bims-micesi Biomed News
on Mitotic cell signalling
Issue of 2025–03–23
thirteen papers selected by
Valentina Piano, Uniklinik Köln
  1. Interactions with multiple inner kinetochore proteins determine mitotic localization of FACT.
  2. Nuclear exclusion of condensin I in prophase coordinates mitotic chromosome reorganization to ensure complete sister chromatid resolution.
  3. Structural characterization and inhibition of the interaction between ch-TOG and TACC3.
  4. Crosstalk Between Plk1 and PTEN in Mitosis Affects Chromosomal Stability.
  5. lncreased risk of slippage upon disengagement of the mitotic checkpoint.
  6. Molecular design principles for bipolar spindle organization by two opposing motors.
  7. Energy landscape analysis of the development of the chromosome structure across the cell cycle.
  8. The kinesin motor POS3 and the microtubule polymerase MOR1 coordinate chromosome congression during mitosis in Arabidopsis.
  9. Co-inhibition of Aurora kinase B and SUV4-20H induces synthetic lethality in Wild-type p53 deficient cancer cells.
  10. TPX2 lactylation is required for the cell cycle regulation and hepatocellular carcinoma progression.
  11. REV7 functions with REV3 as a checkpoint protein delaying mitotic entry until DNA replication is completed.
  12. High resolution profiling of cell cycle-dependent protein and phosphorylation abundance changes in non-transformed cells.
  13. PLK1 inhibition induces synthetic lethality in Fanconi anemia pathway-deficient acute myeloid leukemia.
  1. J Cell Biol. 2025 May 05. pii: e202412042. [Epub ahead of print]224(5):
    Interactions with multiple inner kinetochore proteins determine mitotic localization of FACT.
    Julia Schweighofer, Bhagyashree Mulay, Ingrid Hoffmann, Doro Vogt, Marion E Pesenti, Andrea Musacchio.
      The FAcilitates Chromatin Transcription (FACT) complex is a dimeric histone chaperone that operates on chromatin during transcription and replication. FACT also interacts with a specialized centromeric nucleosome containing the histone H3 variant centromere protein A (CENP-A) and with CENP-TW, two subunits of the constitutive centromere-associated network (CCAN), a 16-protein complex associated with CENP-A. The significance of these interactions remains elusive. Here, we show that FACT has multiple additional binding sites on CCAN. The interaction with CCAN is strongly stimulated by casein kinase II phosphorylation of FACT. Mitotic localization of FACT to kinetochores is strictly dependent on specific CCAN subcomplexes. Conversely, CENP-TW requires FACT for stable localization. Unexpectedly, we also find that DNA readily displaces FACT from CCAN, supporting the speculation that FACT becomes recruited through a pool of CCAN that is not stably integrated into chromatin. Collectively, our results point to a potential role of FACT in chaperoning CCAN during transcription or in the stabilization of CCAN at the centromere during the cell cycle.
    DOI:  https://doi.org/10.1083/jcb.202412042
  2. Curr Biol. 2025 Mar 13. pii: S0960-9822(25)00211-8. [Epub ahead of print]
    Nuclear exclusion of condensin I in prophase coordinates mitotic chromosome reorganization to ensure complete sister chromatid resolution.
    John K Eykelenboom, Marek Gierliński, Zuojun Yue, Tomoyuki U Tanaka.
      During early mitosis, chromosomes transition from their unfolded interphase state to the distinct rod-shaped structures characteristic of mitosis. This process allows correct segregation of replicated sister chromatids to the opposite spindle poles during anaphase. Two protein complexes, named condensin I and condensin II, facilitate mitotic chromosome organization. Condensin II is important for achieving sister chromatid separation (resolution), while condensin I is required for chromosome condensation (folding). Although sister chromatid resolution occurs earlier than chromosome folding, it is not yet clear how these events are coordinated through time or whether this is important for correct chromosome segregation. In this study, we tested the hypothesis that temporal control is achieved through differential localization of the two condensin complexes; i.e., while condensin II localizes in the nucleus, condensin I is excluded from the nucleus in interphase and prophase. We engineered the localization of condensin I to the nucleus and monitored sister chromatid resolution and chromosome folding by real-time imaging. We found that localization of condensin I to the nucleus led to precocious chromosome folding during prophase, with similar timing to sister chromatid resolution. Furthermore, this change led to incomplete sister chromatid resolution in prometaphase/metaphase and frequent chromosome missegregation in anaphase, in which most missegregated chromosomes consisted of lagging chromosomes involving both sister chromatids. We conclude that, in a physiological context, the exclusion of condensin I from the nucleus during prophase delays chromosome folding and allows condensin II to complete sister chromatid resolution, which ensures correct chromosome segregation later in mitosis.
    Keywords:  chromosome folding (condensation); chromosome segregation; condensin I; condensin II; mitotic chromosome reorganization; sister chromatid resolution
    DOI:  https://doi.org/10.1016/j.cub.2025.02.047
  3. J Cell Biol. 2025 Jun 02. pii: e202407002. [Epub ahead of print]224(6):
    Structural characterization and inhibition of the interaction between ch-TOG and TACC3.
    James Shelford, Selena G Burgess, Elena Rostkova, Mark W Richards, Gabrielle Larocque, Josephina Sampson, Christian Tiede, Alistair J Fielding, Tina Daviter, Darren C Tomlinson, Antonio N Calabrese, Mark Pfuhl, Richard Bayliss, Stephen J Royle.
      The mitotic spindle is a bipolar array of microtubules, radiating from the poles which each contain a centrosome, embedded in pericentriolar material. Two proteins, ch-TOG and TACC3, have multiple functions at the mitotic spindle due to operating either alone, together, or in complex with other proteins. To distinguish these activities, we need new molecular tools to dissect their function. Here, we present the structure of the α-helical bundle domain of ch-TOG that mediates its interaction with TACC3 and a structural model describing the interaction, supported by biophysical and biochemical data. We have isolated Affimer tools to precisely target the ch-TOG-binding site on TACC3 in live cells, which displace ch-TOG without affecting the spindle localization of other protein complex components. Inhibition of the TACC3-ch-TOG interaction led unexpectedly to fragmentation of the pericentriolar material in metaphase cells and delayed mitotic progression, uncovering a novel role of TACC3-ch-TOG in maintaining pericentriolar material integrity during mitosis to ensure timely cell division.
    DOI:  https://doi.org/10.1083/jcb.202407002
  4. DNA Cell Biol. 2025 Mar 21.
    Crosstalk Between Plk1 and PTEN in Mitosis Affects Chromosomal Stability.
    Wei Li, Xianning Wang, Jiannan Liu, Bing Liu, Yongjian Hao.
      The mitotic phase involves the distribution and regulation of genetic material. Defects in gene regulation can lead to serious errors in genetic transmission, such as increased instability of chromosomes, thereby increasing susceptibility to cancer and promoting its development. The maintenance of chromosome stability depends on several mechanisms, such as efficient DNA repair, proper sister chromatid separation, and timely cytokinesis. The serine/threonine kinase Plk1 is a key molecule in maintaining chromosome stability, participating in multiple stages of precise regulation during mitosis, including promoting entry into mitosis, facilitating centrosome maturation and bipolar spindle formation, promoting sister chromatid separation, and facilitating cytokinesis. Several proteins can regulate the kinase activity of Plk1 through protein-protein interactions, coordinating the genetic stability of the cell, including the kinases Aurora A, c-Abl, and Chk1 as well as the phosphatase phosphatase and tension homolog (PTEN). PTEN has been described as an essential regulator of Plk1 for dephosphorylation and chromosomal stability during cell division, and Plk1 may directly interact with and phosphorylate PTEN at centromeres. Here, we review the bidirectional interplay between Plk1 and PTEN and how it contributes to genomic stability during mitosis.
    Keywords:  Centrosome; PTEN; Plk1; chromosome stability; mitosis
    DOI:  https://doi.org/10.1089/dna.2024.0246
  5. PLoS Comput Biol. 2025 Mar 19. 21(3): e1012879
    lncreased risk of slippage upon disengagement of the mitotic checkpoint.
    Alma Beatrix Stier, Paolo Bonaiuti, János Juhász, Fridolin Gross, Andrea Ciliberto.
      Drugs that impair microtubule dynamics alter microtubule-kinetochore attachment and invoke the mitotic checkpoint which arrests cells in mitosis. The arrest can last for hours, but it is leaky: cells adapt (i.e., slip out of it) and exit from mitosis. Here, we investigate the mechanism that allows cells to escape, and whether it is possible to prevent it. Based on a model of the mitotic checkpoint which includes the presence of a positive feedback loop, the escape from the arrest is described as a stochastic transition driven by fluctuations of molecular components from a checkpoint ON to a checkpoint OFF state. According to the model, drug removal further facilitates adaptation, a prediction we confirmed in budding yeast. The model suggests two ways to avoid adaptation: inhibition of APC/C and strengthening the mitotic checkpoint. We confirmed experimentally that both alterations decrease the chance of cells slipping out of mitosis, during a prolonged arrest and after washing out the drug. Our results may be relevant for increasing the efficiency of microtubule depolymerizing drugs.
    DOI:  https://doi.org/10.1371/journal.pcbi.1012879
  6. Proc Natl Acad Sci U S A. 2025 Mar 25. 122(12): e2422190122
    Molecular design principles for bipolar spindle organization by two opposing motors.
    Wei-Xiang Chew, François Nédélec, Thomas Surrey.
      During cell division in animal cells, a bipolar spindle assembles to segregate the chromosomes. Various motor proteins with different properties are essential for spindle self-organization. The minimal set of components required to organize dynamic microtubules into a bipolar network remains however unknown. Here, we use computer simulations to explore whether two types of microtubule-crosslinking motors with opposite directionality can organize dynamic microtubules into bipolar spindles in three-dimensional space around a local microtubule nucleation source. We find that two motors are indeed sufficient, provided their properties resemble the main human spindle motors kinesin-5 and dynein, revealing the core mechanism of spindle self-organization. It is based on the synergistic interplay of a slow plus-directed symmetric motor and a fast minus-directed asymmetric motor. A hypothetical symmetric minus-directed motor can also support spindle formation together with kinesin-5, but only in a limited and unphysiological parameter range. In agreement with its accessory role in human cells, a minus motor with human kinesin-14 properties does not assemble stable bipolar spindles together with kinesin-5. These results reveal fundamental principles for the self-organization of dynamic bipolar microtubule architectures and highlight how distinct molecular designs of mitotic motors are optimized for their task.
    Keywords:  active matter; bipolar spindle; computer simulation; microtubule network; motor proteins
    DOI:  https://doi.org/10.1073/pnas.2422190122
  7. Proc Natl Acad Sci U S A. 2025 Mar 25. 122(12): e2425225122
    Energy landscape analysis of the development of the chromosome structure across the cell cycle.
    Vinícius G Contessoto, Antonio B Oliveira, Sumitabha Brahmachari, Peter G Wolynes, Michele Di Pierro, José N Onuchic.
      During mitosis, there are significant structural changes in chromosomes. We used a maximum entropy approach to invert experimental Hi-C data to generate effective energy landscapes for chromosomal structures at different stages during the cell cycle. Modeled mitotic structures show a hierarchical organization of helices of helices. High-periodicity loops span hundreds of kilobases or less, while the other low-periodicity ones are larger in genomic separation, spanning several megabases. The structural ensembles reveal a progressive decrease in compartmentalization from interphase to mitosis, accompanied by the appearance of a second diagonal in prometaphase, indicating an organized array of loops. While there is a local tendency to form chiral helices, overall, no preferential left-handed or right-handed chirality appears to develop on the time scale of the cell cycle. Chromatin thus appears to be a liquid crystal containing numerous defects that anneal rather slowly.
    Keywords:  chromatin dynamics; energy landscape; mitotic chromosome
    DOI:  https://doi.org/10.1073/pnas.2425225122
  8. Plant Cell. 2025 Mar 17. pii: koaf053. [Epub ahead of print]
    The kinesin motor POS3 and the microtubule polymerase MOR1 coordinate chromosome congression during mitosis in Arabidopsis.
    Yu Chen, Haofeng Liu, Yuanfeng Li, Xiao Shen, Shuting Li, Lan Yang, Xue An, Pei Lei, Xiaomin Wang, Hongchang Zhang, Jen Sheen, Fei Yu, Xiayan Liu.
      Faithful chromosome segregation during mitosis is crucial for eukaryotic organisms. Centromere-associated protein E (CENP-E), a kinetochore-localized kinesin motor, facilitates chromosome congression during mitosis in animals. However, it remains unclear whether plants rely on kinesins similar to CENP-E for chromosome alignment. In our genetic screens for Arabidopsis (Arabidopsis thaliana) mutants that are hypersensitive to the microtubule-destabilizing drug propyzamide, we identified propyzamide oversensitive3-1 (pos3-1), which harbors a mutation in a kinesin-like protein that shares sequence similarity with the N-terminal region of CENP-E. We demonstrated that POS3 dynamically associates with kinetochores during chromosome congression and segregation in mitosis. Moreover, loss of POS3 results in prolonged mitosis, increased aneuploidy, and misaligned chromosomes near the spindle poles. Unexpectedly, we discovered a direct physical interaction and functional link between POS3 and the microtubule polymerase MICROTUBULE ORGANIZATION1 (MOR1) in regulating chromosome alignment and segregation during mitosis. Finally, we showed that MOR1 is required for the kinetochore localization of POS3 in mitosis. Together, our findings establish the vital role of POS3 in chromosome congression and uncover a functional link between POS3 and MOR1 that is essential for proper chromosome alignment and segregation in plant mitosis.
    DOI:  https://doi.org/10.1093/plcell/koaf053
  9. Mol Cancer Ther. 2025 Mar 19.
    Co-inhibition of Aurora kinase B and SUV4-20H induces synthetic lethality in Wild-type p53 deficient cancer cells.
    Lei Duan, Kelsey M O'Hara, Andrew Caldemeyer, Carl G Maki.
      The tumor suppressor p53 is inactivated by mutation or deletion in over half of all human cancers. Wild-type p53 induces a G1-phase arrest when activated to halt cell proliferation and division. Accordingly, p53 mutated or deficient cancers may be especially sensitive to agents that target proliferating and/or dividing cells. Barasertib (AZD2811) targets the mitotic kinase Aurora B (AURKB) and is in current clinical trials for various cancers. SUV4-20H1 and H2 are histone methyltransferases that can affect mitosis by regulating chromatin compaction in and around centromeres. The drug A196 inhibits SUV4-20H1 and H2. In the current study, we found combined treatment with barasertib plus A196 induces a pronounced synthetic lethality effect in p53-deficient cancer cells. Mechanistically, we found barasertib plus A196 kills p53-deficient cells by inhibiting the spindle assembly checkpoint and inducing massive chromosome missegregations and toxic aneuploidy. Among breast cancer sub-types, triple negative breast cancer cells were the most sensitive to this drug combination. Lastly, we found in two different p53 mutated cell line tumor models that barasertib plus A196 has greater anti-tumor activity than either single agent. Our results suggest co-targeting of AURKB and SUV4-20H1/2 could be effective against p53-mutated or deficient cancers, including TNBCs in which approximately 80% of cases are p53 mutated.
    DOI:  https://doi.org/10.1158/1535-7163.MCT-24-0928
  10. Life Sci Alliance. 2025 Jun;pii: e202402978. [Epub ahead of print]8(6):
    TPX2 lactylation is required for the cell cycle regulation and hepatocellular carcinoma progression.
    Shengzhi Liu, Jin Cai, Xiaoyu Qian, Junjiao Zhang, Yi Zhang, Xiang Meng, Mingjie Wang, Ping Gao, Xiuying Zhong.
      Targeting protein for Xklp2 (TPX2) is critical for mitosis and spindle assembly because of its control of Aurora kinase A (AURKA). However, the regulation of TPX2 activity and its subsequent effects on mitosis and cancer progression remain unclear. Here, we show that TPX2 is lactylated at K249 in hepatocellular carcinoma (HCC) tumour tissues and that this process is regulated by the lactylase CBP and the delactylase HDAC1. Lactate reduction via either shRNAs targeting lactate dehydrogenase A or the lactate dehydrogenase A inhibitor GSK2837808A decreases the level of TPX2 lactylation. Importantly, TPX2 lactylation is required for the cell cycle regulation and tumour growth. Mechanistically, TPX2 lactylation disrupts protein phosphatase 1 (PP1) binding to AURKA, enhances AURKA T288 phosphorylation, and facilitates the cell cycle progression. Overall, our study reveals a previously unappreciated role of TPX2 lactylation in regulating cell cycle progression and HCC tumorigenesis, exposing an important correlation between metabolic reprogramming and cell cycle regulation in HCC.
    DOI:  https://doi.org/10.26508/lsa.202402978
  11. Cell Rep. 2025 Mar 18. pii: S2211-1247(25)00202-5. [Epub ahead of print]44(4): 115431
    REV7 functions with REV3 as a checkpoint protein delaying mitotic entry until DNA replication is completed.
    Katarzyna Sobkowiak, Masaoki Kohzaki, Raphael Böhm, Jonathan Mailler, Florian Huber, Soheila Emamzadah, Laurence Tropia, Sebastian Hiller, Thanos D Halazonetis.
      REV7, also named MAD2B or MAD2L2, is a subunit of the DNA translesion polymerase zeta and also part of the 53BP1-shieldin complex, which is present at sites of DNA double-strand breaks. REV7 has high sequence similarity to the MAD2 spindle assembly checkpoint protein, prompting us to examine whether REV7 has a checkpoint function. We observed that, in chicken and human cells exposed to agents that induce DNA replication stress, REV7 inhibits mitotic entry; this effect is most evident when the canonical DNA replication stress checkpoint, mediated by ATR, is inhibited. Similar to MAD2, REV7 undergoes conformational changes upon ligand binding, and its checkpoint function depends on its ability to homodimerize and bind its ligands. Notably, even in unchallenged cells, deletion of the REV7 gene leads to premature mitotic entry, raising the possibility that the REV7 checkpoint monitors ongoing DNA replication.
    Keywords:  ATR; CP: Molecular biology; DNA polymerase zeta; DNA replication; Mad2L2; Rev1; Rev3; Rev7; cell-cycle checkpoint; mitotic entry
    DOI:  https://doi.org/10.1016/j.celrep.2025.115431
  12. Nat Commun. 2025 Mar 16. 16(1): 2579
    High resolution profiling of cell cycle-dependent protein and phosphorylation abundance changes in non-transformed cells.
    Camilla Rega, Ifigenia Tsitsa, Theodoros I Roumeliotis, Izabella Krystkowiak, Maria Portillo, Lu Yu, Julia Vorhauser, Jonathon Pines, Jörg Mansfeld, Jyoti Choudhary, Norman E Davey.
      The cell cycle governs a precise series of molecular events, regulated by coordinated changes in protein and phosphorylation abundance, that culminates in the generation of two daughter cells. Here, we present a proteomic and phosphoproteomic analysis of the human cell cycle in hTERT-RPE-1 cells using deep quantitative mass spectrometry by isobaric labelling. By analysing non-transformed cells and improving the temporal resolution and coverage of key cell cycle regulators, we present a dataset of cell cycle-dependent protein and phosphorylation site oscillation that offers a foundational reference for investigating cell cycle regulation. These data reveal regulatory intricacies including proteins and phosphorylation sites exhibiting cell cycle-dependent oscillation, and proteins targeted for degradation during mitotic exit. Integrated with complementary resources, our data link cycle-dependent abundance dynamics to functional changes and are accessible through the Cell Cycle database (CCdb), an interactive web-based resource for the cell cycle community.
    DOI:  https://doi.org/10.1038/s41467-025-57537-8
  13. Cancer Res Commun. 2025 Mar 20.
    PLK1 inhibition induces synthetic lethality in Fanconi anemia pathway-deficient acute myeloid leukemia.
    Aditya S Sheth, Ka-Kui Chan, Sheng Liu, Jun Wan, Steven P Angus, Steven D Rhodes, Dana K Mitchell, Christopher Davis, Maya Ridinger, Peter J Croucher, Amer M Zeidan, Aruna Wijeratne, Shaomin Qian, Ngoc Tung Tran, Elizabeth A Sierra Potchanant.
      Overall survival of acute myeloid leukemia (AML) remains limited. Inhibitors of the master mitotic kinase PLK1 have emerged as promising therapeutics, demonstrating efficacy in an undefined subset of AML patients. However, the clinical success of PLK1 inhibitors remains hindered by a lack of predictive biomarkers. The Fanconi anemia (FA) pathway, a tumor-suppressive network comprised of at least 22 genes, is frequently mutated in sporadic AML. Here, we demonstrate that FA pathway disruption sensitizes AML cells to PLK1 inhibition. Mechanistically, we identify novel interactions between PLK1 and both FANCA and FANCD2 at mitotic centromeres. We demonstrate that PLK1 inhibition impairs recruitment of FANCD2 to mitotic centromeres, induces damage to mitotic chromosomes, and triggers mitotic collapse in FANCA-deficient cells. Our findings indicate that PLK1 inhibition targets mitotic vulnerabilities specific to FA pathway-deficient cells and implicate FA pathway mutations as potential biomarkers for the identification of patients likely to benefit from PLK1 inhibitors.
    DOI:  https://doi.org/10.1158/2767-9764.CRC-24-0260
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