivalent interactions, facilitating Amph-mediated tubulation. Notably, the Amph-LUBEL/RNF31 interaction is evolutionarily conserved across species, underscoring a fundamental role for linear ubiquitination in membrane remodeling. Our findings uncover an unexpected function of linear ubiquitination in membrane deformation driven by BAR proteins.

DOI: https://doi.org/10.1126/sciadv.ady4934
Cell Rep. 2026 Jan 06. pii: S2211-1247(25)01561-X. [Epub ahead of print]45(1): 116789

PARG regulates the proteasomal degradation of TARG1.

Joséphine Groslambert, Sara C Buch-Larsen, Ivo A Hendriks, Robert Kurzbauer, Jonas D Elsborg, Chatrin Chatrin, Thomas Agnew, Callum Henfrey, Michael Tellier, Evgeniia Prokhorova, Song My Hoang, Jonathan Barosso-Gonzalez, Roderick J O'Sullivan, Tim Clausen, Michael L Nielsen, Ivan Ahel.

  ADP-ribosylation (ADPr) is a reversible modification of macromolecules critical for the regulation of genome stability, stress responses, and proteostasis. While the roles of ADPr transferases such as PARP1/2 and TNKS1/2 are well established, the functions and regulatory mechanisms of ADPr hydrolases are still poorly understood. Here, we identify a function of the poly(ADP-ribose) glycohydrolase PARG in regulating protein degradation. Using quantitative proteomics, we show that PARG inhibition depletes protein levels of the mono-ADPr hydrolase TARG1. We demonstrate that this TARG1 depletion is both PAR and proteasome dependent and identify the E3 ubiquitin ligases HUWE1 and TRIP12 as mediators of this process. Our findings establish TARG1 as a substrate of PAR-dependent protein degradation and uncover a PARG-dependent mechanism controlling its stability. This work highlights an interplay between the two ADP-ribosyl hydrolases, with implications for the refinement of PARG-targeted therapeutic strategies.

Keywords:  ADP-ribosylation; CP: molecular biology; DNA damage; PARP; proteasomal degradation; ubiquitylation

DOI:  https://doi.org/10.1016/j.celrep.2025.116789
iScience. 2026 Jan 16. 29(1): 114303

Variant-specific interaction of kinectin 1 with the multi-tRNA synthetase complex regulates ER sheet organization.

Masaki Hosogane, Sue-Yi Siao, Atsushi Hatano, Xiaoxin Huang, Yuichi Shichino, Yasuaki Watanabe, Shintaro Iwasaki, Masaki Matsumoto, Keiko Nakayama.

  Kinectin 1 (KTN1) is an integral endoplasmic reticulum (ER) sheet protein involved in ER organization and translation elongation. Alternative splicing introduces sequence diversity into the cytosolic region of KTN1; however, the functional significance of these variants has remained unclear. Here, we show that the multi-tRNA synthetase complex (MSC), composed of eight aminoacyl-tRNA synthetases and three nonenzymatic proteins, specifically interacts with KTN1 in a manner dependent on the alternative exon V2 and glutamine-tRNA synthetase (QARS). Using V2 exon-specific knockout cells and KTN1 knockout cells with variant-specific rescue, we found that the V2 exon is required for KTN1-mediated recruitment of the MSC to the ER, where it facilitates the formation of rough ER stacks. These findings define a variant-specific role for KTN1 in anchoring the MSC to the ER and suggest that this interaction underlies a noncanonical function of the MSC in regulating ER sheet organization.

Keywords:  Biochemistry; Cell biology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2025.114303
Commun Biol. 2026 Jan 05. 9(1): 1

Rapid activation of p62 body-mediated autophagy in human cells under hyperosmotic stress.

Naoki Tamura, Satoshi Waguri.

The autophagy receptor p62 is degraded via autophagy under hyperosmotic stress, but whether this involves the formation of biomolecular condensates (p62 bodies) remains unclear. Using human cells, we found that p62 bodies formed within 1 minute of hyperosmotic stress, and increased with stress severity. They formed faster and under milder stress than stress granules, a classic condensate, and exhibited liquid-like properties. Unlike stress granules, p62 bodies frequently colocalized with LC3 and WIPI-2, and were degraded via autophagy. Correlative light and electron microscopy revealed that these p62 bodies were more compact than stress granules and were often associated with the autophagic isolation membrane. Autophagy receptors NBR1 and TAX1BP1, but not OPTN1 or NDP52, behaved similarly to p62, and p62 bodies preferentially contained K63-linked ubiquitin chains. p62 body formation was also observed in human epithelial organoids in association with WIPI-2. Collectively, these results indicate that p62 bodies function as a platform of degradation under hyperosmotic stress.

DOI: https://doi.org/10.1038/s42003-025-09190-6
Sci Signal. 2026 Jan 06. 19(919): eadx8300

The ubiquitin E3 ligase HRD1 restricts hepatic lipid metabolism by suppressing PPARα-driven m6A RNA modification.

Hyunbae Kim, Pattaraporn Thepsuwan, Juncheng Wei, Donghong Ju, Qi Chen, Xiaohong Zhang, Li Li, Jie Xu, Xin Tong, Shengyi Sun, Chuan He, Lei Yin, Deyu Fang, Kezhong Zhang.

Hepatic lipid metabolism is regulated by circadian rhythms and dynamically responds to nutrient availability, such that lipid synthesis, oxidation, and storage are temporally coordinated. We demonstrated that the endoplasmic reticulum (ER)-localized E3 ubiquitin ligase HRD1 stimulated lipid accumulation in the liver by decreasing the N6-methyladenosine (m6A) methylation and expression of mRNAs encoding factors involved in lipid metabolism. In mouse livers, m6A RNA modification and the expression of mRNAs encoding the m6A writer METTL14 and the m6A reader YTHDF3 were under circadian control and inversely correlated with the abundance of HRD1. m6A RNA sequencing analyses revealed that HRD1 and the m6A writer METTL14 had opposing roles in the m6A modification and expression of mRNAs encoding factors involved in fatty acid metabolism. In vivo, hepatic lipid accumulation and triglyceride amounts were decreased in mice with hepatic HRD1 deficiency fed a high-fat diet but increased in mice with hepatic METTL14 or YTHDF deficiency fed normal chow. Mechanistically, HRD1 mediated the polyubiquitination and degradation of PPARα, which transcriptionally activated METTL14 and YTHDF3 expression in the liver. Our work identifies a pathway regulated by circadian rhythms or nutrients in which HRD1 promotes the degradation of PPARα to decrease the m6A modification and expression of hepatic mRNAs encoding factors involved in lipid metabolism.

DOI: https://doi.org/10.1126/scisignal.adx8300
J Bone Miner Res. 2026 Jan 06. pii: zjag001. [Epub ahead of print]

IRE1 signaling in osteoprogenitors augments β-catenin activity and physiologic bone accrual.

Lakshmi D Kolora, Christian Melendez-Suchi, Veronica Butler, Li Han, Maria Almeida, Kartik Shankar, Douglas J Adams, Srividhya Iyer.

  The endoplasmic reticulum (ER) orchestrates the folding of the large amounts of membrane and secretory proteins that are synthesized during the process of osteogenesis. The Unfolded Protein Response (UPR) resulting from accumulation of misfolded proteins in the ER lumen either promotes or inhibits osteoblast differentiation in vitro depending on magnitude and duration. All three transducers of the UPR, namely, IRE, PERK, and ATF6 proteins, have been implicated in skeletal biology, yet their specific contribution to osteoblast differentiation and function in vivo has not been investigated systematically. Here, the skeletal consequences of deleting each of them (i.e. Ire1α, Perk, or Atf6) in the osteoblast lineage using the Osx1-Cre transgene were determined. Mice with deletion of Ire1α in Osx1+ osteoblast precursors exhibited a marked reduction in osteoblast number, bone mass, and strength. Primary bone marrow cultures of osteoprogenitors lacking Ire1α had significantly reduced proliferation, alkaline phosphatase activity, and survival. Analyses of bulk RNA-seq data revealed suppression of osteogenic signature by Ire1α deletion in Osx1+ cells and predicted suppression of β-catenin activity. Mechanistically, Ire1α augments nuclear translocation and transcriptional activity of β-catenin in Osx1+ cells. In contrast, deletion of Perk or Atf6 genes in the osteoblast lineage using the Osx1-Cre transgene did not alter bone mass or strength. Collectively, these studies demonstrate that IRE1, but not other UPR transducers, promote physiological bone accrual in part by boosting β-catenin activity in osteoprogenitors.

Keywords:  ATF6; ER stress; PERK; Unfolded Protein Response; bone formation; osteoblast lineage; β-catenin

DOI:  https://doi.org/10.1093/jbmr/zjag001
Essays Biochem. 2025 Dec 22. pii: EBC20253045. [Epub ahead of print]69(5):

The many faces of p97/Cdc48 in mitochondrial homeostasis.

Jonathan Ram, Michael H Glickman.

  Through its various roles in protein quality control, membrane dynamics, and cellular survival pathways, the AAA+ ATPase p97/valosin-containing protein emerges as a significant regulator of mitochondrial homeosta sis. This review comprehensively examines the multifaceted functions of p97 in mitochondrial biology, spanning from mitochondria-associated degradation to newly discovered functions in organellar cross-talk and disease pathogenesis. Underlying its cellular importance, p97 mutations are found in amyotrophic lateral sclerosis and frontotemporal dementia. To elucidate its mechanistic contribution to these processes, we provide a detailed table (Table 1) listing all known mitochondrial Cdc48/p97 substrates and associ ated proteins, categorized by their respective pathways. Recruitment to most of these substrates occurs by specialized adaptors, including Doa1/phospholipase A-2-activating protein, UBXD8, and UBXN1. p97 orchestrates the extraction and proteasomal degradation of outer mitochondrial membrane proteins, which are essential for maintaining mitochondrial integrity. For example, by controlling the turnover of fusion factors MFN1/2 and fission machinery, p97 regulates mitochondrial dynamics. p97 also governs apoptotic signaling through the regulated degradation of anti-apoptotic factors, such as myeloid cell leukemia-1 and VDAC, thereby modulating mitochondrial permeability. In mitophagy, p97 enables the clearance of damaged organelles by extracting ubiquitinated substrates and recruiting autophagy machinery. Beyond proteolysis, p97 facilitates recycling of endoplasmic reticulum-mitochondria contact sites through regulation of UBXD8-dependent lipid metabolism. Recent discoveries have revealed p97's involvement in pathogen host interactions and circular RNA-mediated regulation, thereby expanding our understanding of its cellular functions. The emerging picture positions p97 as an integrative hub co-ordinating mitochondrial protein homeostasis, organellar dynamics, and cell fate decisions, with therapeutic potential for metabolic and neurodegenerative disorders.

Keywords:  Cdc48; ERAD; MAD; P97; VCP; mitochondria; mitostasis; proteasome; ubiquitin

DOI:  https://doi.org/10.1042/EBC20253045
Nat Commun. 2026 Jan 03. 17(1): 132

CUL4A-DDB1-DCAF10 is an N-recognin for N-terminally acetylated Src kinases.

Nora Kremer, Franziska Mueller, Hang Nguyen, Louisa Schulz, Tanja Popp, Elena Artes, Julian Wolters, Michael Renner, Ingrid Vetter, Stefano Maffini, Maria S Robles, Andrea Musacchio, Tanja Bange.

Co-translational N-terminal modifications such as methionine excision, acetylation, and myristoylation govern protein stability, localization, and folding. Disruption can expose N-terminal degrons that trigger ubiquitin-mediated degradation, safeguarding the proteome. N-terminal acetylation usually protects proteins from degradation, but can also promote it through the Ac/N-degron pathway. Src-family kinases (SFKs), signaling enzymes implicated in tumorigenesis, require N-terminal myristoylation for function. Using peptide pull-downs, mass spectrometry, and AlphaFold 3 predictions, we identify DCAF10 as the E3 ligase substrate receptor for alternatively N-terminally acetylated SFKs. Combining siRNA-mediated knockdown and CRISPR/Cas9-mediated knockout of endogenous Lyn with inducible Lyn-GFP variants confirms that DCAF10 regulates SFK levels by recognizing an N-terminal acetylated glycine residue. In vitro, a CUL4A-DDB1-DCAF10 complex ubiquitinates N-terminally acetylated SFKs. Thus, we define a novel N-degron pathway that monitors replacement of myristoylation by acetylation and activates degradation of SFKs upon acetylation. This mechanism may extend to other N-terminally myristoylated proteins beyond SFKs.

DOI: https://doi.org/10.1038/s41467-025-68074-9
EMBO Rep. 2026 Jan 03.

TRIM2 E3 ligase substrate discovery reveals zinc-mediated regulation of TMEM106B in the endolysosomal pathway.

Cecilia Perez-Borrajero, Frank Stein, Kristian Schweimer, Mandy Rettel, Jennifer J Schwarz, Per Haberkant, Karine Lapouge, Jesse Gayk, Thomas Hoffmann, Sagar Bhogaraju, Kyung-Min Noh, Mikhail Savitski, Julia Mahamid, Janosch Hennig.

  TRIM2 is a mammalian E3 ligase with particularly high expression in Purkinje neurons, where it contributes to neuronal development and homeostasis. The understanding of ubiquitin E3 ligase function hinges on thoroughly identifying their cellular targets, but the transient nature of signaling complexes leading to ubiquitination poses a significant challenge for detailed mechanistic studies. Here, we tailored a recently developed ubiquitin-specific proximity labeling tool to identify substrates of TRIM2 in cells. We show that TRIM2 targets proteins involved in the endolysosomal pathway. Specifically, we demonstrate using biochemical and structural studies, that TRIM2 ubiquitinates TMEM106B at lysine residues located in the cytosolic N-terminal region. Substrate recognition involves a direct interaction between TRIM2 and a newly identified zinc-coordination motif in TMEM106B that mediates homodimerization, is required for specific protein-protein interactions, and lysosomal size regulation. We found that in addition to catalysis, the tripartite motif is involved in substrate recruitment. Our study thus contributes a catalog of TRIM2 effectors and identifies a previously unrecognized regulatory region of TMEM106B crucial to its function.

Keywords:  Lysosome; TMEM106B; TRIM2; Ubiquitination; Zinc-binding

DOI:  https://doi.org/10.1038/s44319-025-00667-3
bioRxiv. 2025 Dec 22. pii: 2025.12.19.695617. [Epub ahead of print]

Tuning the open-close equilibrium of Cereblon with small molecules influences protein degradation.

Suzanne O'Connor, Zoe J Rutter, Angus D Cowan, Markus Zeeb, Florian Binder, Yuting Cao, Sohini Chakraborti, Stefan Djukic, Leonhard Geist, Elizabeth Hogg, Giorgia Kidd, Matthias Krumb, Simon Langer, Denis Schmidt, Liam Martin, Elisha H McCrory, Giacomo Padroni, Ilaria Puoti, Luke Simpson, Manon Sturbaut, Lisa Crozier, Vesna Vetma, Qingzhi Zhang, Kirsten McAulay, Theodor Theis, Alessio Ciulli.

Most PROTACs and molecular glue degraders currently approved or in clinical trials recruit Cereblon (CRBN) as the ubiquitin E3 ligase. Upon binding ligands and molecular glues, CRBN undergoes a significant structural rearrangement from an open to closed state, defined by the positioning of the thalidomide-binding domain (TBD) with respect to the Lon domain. However, the exact molecular basis for this ligand-induced conformational change and its implication to neo-substrate degradation remain elusive. During our campaign to discover novel CRBN binders, we found hits exhibiting distinct biophysical behaviour from classical thalidomide-based ligands. By combining orthogonal biophysical methods of differential scanning fluorimetry, isothermal titration calorimetry, and small-angle X-ray scattering, supported by X-ray crystallography and cryo-EM structures of ligand-bound complexes, we classify CRBN binders between those that can induce CRBN closure, and those that cannot. Mutational studies identify key residues in the CRBN ligand binding pocket and N-terminal belt that are essential for the Lon and TBD domains to come together in the closed state. Finally, we show that the probability to yield active degrader molecules is greatly influenced by whether binders can or cannot induce CRBN closure. Together, our study reveals new molecular insights into the structural basis for how CRBN open-closed equilibrium is directly modulated by compound binding and impact target degradability by CRBN, with important implications to the design of PROTACs and molecular glue degraders.

DOI: https://doi.org/10.64898/2025.12.19.695617
bioRxiv. 2025 Dec 30. pii: 2025.12.29.696916. [Epub ahead of print]

Lysine deficiency within a conserved lysine desert is critical for EEL-1/HUWE1 to support ubiquitin proteasome system function.

Katherine S Yanagi, Brenda J Chen, Sheikh Omar Kunjo, Irini Topalidou, Nicolas Lehrbach.

The ubiquitin proteasome system (UPS) is the primary mechanism for targeted protein degradation in eukaryotic cells. Dysfunction of this system is a driver of human disease and a hallmark of aging and late-onset neurodegenerative disorders. Understanding the mechanisms that ensure robust protein turnover may provide new avenues for treatment in these contexts. E3 ubiquitin ligases play critical roles in supplying ubiquitinated substrates to the proteasome, with HUWE1 being an enormous, versatile, and highly conserved member of this family. Here, we show that the C. elegans HUWE1 ortholog, EEL-1, contributes to robust protein turnover during challenges to the proteolytic capacity of the proteasome. We demonstrate that the ability of EEL-1/HUWE1 to safeguard protein turnover requires ubiquitin-binding domains within the substrate-binding arena and the HECT-type ubiquitin ligase activity, supporting a model in which EEL-1 ensures degradation by increasing ubiquitination of pre-ubiquitinated substrates. EEL-1 contains extensive lysine-deficient regions, found at conserved locations in its substrate-binding arena. Through unbiased mutagenesis screening and precise engineering of the EEL-1 protein, we uncover that introducing lysine residues into these regions is detrimental to UPS function. Together, our findings indicate a central and evolutionarily ancient role for EEL-1/HUWE1 in maintaining optimal UPS function and support targeting this E3 for therapeutic manipulation.

DOI: https://doi.org/10.64898/2025.12.29.696916
J Cell Biol. 2026 Apr 06. pii: e202507116. [Epub ahead of print]225(4):

Mitochondrial presequences harbor variable strengths to maintain organellar function.

Youmian Yan, Baigalmaa Erdenepurev, Thiago N Menezes, Ian Collinson, Natalie M Niemi.

Hundreds of mitochondrial proteins rely on N-terminal presequences for organellar targeting and import. While generally described as positively charged amphiphilic helices, presequences lack a consensus motif and thus likely promote protein import into mitochondria with variable efficiencies. Indeed, the concept of presequence strength underlies biological models such as stress sensing, yet a quantitative analysis of what dictates strong versus weak presequences is lacking. Furthermore, the extent to which presequence strength affects mitochondrial function and cellular fitness remains unclear. Here, we capitalize on the MitoLuc protein import assay to define multiple aspects of presequence strength. We find that select presequences, including those that regulate the mitochondrial unfolded protein response (UPRmt), impart differential import efficiencies during mitochondrial uncoupling. Surprisingly, we find that presequences beyond those associated with stress signaling promote highly variable import efficiency in vitro, suggesting presequence strength may influence a broader array of processes than currently appreciated. We exploit this variability to demonstrate that only presequences that promote robust in vitro import can fully rescue defects in respiratory growth in complex IV-deficient yeast, suggesting that presequence strength dictates metabolic potential. Collectively, our findings demonstrate that presequence strength can describe numerous metrics, such as total imported protein, maximal import velocity, or sensitivity to uncoupling, suggesting that the annotation of presequences as weak or strong requires more nuanced characterization than typically performed. Importantly, we find that such variability in presequence strength meaningfully affects cellular fitness beyond stress signaling, suggesting that organisms may broadly exploit presequence strength to fine-tune mitochondrial import and thus organellar homeostasis.

DOI: https://doi.org/10.1083/jcb.202507116
Autophagy. 2026 Jan 04. 1-3

TBK1 orchestrates autophagy and endo-lysosomal pathways in human neurons.

Daniel A Mordes, Julie Smeyers.

  Haploinsufficiency of TBK1 causes familial ALS and frontotemporal dementia (FTD), yet the mechanisms by which TBK1 loss leads to neurodegeneration remain unclear. Using deep proteomics and phospho-proteomics, we demonstrate that TBK1 regulates select macroautophagy/autophagy factors, targeting cargo receptors and autophagy initiation factors, and also sustains the phosphorylation of the late endosomal marker RAB7A in stem cells and stem cell-derived excitatory neurons. We further uncovered novel TBK1-dependent phosphorylation sites in the key autophagy protein SQSTM1/p62. Loss of TBK1 function results in a cell-autonomous neurodegenerative phenotype characterized by impaired neurite outgrowth and lysosomal dysfunction.

Keywords:  TBK1; lysosomes; neurodegeneration; proteomics; selective autophagy

DOI:  https://doi.org/10.1080/15548627.2025.2609924
J Cell Biol. 2026 Mar 02. pii: e202507084. [Epub ahead of print]225(3):

A Rab1 interactome illuminates a dual role in autophagy and membrane trafficking.

Alexander R van Vliet, Alison K Gillingham, Tomos E Morgan, Yohei Ohashi, Tom S Smith, Ferdos Abid Ali, Sean Munro.

The small GTPase Rab1 is found in all eukaryotes and acts in both ER-to-Golgi transport and autophagy. Several Rab1 effectors and regulators have been identified, but the mechanisms by which Rab1 orchestrates these distinct processes remain incompletely understood. We apply MitoID, a proximity biotinylation approach, to expand the interactome of human Rab1A and Rab1B. We identify new interactors among known membrane traffic and autophagy machinery, as well as previously uncharacterized proteins. One striking set of interactors are the cargo receptors for selective autophagy, indicating a broader role for Rab1 in autophagy than previously supposed. Two cargo receptor interactions are validated in vitro, with the Rab1-binding site in optineurin being required for mitophagy in vivo. We also find an interaction between Rab1 and the dynein adaptor FHIP2A that can only be detected in the presence of membranes. This explains the recruitment of dynein to the ER-Golgi intermediate compartment and demonstrates that conventional methods can miss a subset of effectors of small GTPases.

DOI: https://doi.org/10.1083/jcb.202507084
Nat Commun. 2026 Jan 03. 17(1): 155

Mechanistic insights into recruitment and regulation of the RNA helicase UPF1 in replication-dependent histone mRNA decay.

Alexandrina Machado de Amorim, Guangpu Xue, Wenxia He, Theresa Dittmers, Sarah Lewandowski, Cecilia Perez-Borrajero, Juliane Bethmann, Nevena Mateva, Clemens Krage, Vidhyadhar Nandana, Bernhard Loll, Tarek Hilal, Janosch Hennig, Henning Urlaub, William F Marzluff, Sutapa Chakrabarti.

Metazoan histone mRNAs are a unique class of mRNAs that lack the poly(A) tail present in all other eukaryotic transcripts. Instead, they end in a conserved stem-loop (SL) structure, necessitating a decay mechanism that is distinct from deadenylation-initiated degradation. Here, combining structural and functional approaches, we elucidate molecular mechanisms of initiation of histone mRNA decay. At the end of S-phase, the RNA helicase UPF1, the exoribonuclease 3'hExo and stem-loop binding protein SLBP all contribute to histone mRNA degradation, although how they are mechanistically coupled remained unknown. The cryoEM structure of an UPF1:SL RNA complex, presented here, shows that binding of UPF1 partially melts the RNA stem in the absence of ATP, harnessing the free energy derived from RNA-binding to unwind RNA. This melting event primes the SL-RNA for decay by 3'hExo. Using biochemical and cellular analyses, we demonstrate that SLBP directly engages the UPF1 helicase core to attenuate its unwinding activity and prevent premature degradation. Activation of UPF1 at a later stage promotes SL-RNA decay. We provide direct evidence that UPF1, SLBP and 3'hExo form a degradosome-like assembly that functionally couples SL unwinding and degradation, highlighting a dynamic and intricate network of UPF1-centric interactions that orchestrates timely histone mRNA decay.

DOI: https://doi.org/10.1038/s41467-025-67991-z
Autophagy. 2026 Jan 04. 1-18

Measuring lysosome damage and lysophagy in vivo.

Zelai Wu, Hanyu Zhan, Zhiming Huang, Changjing Wang, Boran Li, Yepeng Hu, Zhida Chen, Wei Liu, Weihua Gong, Yongjuan Sang, Qiming Sun.

  Lysosome homeostasis is vital for cellular fitness due to the essential roles of this organelle in various pathways. Given their extensive workload, lysosomes are prone to damage, which can stimulate lysosomal quality control mechanisms such as biogenesis, repair, or autophagic removal - a process termed lysophagy. Despite recent advances highlighting lysophagy as a critical mechanism for lysosome maintenance, the extent of lysosome integrity perturbation and the magnitude of lysophagy in vivo remain largely unexplored. Additionally, the pathophysiological relevance of lysophagy is poorly understood. To address these gaps, it is necessary to develop quantifiable methods for evaluating lysosome damage and lysophagy flux in vivo. To this end, we created two transgenic mouse lines expressing a tandem fluorescent LGALS3/galectin 3 probe (tfGAL3), either constitutively or conditionally under Cre recombinase control, utilizing the property of LGALS3 to recognize damaged lysosomes. This tool enables spatiotemporal visualization of lysosome damage and lysophagy activity at single-cell resolution in vivo. Systemic analysis across various organs, tissues, and primary cultures from these lysophagy reporter mice revealed significant variations in basal lysophagy, both in vivo and in vitro. Additionally, this study identified substantial changes in lysosome integrity and lysophagy flux in different tissues under stress conditions such as starvation, acute kidney injury and diabetic modeling. In conclusion, these complementary lysophagy reporter models are valuable resources for both basic and translational research.Abbreviation: AAV: adeno-associated virus; ATG7: autophagy related 7; CA-tfGAL3: cre-recombinase-activated tandem fluorescent LGALS3; DAPI: 4',6-diamidino-2-phenylindole; DM: diabetes mellitus; ESCRT: endosomal sorting complex required for transport; GFP: green fluorescent protein; HFD: high-fat diet; Igs2/H11/Hipp11: intergenic site 2; IST1: IST1 factor associated with ESCRT-III; KI: knock-in; LAMP1: lysosomal-associated membrane protein 1; LGALS3: lectin, galactoside-binding, soluble, 3; LLOMe: L-leucyl-L-leucine methyl ester hydrobromide; MEFs: mouse embryonic fibroblasts; NaOx: sodium oxalate; PDCD6IP: programmed cell death 6 interacting protein; PTECs: proximal tubular epithelial cells; RFP: red fluorescent protein; STZ: streptozotocin; TAM: tamoxifen; tfGAL3: tandem fluorescent LGALS3; TMEM192: transmembrane protein 192.

Keywords:  In vivo; lysophagy; lysosome; lysosome damage; ratiometric probe

DOI:  https://doi.org/10.1080/15548627.2025.2608974
Cancer Lett. 2026 Jan 06. pii: S0304-3835(26)00009-1. [Epub ahead of print] 218246

Unraveling Stress-Adaptation Pathways in Cancer: Functional Dissection Through CRISPR-Based Genetic Screens.

Fatemeh Mokhles, Mohammad Amin Moosavi, Alvaro Gutierrez-Uzquiza, Guillermo Velasco, Min Li, Marco Cordani.

  Cancer cells face a hostile microenvironment characterized by hypoxia, nutrient deprivation, endoplasmic reticulum (ER) stress, and oxidative imbalance. To cope with these challenges, they activate an interconnected network of adaptive pathways including autophagy, the unfolded protein response, metabolic reprogramming, and the integrated stress response., which promote cell survival, therapy resistance, immune evasion, and metastasis. CRISPR-based functional genomics has emerged as a powerful strategy to systematically dissect these stress-adaptive networks, enabling the identification of key regulators and vulnerabilities across diverse contexts. In this review, we first summarize tumor progression in major stress conditions and then highlight how CRISPR screening strategies ranging from genome-wide loss-of-function studies to single-cell and combinatorial platforms, are unraveling critical stress regulators. We further discuss emerging tools, model systems, and translational perspectives, underscoring how the integration of CRISPR technologies with multi-omics, artificial intelligence, and advanced preclinical models is reshaping our understanding of cancer stress biology and guiding the development of novel therapeutic strategies. Finally, we addressed how these novel dissection technologies influence translational opportunities, specifically in the context of combining stress-pathway modulators with immunotherapy and targeted therapy drugs.

Keywords:  CRISPR functional genomics; metabolic rewiring; oxidative stress; therapy resistance mechanisms; tumor stress adaptation

DOI:  https://doi.org/10.1016/j.canlet.2026.218246
iScience. 2026 Jan 16. 29(1): 114305

LAMP2A regulates endosomal protein composition and membrane identity in exosome biogenesis.

Joao Vasco Ferreira, Luís Carvalho Ferraz, Ana da Rosa Soares, Mostafa Ejtehadifar, Ana Sofia Carvalho, Michael James Hall, Judit Morello, Hans Christian Beck, Jose Silva Ramalho, Rune Matthiesen, Paulo Pereira.

  The endolysosomal system maintains cellular homeostasis through protein degradation and the release of exosomes that mediate intercellular communication. LAMP2A, a transmembrane protein, has been implicated in selective cargo loading into exosomes, or eLLoC. Here, we investigated how LAMP2A influences endosomal protein composition and function using mass spectrometry of endosomal and exosomal fractions from human retinal pigment epithelial cells. Loss of LAMP2A changed Rab GTPase distribution, reduced cortical actin association, and shifted phosphoinositide dynamics, leading to enhanced endosomal acidification and maturation. These changes extended beyond the loss of proteins containing ExoSignals, the canonical targeting motifs, suggesting that LAMP2A contributes broadly to endosomal identity. Experimental validation confirmed that LAMP2A deficiency reprograms endosomal fate toward degradation while influencing exosome composition. These findings highlight a role for LAMP2A in coordinating membrane identity, endosomal maturation, and intercellular communication through exosomes, providing insights into mechanisms that couple endosomal remodeling with cellular signaling and clearance pathways.

Keywords:  Cell biology; Molecular biology

DOI:  https://doi.org/10.1016/j.isci.2025.114305
Nat Chem. 2026 Jan 07.

Monovalent pseudo-natural products supercharge degradation of IDO1 by its native E3 KLHDC3.

Elisabeth Hennes, Belén Lucas, Natalie S Scholes, Xiu-Fen Cheng, Daniel C Scott, Matthias Bischoff, Katharina Reich, Raphael Gasper, María Lucas, Teng Teng Xu, Sofia Rossini, Lisa-Marie Pulvermacher, Lara Dötsch, Hana Imrichova, Alexandra Brause, Siska Führer, Kesava Reddy Naredla, Sonja Sievers, Kamal Kumar, Petra Janning, Ciriana Orabona, Malte Gersch, Peter J Murray, Brenda A Schulman, Georg E Winter, Slava Ziegler, Herbert Waldmann.

Targeted protein degradation modulates protein function beyond the inhibition of enzyme activity or protein-protein interactions. Most degrader drugs function by directly mediating the proximity between a neosubstrate and a hijacked E3 ligase. Here we identify pseudo-natural products derived from (-)-myrtanol, termed iDegs, that inhibit and induce degradation of the immunomodulatory enzyme indoleamine-2,3-dioxygenase 1 (IDO1) by a distinct mechanism. iDegs boost IDO1 ubiquitination and degradation by the cullin-RING E3 ligase CRL2KLHDC3, which we identified to natively mediate ubiquitin-mediated degradation of IDO1. Therefore, iDegs increase IDO1 turnover using the native proteolytic pathway. In contrast to clinically explored IDO1 inhibitors, iDegs reduce the formation of kynurenine by both inhibition and induced degradation of the enzyme and thus also modulate the non-enzymatic functions of IDO1. This unique mechanism of action may open up alternative therapeutic opportunities for the treatment of cancer beyond classical inhibition of IDO1.

DOI: https://doi.org/10.1038/s41557-025-02021-5
Cancer Cell. 2026 Jan 08. pii: S1535-6108(25)00547-1. [Epub ahead of print]

Ubiquitination-directed cytosolic DNA degradation governs cGAS-STING-mediated immune response to DNA damage.

Lei Li, Qi Ye, Jinlu Ma, Zixi Wang, Tianjie Liu, Yuzeshi Lei, Mingming Lu, Jialu Kang, Haohan Xiang, Buyun Li, Shan Xu, Ke Wang, Yule Chen, Jiaqi Chen, Bohan Ma, Wenyue Huang, Mengjiao Cai, Nan Wu, Yanqiang Li, Jiale An, Chongming Jiang, Rui Ye, Jing Liu, Steven H Lin, Yang Gao, Jian Ma, Lei Li.

  Activation of cGAS-STING signaling in cancer cells requires cytosolic DNA produced by intrinsic or treatment-induced DNA damage. However, clinical efforts to exploit this pathway to improve immunotherapy have yielded limited success, highlighting gaps in understanding the link between DNA damage and immunotherapy. Here, we identify ubiquitination-directed cytosolic DNA degradation as a critical determinant for cGAS-STING activation following DNA damage. Mechanistically, the cytosolic DNA exonuclease TREX1 is degraded by the E3 ubiquitin ligase SPOP but is reversely stabilized by the deubiquitinase USP7. Cancer-associated SPOP mutations or USP7 overexpression elevate TREX1 levels, promoting cytosolic DNA degradation and impairing cGAS-STING-mediated immune activation. Notably, elevated USP7 expression correlates with reduced tumor-infiltrating lymphocytes and accelerated disease progression in patients undergoing chemoradiotherapy. Furthermore, USP7 inhibitors reduce TREX1 levels and restore immune responses following radiation. These findings elucidate the mechanisms linking DNA damage to immune activation and highlight USP7 inhibitors as potential enhancers of radioimmunotherapy.

Keywords:  SPOP mutation; TREX1; cytosolic DNA; immune responses; radiotherapy

DOI:  https://doi.org/10.1016/j.ccell.2025.12.013
Res Sq. 2025 Dec 11. pii: rs.3.rs-7292507. [Epub ahead of print]

Coupling the MAPK Slt2/ERK1 Pathway and IRE1-driven UPR Through Transcription Factor Rlm1/MEF2.

Madhusudan Dey, Anish Chakraborty, Saswata Chakrabarty, Jagadeesh Kumar Uppala, Kimberly Ann Mayer, Anna Evans, Jasmine George, Chandrima Ghosh, Ritisha Dey, An Phu Tran An Phu Tran Nguyen, Nadege N Gouignard, Pradeep Chaluvally-Raghavan.

Unfolded protein response (UPR) is a conserved cellular strategy that enhances the protein folding capacity of cells under stress conditions. In Saccharomyces cerevisiae, the dual kinase RNase IRE1 initiates the UPR by catalyzing the cytosolic splicing of HAC1 mRNA, a process conserved in humans where IRE1 splices XBP1 mRNA. The spliced HAC1/XBP1 mRNA yields a transcription factor that upregulates the expression of protein-folding enzymes and chaperones, thereby boosting the cell's ability to cope with unfolded proteins. Our study demonstrates that the UPR involves two distinct phases. The early phase operates predominantly through the canonical IRE1 signaling pathway, while the later phase involves additional regulation by the MAP kinase Slt2 or its human ortholog ERK1/ERK2/ERK5 and the downstream target the MADS-box transcription factor Rlm1 (an ortholog of human MEF2C). We further show that Slt2 promotes IRE1 expression through Rlm1. Together, these findings reveal a previously unrecognized crosstalk between the MAPK and IRE1-mediated arm of the UPR.

DOI: https://doi.org/10.21203/rs.3.rs-7292507/v1
Nat Commun. 2026 Jan 09.

Endothelial IRE1α promotes thrombospondin-1 mRNA decay and supports metabolic stress adaptation of pancreatic islets.

Xiaoge Zhang, Shijia Huang, Peng Chen, Ziyin Zhang, Jie Cai, Ting Yu, Zhixiong Xia, Shubo Yuan, Yong Chen, Mengjuan Gao, Zhuyin Wu, Jiongyi He, Yifei Liao, Qi Fu, Qiong Yang, Tailang Yin, Jie Liu, Ke Song, Sheng-Zhong Duan, Tao Yang, Liangyou Rui, Yi Arial Zeng, Zhuo-Xian Meng, Jianmiao Liu, Yong Liu.

Vascular endothelial cells (ECs) play pivotal roles in maintaining metabolic tissue homeostasis, and EC dysfunction is associated with obesity and metabolic disorders. The mammalian ER stress sensor IRE1α kinase/RNase responds to metabolic cues, but it remains unclear whether endothelial IRE1α is implicated in controlling systemic metabolism. Here we show that genetic depletion of IRE1α in ECs leads to maladaptation of pancreatic islets under obesity-associated metabolic stress. We find that in high-fat diet-fed male mice, loss of IRE1α in ECs has no significant impact upon adiposity, but unexpectedly results in glucose intolerance with impaired insulin secretion, accompanied by blunted intra-islet angiogenesis and compensatory islet growth. Mechanistically, IRE1α RNase decays the mRNA encoding the endogenous anti-angiogenic factor thrombospondin-1 (THBS1/TSP1) in islet ECs. These findings thus uncover a critical role of the endothelial IRE1α suppression of THBS1 in governing the vascular support that enables the functional adaptation of islets to metabolic stress.

DOI: https://doi.org/10.1038/s41467-025-68276-1
bioRxiv. 2026 Jan 02. pii: 2026.01.02.697403. [Epub ahead of print]

A prelimbic molecular clock of protein synthesis for memory persistence.

J Iqbal, S Kim, S Lawal, A Shah, L Punepalle, H Sanghvi, A Gallagher, A Wilson, B Xu, P Shrestha.

Emotionally salient associative memories can endure for long periods, yet the mechanisms that determine their long-term stability remain unclear. Here we show that the prelimbic (PL) cortex integrates temporally structured translational programs to control both the consolidation and reconsolidation of cued threat memories. Using Pavlovian threat conditioning with in vivo fiber photometry, we found that PL calcium dynamics tightly track memory strength: discrete threat-predictive cues evoked robust activity during recent and single-timepoint remote retrieval, whereas prior retrieval selectively weakened remote expression, independent of contextual influences. Translational profiling of PL Camk2a ⁺ cells uncovered a biphasic consolidation program, with an early phase characterized by ER stress-linked translational repression and robust oligodendrocyte plasticity, followed by a delayed phase engaging synaptic growth pathways. Loss- and gain-of-function approaches demonstrated that eIF2α-regulated, cap-independent translation is essential for recent consolidation and for the enduring stabilization of remote memory, whereas retrieval-induced destabilization engages a mechanistically distinct, eIF4E-dependent translational pathway required for reconsolidation. These findings identify the PL cortex as a dynamic node in which discrete modes of translational control govern the long-term persistence of emotional memories.

DOI: https://doi.org/10.64898/2026.01.02.697403
Science. 2026 Jan 08. eadv7953

Computational design of conformation-biasing mutations to alter protein functions.

Peter E Cavanagh, Andrew G Xue, Shizhong A Dai, Albert Qiang, Tsutomu Matsui, Alice Y Ting.

Conformational biasing (CB) is a rapid and streamlined computational method that uses contrastive scoring by inverse folding models to predict protein variants biased toward desired conformational states. We successfully validated CB across seven diverse datasets, identifying variants of K-Ras, SARS-CoV-2 spike, β2 adrenergic receptor, and Src kinase with improved conformation-specific functions, such as enhanced binding or enzymatic activity. Applying CB to the enzyme lipoic acid ligase (LplA), we uncovered a previously unknown mechanism controlling its promiscuous activity. Variants biased toward an "open" conformation state became more promiscuous, whereas "closed"-biased variants were more selective, enhancing LplA's utility for site-specific protein labeling with fluorophores in living cells. The speed and simplicity of CB make it a versatile tool for engineering protein dynamics with broad applications in basic research, biotechnology, and medicine.

DOI: https://doi.org/10.1126/science.adv7953
Cytotechnology. 2026 Feb;78(1): 25

Characteristics of endoplasmic reticulum stress changes during the differentiation of adipose-derived stromal cells into neurons.

Wen Li, Yi Yuan, Pingshu Zhang, Zhenjiang Liu, Qi Wu, Qi Yan, Xiaodong Yuan.

  Adipose-derived stromal cells (ADSC) show promise for neuronal differentiation, but their utility is limited by late-stage cell death, which may be driven by endoplasmic reticulum stress (ERS). To investigate this mechanism, we employed an integrated approach combining immunocytochemistry, western blotting, single-cell RNA sequencing (scRNA-Seq), and transmission electron microscopy (TEM) to systematically profile ERS-related gene expression, dynamic changes of key proteins, and ultrastructural evolution of the ER during neuronal induction. Our results demonstrate that ERS pathways are activated throughout the differentiation process. In early stages, the endoplasmic reticulum (ER) chaperone GRP78 initially increased but markedly declined at 6 h and 8 h. Key UPR sensors IRE1α, XBP1s, PERK, and ATF6 peaked in undifferentiated ADSC and Pre-induction (Prei-1d) cells, then gradually decreased as differentiation progressed. In contrast, pro-apoptotic markers CHOP and Caspase-3 were continuously upregulated in later phases, accompanied by ultrastructural hallmarks of ER dilation, disrupted mitochondrial cristae, and cytoplasmic vacuolization. These findings indicate that ERS initially activates the unfolded protein response to maintain ER homeostasis and support differentiation, whereas sustained ERS at later stages shifts toward CHOP/Caspase-3-dependent apoptosis, leading to cellular injury. This study provides a theoretical basis for optimizing neuronal differentiation protocols through time-dependent modulation of ERS pathways.

Keywords:  Adipose-derived stromal cells; Differentiation of cell; Endoplasmic reticulum stress; Neurons; Unfolded protein response

DOI:  https://doi.org/10.1007/s10616-025-00891-8
bioRxiv. 2025 Dec 29. pii: 2025.12.28.696697. [Epub ahead of print]

SARS-CoV-2 and MERS-CoV disrupt host protein synthesis via nsp1 with differential effects on the integrated stress response.

Nicholas A Parenti, Renee Cusic, David M Renner, Nathaniel Jackson, Chengjin Ye, Li Hui Tan, Jessica J Pfannenstiel, Anthony R Fehr, Noam A Cohen, Luis Martinez-Sobrido, James M Burke, Susan R Weiss.

Coronaviruses pose a serious threat to public health, driving the need for antiviral therapeutics and vaccines. Therefore, it is paramount to understand how this family of viruses evades cellular antiviral responses and establishes productive infection. The conserved coronavirus non-structural protein (nsp)1 has been shown to inhibit host protein synthesis and promote host mRNA degradation while viral mRNAs are protected. We showed previously that SARS-CoV-2 induces activation of host integrated stress response (ISR) kinases PKR and PERK, which promote phosphorylation of eIF2α and consequent inhibition of host protein synthesis. In contrast, eIF2α remains unphosphorylated during MERS-CoV infection. To investigate the interactions of nsp1 and the ISR kinases, we utilized recombinant SARS-CoV-2 and MERS-CoV expressing nsp1 with mutations in each of two conserved domains. Upon infection with SARS-CoV-2 nsp1 mutants, translation was shut down in wildtype (WT) and PKR knockout (KO) cells but rescued in PERK KO cells, likely due to reduced p-eIF2α. In contrast, translation was rescued during infection with the analogous MERS-CoV nsp1 mutants even in WT cells. Moreover, SARS-CoV-2 WT suppressed expression of GADD34, a negative regulator of eIF2α phosphorylation, while SARS-CoV-2 nsp1 mutants induced GADD34. In contrast MERS-CoV WT induced GADD34. Utilizing single-molecule fluorescence in situ hybridization, we found that SARS-CoV-2 and MERS-CoV nsp1 promote host mRNA degradation during WT, but not nsp1 mutant, infection. Finally, while SARS-CoV-2 WT suppressed stress granule formation, nsp1 mutants induced stress granules containing host RNA. Thus, SARS-CoV-2 and MERS-CoV differ in interactions with the ISR and nsp1 control of host protein synthesis.
Significance: Coronaviruses cause disease across a wide range of animal species, and the human coronaviruses SARS-CoV-2 and MERS-CoV have caused epidemics of severe respiratory illness. Thus, it is imperative to understand how these viruses antagonize host responses and cause lethal disease. We show here that the betacoronavirus non-structural protein (nsp)1 promotes shutdown of host protein synthesis while preserving viral protein synthesis and, in addition, promotes degradation of host mRNAs. However, SARS-CoV-2 and MERS-CoV differ in their ability to manipulate the host integrated stress response, indicating that it is important to understand detailed coronavirus-host interactions and how they differ even between lethal coronaviruses. Such insights will inform the development of antiviral therapeutics to treat and prevent current and future coronavirus outbreaks.

DOI: https://doi.org/10.64898/2025.12.28.696697
J Mol Biol. 2026 Jan 07. pii: S0022-2836(26)00009-4. [Epub ahead of print] 169636

A survey of predicted protein-protein interactions involving disordered regions in humans.

Jimin Pei, Jing Zhang, Qian Cong.

  Intrinsically disordered regions (IDRs) in proteins play a pivotal role in protein-protein interactions (PPIs). Using AlphaFold2 and enriched multiple sequence alignments, we predicted and investigated PPIs across the human proteome, focusing on those involving disordered regions. Our predictions show that disordered regions predominantly interact with ordered domains, whereas predicted disordered-disordered interactions are relatively rare. Although disordered regions typically lack annotated domains, certain regions-such as the keratin type II head domain and the Krüppel-associated box (KRAB)-mediate specific interactions. In contrast, their predicted binding partners frequently feature diverse Pfam domains, including protein kinase, WD40 repeat, and nuclear hormone receptor domains. These domains are enriched in nuclear localization and α-helical repeat motifs. Disordered regions involved in predicted PPIs exhibit higher sequence conservation than non-interacting disordered regions, suggesting evolutionary constraints at interaction interfaces. Moreover, certain posttranslational modifications (e.g., phosphorylation and acetylation) in disordered regions are enriched within predicted interaction interfaces, likely modulating binding affinities. Notably, we identified a significant enrichment of disease-associated mutations in predicted PPI interfaces involving disordered regions, underscoring their functional and pathological relevance. Together, these findings highlight the intricate interplay between disordered and ordered regions in mediating PPIs and provide insights into their structural and functional contributions to human health and disease.

Keywords:  AlphaFold2; Disease-associated mutations; Human proteome; Intrinsically disordered regions; Posttranslational modifications; Protein–protein interactions; Sequence conservation

DOI:  https://doi.org/10.1016/j.jmb.2026.169636
Nat Rev Immunol. 2026 Jan 05.

Ubiquitination and autophagy in host-pathogen interactions: from immune surveillance to therapeutic targeting.

João Mello-Vieira, Ivan Dikic.

Ubiquitination, the covalent attachment of ubiquitin to proteins and other cellular substrates, is a dynamic post-translational modification that enables cells to rapidly respond to internal and external threats. Beyond its canonical role in targeting proteins for proteasomal degradation, ubiquitination orchestrates the assembly of signalling complexes that regulate innate and adaptive immune responses, modulates inflammatory pathways and directs selective autophagy to eliminate intracellular pathogens through lysosomal degradation. To persist and replicate within the host, viruses, bacteria and parasites have evolved diverse mechanisms to evade, manipulate or exploit the host's ubiquitin and autophagy machinery. Some pathogens subvert these systems to dampen immune surveillance, whereas others co-opt them to facilitate replication or dissemination. In this Review, we examine how ubiquitin and autophagy shape host-pathogen interactions, uncover common and pathogen-specific strategies of immune evasion, and discuss emerging therapeutic approaches that aim to leverage these interconnected pathways to enhance antimicrobial immunity.

DOI: https://doi.org/10.1038/s41577-025-01239-1
Nat Commun. 2026 Jan 08.

Dynamins maintain nuclear envelope homeostasis and genome stability.

Célia Aveleira, Thibaud Martial, Loïc Carrique, Rita Gaspar, Ana Caulino-Rocha, Izaak Myatt, Franz Wendler, Pauline Lascaux, Misha Le Claire, James Bancroft, Carl Smythe, Kristijan Ramadan, Nuno Raimundo, Ira Milosevic.

The nuclear envelope is a protective barrier for the genome and a mechanotransduction interface between cytoplasm and nucleus, whose malfunction disrupts nucleocytoplasmic transport, compromises DNA repair, accelerates telomere shortening, and promotes genomic instability. Mechanisms governing nuclear envelope remodeling and maintenance in interphase and post-mitotic cells remain poorly understood. Here, we report a role for dynamins, a family of essential brain-enriched membrane- and microtubule-binding GTPases, in preserving nuclear envelope and genomic homeostasis. Cells lacking dynamins exhibit nuclear envelope dysmorphisms, including buds with long narrow necks where damaged DNA frequently accumulates. These cells also show impaired autophagic clearance, reduced levels of key DNA repair proteins, and aberrant microtubules. Nocodazole treatment restores nuclear morphology and reduces DNA damage. Collectively, the data reveal that dynamins promote nuclear envelope homeostasis and removal of damaged DNA via their GTPase activity and interaction with microtubules, providing insights into mechanisms that uphold genome stability and counteract aging-related pathologies.

DOI: https://doi.org/10.1038/s41467-025-68130-4
Commun Biol. 2026 Jan 02.

Reshaping cancer cell plasticity by P-body dynamics and protein translation.

Emanuela Senatore, Laura Rinaldi, Francesco Chiuso, Antonio Giuseppe Bianco, Antonio Feliciello.

Processing bodies (P-bodies) are membrane-less organelles composed of condensed mRNAs and proteins that play essential role in mRNAs decay and storage, contributing to the translational control of cellular proteostasis. Regulation of P-body assembly/disassembly by signaling events, cellular stress or specific environmental conditions shapes the rate of RNA turnover and protein synthesis, controlling cell growth, differentiation and survival. Deregulation of protein translation is an important factor for tumor development and progression and cancer cells benefit from P-bodies to reshape their proteome to support specific metabolic needs and promote tumor development, progression and metastasis. Hence, understanding the composition and the regulation of P-bodies, both under physiological and pathological conditions, will define the mechanisms underlying cancer cell plasticity and develop novel therapeutic strategies to inhibit cancer growth and metastasis. Here, we will discuss the principal mechanisms of P-body regulation and function, with special focus on the role of these ribonucleoprotein condensates in cancer.

DOI: https://doi.org/10.1038/s42003-025-09439-0
Nat Chem Biol. 2026 Jan 07.

Membrane editing with proximity labeling reveals regulators of lipid homeostasis.

Reika Tei, Xiang-Ling Li, Lin Luan, Jeremy M Baskin.

Cellular lipid metabolism is subject to strong homeostatic regulation, but the players involved in and mechanisms underlying these pathways remain largely uncharacterized. Here we develop a 'feeding-fishing' approach coupling membrane editing using optogenetic lipid-modifying enzymes (feeding) with organelle membrane proteomics through proximity labeling (fishing) to elucidate molecular players and pathways involved in the homeostasis of phosphatidic acid (PA), a multifunctional lipid central to glycerolipid metabolism. This approach identified several PA-metabolizing enzymes and lipid transfer proteins enriched in and depleted from PA-fed membranes. Mechanistic analysis revealed that PA homeostasis in the cytosolic leaflets of the plasma membrane and lysosomes is mediated by both local PA metabolism and the action of lipid transfer proteins that carry out interorganelle lipid transport before subsequent metabolism. More broadly, the interfacing of membrane editing to controllably modify membrane lipid composition with organelle membrane proteomics using proximity labeling represents a strategy for revealing mechanisms governing lipid homeostasis.

DOI: https://doi.org/10.1038/s41589-025-02104-x
bioRxiv. 2025 Dec 23. pii: 2025.12.21.695844. [Epub ahead of print]

Eukaryotic initiation factor 3d Regulates Context-Dependent Pain Hypersensitivity Through the Integrated Stress Response.

Subhaan M Mian, Sera I Nakisli, Brodie J Woodall, Pooja J Patel, Aariz Nackvi, Noura Elhamadany, Kree Goss, Nwasinachi Adriana Ezeji, Muhammad Saad Yousuf.

Eukaryotic translation initiation factor 3 subunit D (eIF3d) is a noncanonical cap binding protein implicated in selective mRNA translation under stress conditions. Here, we investigate the contribution of eIF3d to pain processing using a heterozygous eIF3d knockout (eIF3d +/- ) mouse model. We first validated this model, confirming substantial reductions in eIF3d mRNA and protein levels in dorsal root ganglia. Baseline assessments revealed no differences in mechanical, thermal, cold, or spontaneous pain behaviors between eIF3d +/- (HET) and eIF3d +/+ (WT) mice, indicating intact basal nociceptive function. In pain models involving peripheral inflammation and metabolic stress, including methylglyoxal injection, IL-6 administration and paw incision, HET mice displayed significantly reduced mechanical and cold hypersensitivity. In contrast, HET mice exhibited increased second phase nocifensive behavior in the formalin test, possibly indicating enhanced central sensitization. Hyperalgesic priming was comparable between HET and WT mice following IL-6 exposure. Experimental autoimmune encephalomyelitis (EAE) induced mice were unaffected by eIF3d reduction. These findings demonstrate that eIF3d selectively modulates nociceptive plasticity under defined stress conditions and suggests a context dependent role in the regulation of inflammatory and central pain sensitization.
Highlights: Baseline mechanical, thermal, cold and spontaneous pain are intact in eIF3d +/- mice Methylglyoxal-evoked ISR activation and mechanical pain is blunted in eIF3d +/- mice IL-6-evoked mechanical and cold pain are reduced without altered priming Mechanical hypersensitivity is reduced in eIF3d +/- mice with paw incision EAE pain is unaltered but increased pain in phase II formalin pain in eIF3d +/- mice.

DOI: https://doi.org/10.64898/2025.12.21.695844
Cell Chem Biol. 2026 Jan 02. pii: S2451-9456(25)00398-8. [Epub ahead of print]

Identification of aryl hydrocarbon receptor as a functional target that enhances astrocytic ApoE secretion.

Kirk W Donovan, Eric Stefan, Bekim Bajrami, Melissa Bennion, Sarah Huff, Darsheed N Mustafa, Mei-Ju Su, Sofya Dragan, Simone Sciabola, Yi-Ying Chou, Jude Prah, Xiaofeng Li, Douglas S Johnson, Dominic M Walsh, James S Harvey.

  We report the discovery of a chemical series that enhances ApoE secretion from human astrocytes through mechanisms independent of LXR agonism. Target deconvolution of hits from a phenotypic screen in astrocytoma cells employed chemoproteomics, photoaffinity probes, in vitro KINOMEscan analysis, and targeted siRNA knockdown experiments. Photoaffinity labeling coupled with quantitative chemical proteomics identified aryl hydrocarbon receptor (AhR), a transcription factor not previously associated with ApoE secretion, as the primary target. A diverse panel of AhR agonists and antagonists together with genetic knockdown confirmed that ApoE secretion increases when AhR activity is reduced. Using a luciferase reporter assay, we demonstrated that active series analogs exhibit AhR antagonism while inactive compounds do not. Since deletion of AhR has severe peripheral effects, chronic inhibition of AhR is not an attractive therapeutic approach for Alzheimer's disease; nevertheless, these results position AhR as a modulator of ApoE secretion and a biological pathway worth exploring.

Keywords:  Alzheimer’s disease; ApoE secretion; aryl hydrocarbon receptor; chemoproteomics and mechanistic studies; phenotypic screen

DOI:  https://doi.org/10.1016/j.chembiol.2025.12.005
iScience. 2026 Jan 16. 29(1): 114264

A mechanism for the disrupted redox regulation of vascular contractility during aging.

Leonardo Y Tanaka, Lucas F Gutierre, Ricardo C Massucatto, Geovana S Garcia, Carolina M Portas, Victor Debbas, Júlia M F de Souza, Tiphany C De Bessa, Lívia Teixeira, Percíllia V S Oliveira, Beatriz P Souza, Samantha K Teixeira, Paola C Branco, Ayumi A Miyakawa, Renato S Gaspar, Daniela Kajihara, Iuri C Valadão, Amit Bhowmik, Kate Carroll, Francisco R M Laurindo.

  Vascular dysfunction contributes to aging-related phenotype, but mechanisms remain unclear. We propose that aging promotes a deregulated convergence between cellular redox processes and mechanoregulation. We focus on Protein Disulfide Isomerase-A1 (PDI), an endoplasmic reticulum redox chaperone known to modulate NADPH oxidase complexes and to fine-tune cytoskeletal remodeling. Our hypothesis is that PDI connects oxidant generation to actin cytoskeleton remodeling via the modulation of protein sulfenylation, an oxidative post-translational modification. We first show that protein sulfenylation supports vascular contractility and F-actin assembly during mechanoadaptation or agonist-induced contraction. Meanwhile, PDI supports sulfenylation-dependent actin remodeling. Moreover, aged murine arteries lose the sulfenic acid-related component of contractility, while PDI overexpression over-rides this dysfunction and restores aging-related vascular contractility. We further confirm a direct PDI-actin interaction modulated by sulfenic acid. Overall, signaling connections between PDI and sulfenylated proteins behave as an upstream integrative system regulating F-actin assembly, a mechanism that is impaired during aging-induced vascular dysfunction.

Keywords:  Age; Biochemistry; Cell biology; Vascular anatomy

DOI:  https://doi.org/10.1016/j.isci.2025.114264