bims-micesi 2025-11-30 papers

bims-micesi

Biomed News

on Mitotic cell signalling

Issue of 2025–11–30
thirteen papers selected by
Valentina Piano, Uniklinik Köln

Suppression of the lipid-transport activity of OSBPL11 weakens the cytotoxicity of SAC-activating drugs by promoting mitotic slippage.
The CENP-A chaperone complex spatially organizes centromeres.
Mitotic dynamics of the nuclear lamina in the backstage of chromosome separation.
PTEN-deficient, chromosomal instability colorectal cancer is hypersensitive to STAT3 inhibition.
The scaffold protein PRR14L links the PP2A-TACC3 axis to mitotic fidelity and sensitivity to MPS1 inhibition.
A chromatin-associated pool of Aurora A controls kinetochore-microtubule attachments to ensure chromosome biorientation.
Cell size reduction scales spindle elongation but not chromosome segregation in C. elegans.
Resolving interface structure and local internal mechanics of mitotic chromosomes.
Where, When, and How? Integrating Spatiotemporal Cues in Cell Division.
Phosphatase specificity influences phosphorylation timing of CDK substrates during the cell cycle.
Mitotic bypass and endocycling promote cancer cell survival after genotoxic chemotherapy.
Progressive coevolution of the yeast centromere and kinetochore.
Localized Wnt-signaling promotes asymmetric NuMA-dependent oriented divisions and unequal apportioning of mitochondria.

Biochem Biophys Res Commun. 2025 Nov 26. pii: S0006-291X(25)01761-9. [Epub ahead of print]794 153045

Suppression of the lipid-transport activity of OSBPL11 weakens the cytotoxicity of SAC-activating drugs by promoting mitotic slippage.

Ayaka Kawaji, Ryuzaburo Yuki, Youhei Saito, Yuji Nakayama.

  Sustained activation of the spindle assembly checkpoint (SAC) arrests cells in mitosis, resulting in mitotic cell death; therefore, SAC-activating drugs have been developed and clinically used as anti-cancer agents. However, some mitotic cells exhibit mitotic slippage, an event of mitotic exit without SAC satisfaction, and less sensitivity to these drugs. For developing efficient anti-cancer therapy, it is required to reveal the mechanism underlying the cell fate determination between cell death and mitotic slippage. In this study, we found that oxysterol-binding protein-like 11 (OSBPL11) is important for cell fate determination during mitotic arrest. OSBPL11 knockdown accelerates mitotic slippage and instead represses cell death during mitotic arrest by treatment with the Eg5 inhibitor S-trityl-l-cysteine (STLC), although the duration from mitotic entry to slippage or death is not altered. OSBPL11 knockdown exhibits a similar phenotype in paclitaxel-treated cells. Cyclin B1 levels are decreased in OSBPL11-knockdown mitotic cells. Treatment with the APC/C inhibitor proTAME mitigates both the decrease in the cyclin B1 levels and the acceleration of mitotic slippage caused by OSBPL11 knockdown. Although the OSBPL11 wild type could mitigate the acceleration of mitotic slippage and the repression of cell death induced by OSBPL11 knockdown, mutants lacking the lipid transport and lipid binding activities could not. Furthermore, OSBPL11 knockdown promotes survival upon STLC and paclitaxel treatments. These results suggest that OSBPL11 represses mitotic slippage and accelerates cell death during mitotic arrest in a manner dependent on both lipid transport and lipid binding activities, promoting the cytotoxic effect of SAC-activating drugs.

Keywords:  Cell death; Lipid transport; Mitosis; Mitotic slippage; Oxysterol-binding protein-like 11; Spindle assembly checkpoint

DOI:  https://doi.org/10.1016/j.bbrc.2025.153045
bioRxiv. 2025 Nov 09. pii: 2025.11.07.687291. [Epub ahead of print]

The CENP-A chaperone complex spatially organizes centromeres.

Hindol Gupta, Julian Haase, Yicong Wu, Jiji Chen, George Karadimov, Hari Shroff, Alexander E Kelly.

Centromeres, defined by CENP-A-containing nucleosomes, direct the assembly of kinetochores for spindle attachment. In mitosis, CENP-A and the constitutive centromere-associated network (CCAN) of the inner kinetochore are arranged into bipartite subdomains within clearings of chromatin. However, it remains unclear whether any of these features exist before mitosis. We show that in interphase, CENP-A and the CCAN assemble ∼200-300 nm shell-like structures that enclose a chromatin-poor central cavity. Strikingly, this cavity is occupied by the interphase-specific CENP-A chaperone complex, which promotes CENP-A assembly once per cell cycle. However, chaperone presence, but not CENP-A incorporation, is required to generate both the shell architecture and the chromatin clearing. The CCAN scaffold CENP-C, which links CENP-A nucleosomes to the chaperone complex, exhibits radial organization spanning the entire structure and is essential for its formation. These data uncover a previously unrecognized structural role for the CENP-A chaperone machinery in establishing interphase centromere architecture and suggest a mechanism by which this machinery configures centromeres for faithful kinetochore assembly and genome stability.

DOI: https://doi.org/10.1101/2025.11.07.687291
Commun Biol. 2025 Nov 26. 8(1): 1687

Mitotic dynamics of the nuclear lamina in the backstage of chromosome separation.

Julien Picotto, Pascale Bertrand, Gaëlle Pennarun.

The regulation of mitosis is essential for genome inheritance and stability. In mammals, many cellular ultrastructures, including the nuclear envelope, undergo significant morphological changes to facilitate chromosome separation. In particular, the lamina, a key nuclear envelope subcompartment, experiences drastic structural changes throughout mitosis, from its rapid and complete dissociation during the nuclear envelope breakdown to its reassembly during mitotic exit. Interestingly, intermediate states of assembly of both A and B-type lamins, the major components of the lamina, have been reported to support mitotic progression and spindle formation. Here we review the various contributions of lamins to mitosis, beyond nuclear envelope breakdown and reassembly. In addition, we discuss how lamin defects in pathological contexts affect mitosis and thus genome stability.

DOI: https://doi.org/10.1038/s42003-025-09081-w
Int J Biol Sci. 2025 ;21(15): 6633-6648

PTEN-deficient, chromosomal instability colorectal cancer is hypersensitive to STAT3 inhibition.

Guowen Ren, Yue Pu, Xiumei Zhang, Jinghong Chen, Eun Ju Yang, Shishi Tao, Li-Jie Chen, Wenli Zhu, Kin Long Chan, Guanghui Luo, Chuxia Deng, Joong Sup Shim.

  Genetic alterations that induce chromosomal instability (CIN) in colorectal cancer (CRC) cells result in partial impairments in a crucial cellular process, which present an opportunity for therapeutic exploitation in cancer treatment. In our effort to identify therapeutic vulnerability in PTEN-deficient CRC, we found that PTEN-deficient CRC cells exhibited elevated CIN phenotype and were hypersensitive to STAT3 inhibition. STAT3 inhibition induced a high level of abnormal spindle formation, causing mitotic arrest and death in PTEN-deficient CRC cells. Mechanistically, PTEN deficiency led to an increased phosphorylation in STAT3 and the hyperactivation of the downstream mitotic kinase PLK1, resulting in the formation of abnormal mitotic spindles and CIN. Inhibition of STAT3 strongly suppressed PLK1 phosphorylation in a STMN1-dependent manner, further inducing mitotic abnormalities in the cells. This irreparable mitotic defect triggered hyperactivation of the spindle assembly checkpoint and mitotic cell death in PTEN-deficient CRC cells. Collectively, our findings suggest that targeting STAT3-PLK1 axis represents a novel therapeutic approach for CRC cells with PTEN loss.

Keywords:  Colorectal cancer; PLK1; PTEN; STAT3; Synthetic lethality; chromosomal instability

DOI:  https://doi.org/10.7150/ijbs.111254
bioRxiv. 2025 Nov 06. pii: 2025.11.04.686150. [Epub ahead of print]

The scaffold protein PRR14L links the PP2A-TACC3 axis to mitotic fidelity and sensitivity to MPS1 inhibition.

Albert Z Liu, Akshay Narkar, Keming Li, Thierry Bertomeu, Blake A Johnson, Jasmin Coulombe-Huntington, Yi Dong, Jin Zhu, Mike Tyers, Rong Li.

Aneuploidy is a hallmark of cancer and is a potential vulnerability that can be selectively targeted. To systematically identify genes that affect the incidence and fitness of aneuploid cells, we conducted a genome-wide CRISPR/Cas9 screen using NMS-P715, an inhibitor of the spindle assembly checkpoint (SAC) kinase Mps1/TTK. In this study, we identified a number of genes known to regulate aneuploidy and mitosis, and subsequently focused on PRR14L , a ubiquitously expressed gene previously implicated in chronic myelomonocytic leukemia (CMML). Proximity labeling of PRR14L using TurboID revealed several cell division proteins, including the PP2A-B56 phosphatase complex and the spindle assembly factor TACC3, as PRR14L-interacting proteins. Loss of PRR14L prolongs SAC-dependent mitotic arrest in response to microtubule depolymerization but, paradoxically, leads to catastrophic mitotic errors upon SAC abrogation by MPS1 inhibitors. A model derived from our findings provides a rationale for exploiting MPS1 inhibition as a potential vulnerability in cancers containing either PRR14L loss of function mutations or FGFR-TACC3 fusions.

DOI: https://doi.org/10.1101/2025.11.04.686150
bioRxiv. 2025 Nov 01. pii: 2025.10.31.685952. [Epub ahead of print]

A chromatin-associated pool of Aurora A controls kinetochore-microtubule attachments to ensure chromosome biorientation.

Johnathan L Meaders, Alyssa A Rodriguez, Smriti Variyar, SungWoo Park, Alessandro E Cirulli, Karen Oegema, Kevin D Corbett, Arshad Desai.

Accurate chromosome segregation requires dynamic kinetochore-microtubule attachments that, under the regulation of Aurora family kinases, biorient and align replicated chromosomes. In C. elegans , Aurora A acts with the TPX2-related activator TPXL-1 to regulate these attachments and control spindle length. We show that, in addition to prominent spindle pole localization, TPXL-1-AurA has a chromatin-associated pool positioned between the sister kinetochores. Structural modeling and biochemical analysis support TPXL-1 directly recognizing the nucleosome acidic patch via an arginine anchor. Disrupting this interaction selectively removed chromatin-bound TPXL-1-AurA and caused chromosome missegregation, whereas elevation of the chromatin pool disrupted chromosome alignment. These opposing perturbations inversely affected kinetochore recruitment of the microtubule-binding Ska complex. These results support spatially distinct TPXL-1-AurA populations acting sequentially, with the spindle pole pool controlling spindle length by switching kinetochores out of a depolymerization-coupled state, and the chromatin pool controlling attachment stabilization to ensure biorientation prior to anaphase.

DOI: https://doi.org/10.1101/2025.10.31.685952
bioRxiv. 2025 Oct 14. pii: 2025.10.13.681585. [Epub ahead of print]

Cell size reduction scales spindle elongation but not chromosome segregation in C. elegans.

Chukwuebuka William Okafornta, Reza Farhadifar, Gunar Fabig, Hai-Yin Wu, Maria Köckert, Martin Vogel, Daniel Baum, Robert Haase, Michael J Shelley, Daniel J Needleman, Thomas Müller-Reichert.

How embryos adapt their internal cellular machinery to reductions in cell size during development remains a fundamental question in cell biology 1-11 . Here, we use high-resolution lattice light-sheet fluorescence microscopy and automated image analysis to quantify lineage-resolved mitotic spindle and chromosome segregation dynamics from the 2-to 64-cell stages in Caenorhabditis elegans embryos. While spindle length scales with cell size across both wild-type and size-perturbed embryos, chromosome segregation dynamics remain largely invariant, suggesting that distinct mechanisms govern these mitotic processes. Combining femtosecond laser ablation 12,13 with large-scale electron tomography 14 , we find that central spindle microtubules mediate chromosome segregation dynamics and remain uncoupled from cell size across all stages of early development. In contrast, spindle elongation is driven by cortically anchored motor proteins and astral microtubules, rendering it sensitive to cell size 12,13,15-17 . Incorporating these experimental results into an extended stoichiometric model for both the spindle and chromosomes, we find that allowing only cell size and microtubule catastrophe rates to vary reproduces elongation dynamics across development. The same model also accounts for centrosome separation and pronuclear positioning in the one-cell C. elegans embryo 18 , spindle-length scaling across nematode species spanning ~100 million years of divergence 17 , and spindle rotation in human cells 19 . Thus, a unified stoichiometric framework provides a predictive, mechanistic account of spindle and nuclear dynamics across scales and species.

DOI: https://doi.org/10.1101/2025.10.13.681585
Nat Commun. 2025 Nov 28. 16(1): 10776

Resolving interface structure and local internal mechanics of mitotic chromosomes.

Andrea Ridolfi, Hannes Witt, Janni Harju, Tinka V M Clement, Erwin E J G Peterman, Chase P Broedersz, Gijs J L Wuite.

The interface of chromosomes enables them to interact with the cell environment and is crucial for their mechanical stability during mitosis. Here, we use Atomic Force Microscopy (AFM) to probe the interface and local micromechanics of the highly condensed and complex chromatin network of native human mitotic chromosomes. Our AFM images provide detailed snapshots of chromatin loops and Sister-Chromatids Intertwines. A scaling analysis of these images reveals that the chromatin surface has fractal nature. AFM-based Force Spectroscopy and microrheology further show that chromosomes can resist severe deformations, elastically recovering their initial shape following two characteristic timescales. Localized indentations over the chromatids reveal that the spatially varying micromechanics of the chromatin network is largely governed by chromatin density. Together, our AFM investigation provides insights into the structure and local mechanics of mitotic chromosomes, offering a toolbox for further characterization of complex biological structures, such as chromosomes, down to the nanoscale.

DOI: https://doi.org/10.1038/s41467-025-65821-w
Bioessays. 2025 Nov 27. e70093

Where, When, and How? Integrating Spatiotemporal Cues in Cell Division.

Luca Cirillo, Hradini Konthalapalli, Claudio Alfieri, Jonathon Pines.

To an external observer, the goal of cell division is evident from the very shape of the duplicated chromosomes. Cells, however, cannot see-they must proceed by groping in the dark, searching for their own DNA-and a series of sophisticated spatial mechanisms enables them to align and segregate their genetic material. Spatial organization is only part of the challenge: cell division is also a race against time-spending too little or too much time in mitosis can be equally detrimental to cell survival. Dividing cells must not only coordinate the movement of often dozens of chromosomes but must do so with precise timing. Yet, chromosome segregation occurs with remarkable accuracy. In this review, we highlight the role of mitotic chromosomes as a platform to integrate spatial and temporal cues to ensure their successful segregation.

DOI: https://doi.org/10.1002/bies.70093
Nat Commun. 2025 Nov 24.

Phosphatase specificity influences phosphorylation timing of CDK substrates during the cell cycle.

Theresa U Zeisner, Tania Auchynnikava, Emma L Roberts, Paul Nurse.

Cell cycle events are ordered by cyclin-dependent kinases (CDKs), which phosphorylate hundreds of substrates. Multiple phosphatases oppose these CDK substrates, yet their collective role in regulating phosphorylation timing in vivo remains unclear. Here, we show that four phosphatases (PP2A-B55, PP2A-B56, CDC14, and PP1) each target distinct subsets of CDK substrate sites in vivo in fission yeast, influencing when phosphorylation occurs during G2 and mitosis. On average, sites dephosphorylated by CDC14 and PP2A-B56 are phosphorylated earlier during G2, followed by sites dephosphorylated by PP1 and PP2A-B55. This suggests that these phosphatases set different phosphorylation thresholds at the G2/M transition. Consistent with this, depleting PP2A-B55 or CDC14 accelerates mitotic onset, likely by advancing phosphorylation of their respective CDK substrates, suggesting these phosphorylation thresholds are important for regulating mitotic onset. Our findings establish in vivo phosphatase substrate specificity as a key factor regulating the timing of CDK substrate phosphorylation throughout the cell cycle.

DOI: https://doi.org/10.1038/s41467-025-66547-5
bioRxiv. 2025 Nov 04. pii: 2025.11.03.686258. [Epub ahead of print]

Mitotic bypass and endocycling promote cancer cell survival after genotoxic chemotherapy.

Kevin Truskowski, Louis Rolle, George Butler, Margaret E Yang, Kenneth J Pienta, Sarah R Amend.

Genotoxic chemotherapies are central components of the treatment regimen for most cancers but are rarely curative. Drug-tolerant persister cells (DTPs) evade cell death during these treatments by accessing transient adaptive states, allowing them to contribute to cancer progression after treatment. Here, we demonstrate that cancer cells can survive genotoxic chemotherapy-induced stress by accessing a previously undescribed DTP state where mitotic bypass and continued endocycling promote survival by allowing cells to evade mitotic catastrophe and cell death. Mechanistic studies indicate that mitotic bypass is dependent on CDK1 inhibition by WEE1 and Myt1, which prevents entry into mitosis and induces premature APC/C activation during G2 arrest. Disrupting WEE1 or Myt1 activity using clinical-stage small molecule inhibitors promotes CDK1 reactivation, forcing mitotic entry, catastrophe, and cell death. Our results identify mitotic bypass and endocycling as a targetable mediator of cancer cell persistence that can be exploited for the eradication of DTPs.

DOI: https://doi.org/10.1101/2025.11.03.686258
Nature. 2025 Nov 26.

Progressive coevolution of the yeast centromere and kinetochore.

Jana Helsen, Kausthubh Ramachandran, Gavin Sherlock, Gautam Dey.

During mitosis, stable but dynamic interactions between centromere DNA and the kinetochore complex enable accurate and efficient chromosome segregation. Even though many proteins of the kinetochore are highly conserved1,2, centromeres are among the fastest evolving regions in a genome3,4, showing extensive variation even on short evolutionary timescales. Here we sought to understand how organisms evolve completely new sets of centromeres that still effectively engage with the kinetochore machinery by identifying and tracking thousands of centromeres across two major fungal clades, including more than 2,500 natural strain isolates and representing over 1,000 million years of evolution. We show that new centromeres spread progressively via drift and subsequent selection and that the kinetochore, which is evolving slowly in relative terms, appears to act as a filter to determine which new centromere variants are tolerated. Together, our findings provide insight into the evolutionary constraints and trajectories shaping centromere evolution.

DOI: https://doi.org/10.1038/s41586-025-09779-1
Nat Commun. 2025 Nov 27. 16(1): 10690

Localized Wnt-signaling promotes asymmetric NuMA-dependent oriented divisions and unequal apportioning of mitochondria.

Susanna Eli, Greta Rauso, Paola Ghezzi, James L A Szczerkowski, Michela Bruzzi, Francesca Rizzelli, Fabiola Iommazzo, Alessia Loffreda, Francesco Castagna, Federico Donà, Chiara Gaddoni, Ambra Dondi, Mattia Marenda, Simona Rodighiero, Pierre Tournier, Zeno Lavagnino, Dario Parazzoli, Nils C Gauthier, Simone Tamburri, Diego Pasini, Shukry James Habib, Marina Mapelli.

In multicellular organisms, the execution of developmental and homeostatic programs often relies on asymmetric cell divisions. These divisions require the alignment of the mitotic spindle axis to cortical polarity cues, and the unequal partitioning of cellular components between progeny cells. Asymmetric divisions are orchestrated by signals from the niche frequently presented in a directional manner, such as Wnt signals. Here we employ bioengineered Wnt-niches to demonstrate that in metaphase NuMA/dynein microtubule motors form a complex with activated LRP6 and β-catenin at the cortical sites of Wnt activation to orient cell division perpendicularly. We show that engagement of LRP6 co-receptors by Wnt ligands locally stabilizes actomyosin contractility through the accumulation of myosin1C. Additionally, we describe a proteomic-based approach to identify mitotic protein complexes enriched at the Wnt-contact site, revealing that mitochondria polarize toward localized Wnt3a sources and are asymmetrically apportioned to the Wnt-proximal daughter cell during Wnt-mediated asymmetric cell division of embryonic stem cells. Mechanistically, we show that CENP-F is required for mitochondria polarization towards localized sites of Wnt3a activation, and that deletion of the Wnt-co-receptor LRP6 impairs the asymmetric apportioning of mitochondria. Our findings enhance the understanding of mitotic Wnt-signaling and elucidate fundamental principles underlying Wnt-dependent mitochondrial polarization.

DOI: https://doi.org/10.1038/s41467-025-65775-z