KIF2A stabilises intercellular bridge microtubules to maintain mouse embryonic stem cell cytokinesis
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PROVIDER: PRJNA957254 | ENA |
REPOSITORIES: ENA
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Project description:Cytokinesis, the final stage of cell division, serves to physically separate daughter cells. In cultured naïve mouse embryonic stem cells cytokinesis lasts unusually long. Here, we describe a novel function for the kinesin-13 member KIF2A in this process. In genome-engineered mouse embryonic stem cells we find that KIF2A localises to spindle poles during metaphase and regulates spindle length in a manner consistent with its known role as microtubule minus-end depolymerase. By contrast, during cytokinesis we observe tight binding of KIF2A to intercellular bridge microtubules. At this stage KIF2A maintains microtubule length and number, and controls microtubule acetylation. We propose that the conversion of KIF2A from a depolymerase to a stabiliser is driven both by the inhibition of its ATPase activity, which increases lattice affinity, and a preference for compacted lattices. In turn, KIF2A might maintain the compacted microtubule state at the intercellular bridge, thereby dampening acetylation. As KIF2A depletion causes pluripotency problems and affects mRNA homeostasis our results furthermore indicate that KIF2A-mediated microtubule stabilisation prolongs cytokinesis to maintain pluripotency.
2025-05-06 | GSE230038 | GEO
Project description:During cytokinesis, the intercellular bridge (ICB) connecting the daughter cells experiences pulling forces, which delay abscission by preventing the assembly of the ESCRT scission machinery. Abscission is thus triggered by tension release, but how ICB tension is controlled is unknown. Here, we report that caveolae, which are known to regulate membrane tension upon mechanical stress in interphase cells, are located at the midbody, at the abscission site, and at the ICB/cell interface in dividing cells. Functionally, the loss of caveolae delays ESCRT-III recruitment during cytokinesis and impairs abscission. This is the consequence of a twofold increase of ICB tension measured by laser ablation, associated with a local increase in myosin II activity at the ICB/cell interface. We thus propose that caveolae buffer membrane tension and limit contractibility at the ICB to promote ESCRT-III assembly and cytokinetic abscission. Together, this work reveals an unexpected connection between caveolae and the ESCRT machinery and the first role of caveolae in cell division.
| S-EPMC9007517 | biostudies-literature
Project description:The midbody is an organelle assembled at the intercellular bridge connecting the two daughter cells at the end of mitosis. It is essential for the final separation of the daughter cells and involved in other important processes, including cell fate, pluripotency, apical-basal polarity, and cilium/lumen formation. The midbody is composed of numerous proteins with diverse functions distributed in a precise pattern. Here we report the first characterization of the midbody protein-protein interaction network (interactome), which provides an extremely valuable resource for understanding its multiple roles. Analysis of this midbody interactome led to the discovery that PP1/MYPT1 phosphatase regulates microtubule dynamics in late cytokinesis through de-phosphorylation of the kinesin MKLP1/KIF23, a finding that unexpectedly expands the temporal window of activity of this phosphatase during mitosis.
2019-08-29 | PXD012374 | Pride
Project description:Canonical Wnt signaling plays critical roles in development and tissue renewal by regulating β-catenin target genes. Recent evidence showed that β-catenin-independent Wnt signaling is also required for faithful execution of mitosis. This mitotic Wnt signaling functions through Wnt-dependent stabilization of proteins (Wnt/STOP), as well as through components of the LRP6 signalosome. However, the targets and specific functions of mitotic Wnt signaling still remain uncharacterized. Using phosphoproteomics, we identified that Wnt signaling regulates the microtubule depolymerase KIF2A during mitosis. We found that Dishevelled recruits KIF2A via its N-terminal and motor domains, which is further promoted upon LRP6 signalosome formation during mitosis. We show that Wnt signaling modulates KIF2A interaction with PLK1, which is critical for KIF2A localization and the assembly of a bipolar mitotic spindle. Accordingly, Wnt signaling promotes chromosome congression during metaphase by monitoring KIF2A protein levels at the spindle poles both in somatic cells and in pluripotent stem cells. Our findings highlight a novel function of Wnt signaling during cell division, which could have important implications for genome maintenance, notably in stem cells.
2021-11-17 | PXD022724 | Pride
Project description:Germ cell connectivity via intercellular bridges is a widely conserved feature but its functional significance is poorly understood. Intercellular bridges are essential for fertility in male mice as genetic ablation of a critical bridge component, TEX14, causes loss of germ cell connectivity and meiotic failure, however the underlying reasons are unknown. A screen for meiosis-defective mouse mutants yielded a sterile mutant harboring a point mutation in Tex14 that leads to a partial loss of germ cell intercellular bridges. We utilized the Tex14 hypomorphs with reduced intercellular bridges, along with Tex14-null mice that completely lack bridges to examine the roles of germ cell connectivity during adult spermatogenesis. Complete or partial loss of intercellular bridges does not severely deplete spermatogonia, but spermatocytes are unable to undergo meiotic DNA replication and enter meiotic prophase. Phenotypic severity correlates with the extent of intercellular bridge depletion, with Tex14 hypomorphs containing a relatively larger number of spermatocytes undergoing meiosis, thus allowing us to assess impacts on meiotic progression. Tex14-deficient germ cells that enter prophase form meiotic breaks and initiate synapsis, but later exhibit synaptic failures and retain unrepaired breaks. Strikingly, Tex14-deficient germ cells derepress LINE1 retrotransposons and accumulate LINE1-encoded proteins during meiosis. Single-cell RNA-sequencing of testes from Tex14 hypomorphs show that intercellular bridge depletion modestly impacts the RNA landscape in early germ cell stages, while mutant cells that progress to late spermatocyte and post-meiotic spermatid stages broadly upregulate retrotransposons and dysregulate gene expression. RNA-sequencing confirms extensive sharing of transcripts between normal spermatids and demonstrates its partial attenuation in Tex14 hypomorphs, indicating that intercellular bridges enable exchange of cytoplasmic material between connected germ cells in testes. Tex14 hypomorphs display a progressive decline in germ cell numbers starting from the spermatocyte stage, with a complete lack of elongating spermatids, and are therefore sterile. Our findings reveal that the regulation of meiosis is non-cell-intrinsic and inform a model in which intercellular bridges orchestrate critical meiotic events and protect germline genome integrity during spermatogenesis, possibly by facilitating the exchange of regulatory factors.
2025-01-06 | GSE274959 | GEO
Project description:Comparison of the Dorsal root ganglia (DRG) transcriptome of WT and Kif2a conditional knockout animals at one months of age
2023-10-23 | GSE240557 | GEO
Project description:Comparison of the Dorsal root ganglia (DRG) transcriptome of WT and Kif2a conditional knockout animals at six months of age
2023-10-23 | GSE222924 | GEO
Project description:Comparison of the Dorsal root ganglia(DRG) transcriptome of WT and Kif2a conditional knockout animals at three months of age
2023-10-23 | GSE222923 | GEO
Project description:Cellular abscission is the final step of cytokinesis that leads to the physical separation of the two daughter cells. The scaffold protein ALIX and the ESCRT-I protein TSG101 contribute to recruiting ESCRT-III to the midbody, which orchestrates the final membrane scission of the intercellular bridge. Here, we addressed the transport mechanisms of ALIX and ESCRT-III subunit CHMP4B to the midbody. Structured illumination microscopy revealed gradual accumulation of ALIX at the midbody, resulting in the formation of spiral-like structures extending from the midbody to the abscission site, which strongly co-localized with CHMP4B. Live-cell microscopy uncovered that ALIX appeared together with CHMP4B in vesicular structures, whose motility was microtubule-dependent. Depletion of ALIX led to structural alterations of the midbody and delayed recruitment of CHMP4B, resulting in delayed abscission. Likewise, depletion of the kinesin-1 motor KIF5B reduced the motility of ALIX-positive vesicles and delayed midbody recruitment of ALIX, TSG101 and CHMP4B, accompanied by impeded abscission. We propose that ALIX, TSG101 and CHMP4B are associated with endosomal vesicles transported on microtubules by kinesin-1 to the cytokinetic bridge and midbody, thereby contributing to their function in abscission.
| S-EPMC10390626 | biostudies-literature
Project description:Rac1, a member of the small G protein Rho family, has been implicated in neurodegenerative diseases. However, its role in axon degeneration is not fully understood. Here we found that activation of Rac1 exacerbated axonal transport damage in an experimental glaucoma model. Inhibiting Rac1 activity by genetic or pharmacological methods alleviated the dysfunction of axonal transport and improved the integrity of microtubule by upregulating the expression of β-III tubulin and myelin basic protein. Rac1 interacted with Sirt1, a key molecule of Wallerian degeneration, which regulated the activity of PAK1, a downstream molecule of Rac1. Furthermore, Rac1 modulated Kif motors at the transcriptional level, among which Kif2a, a lysosome-location regulator, was negatively regulated by Rac1. Intravitreal injection of Kif2a siRNA reversed the improvement of Rac1 inhibition-mediated axonal transport through reducing autophagolysosomes. Our results suggest that Rac1/Kif2a accelerates the process of RGC axon degeneration by impairing the autophagic flux in glaucoma, which may be an intriguing therapy target for glaucoma.
2024-12-01 | GSE247696 | GEO