Accurate nuclear position is essential for each daughter cell to receive one DNA complement. In budding yeast, a surveillance mechanism known as the spindle position checkpoint ensures that exit from mitosis only occurs when the anaphase nucleus is positioned along the mother-bud axis. We identified the protein kinase Kin4 as a component of the spindle position checkpoint. KIN4 prevents exit from mitosis in cells with mispositioned nuclei by inhibiting the mitotic exit network (MEN), a GTPase signaling cascade that promotes exit from mitosis. Kin4 is active in cells with mispositioned nuclei and predominantly localizes to mother cells, where it is ideally situated to inhibit MEN signaling at spindle pole bodies (SPBs) when anaphase spindle elongation occurs within the mother cell.
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http://dx.doi.org/10.1016/j.molcel.2005.06.005 | DOI Listing |
J Biol Chem
January 2025
Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio, USA. Electronic address:
Selective inhibitors that target cyclin dependent kinases 4 and 6 (CDK4/6i) are FDA approved for treatment of a subset of breast cancers and are being evaluated in numerous clinical trials for other cancers. Despite this advance, a subset of tumors are intrinsically resistant to these drugs and acquired resistance is nearly inevitable. Recent mechanistic evidence suggests that in addition to stalling the cell cycle, the anti-tumor effects of CDK4/6i involve the induction of chromosomal instability (CIN).
View Article and Find Full Text PDFCurr Biol
January 2025
Department of Cell Biology, Duke University Medical Center, Durham, NC 27705, USA; Duke Center for Quantitative Living Systems, Duke University Medical Center, Durham, NC 27710, USA. Electronic address:
Anaphase is tightly controlled spatiotemporally to ensure proper separation of chromosomes. The mitotic spindle, the self-organized microtubule structure driving chromosome segregation, scales in size with the available cytoplasm. Yet, the relationship between spindle size and chromosome movement remains poorly understood.
View Article and Find Full Text PDFNat Cell Biol
January 2025
CNRS UMR144 - UMR3664, Institut Curie, Sorbonne Université, PSL Research University, Paris, France.
Errors during cell division lead to aneuploidy, which is associated with genomic instability and cell transformation. In response to aneuploidy, cells activate the tumour suppressor p53 to elicit a surveillance mechanism that halts proliferation and promotes senescence. The molecular sensors that trigger this checkpoint are unclear.
View Article and Find Full Text PDFCell Death Dis
January 2025
Mater Research Institute, The University of Queensland, Brisbane, QLD, Australia.
Polyploidy is a common outcome of chemotherapies, but there is conflicting evidence as to whether polyploidy is an adverse, benign or even favourable outcome. We show Aurora B kinase inhibitors efficiently promote polyploidy in many cell types, resulting in the cell cycle exit in RB and p53 functional cells, but hyper-polyploidy in cells with loss of RB and p53 function. These hyper-polyploid cells (>8n DNA content) are viable but have lost long-term proliferative potential in vitro and fail to form tumours in vivo.
View Article and Find Full Text PDFCells Dev
January 2025
Université Paris-Saclay, Hôpital Kremlin Bicêtre, U1195, Inserm, 94276 Le Kremlin Bicêtre, France. Electronic address:
The temporal control of mitotic exit of individual Schwann cells (SCs) is essential for radial sorting and peripheral myelination. However, it remains unknown when, during their multiple rounds of division, SCs initiate myelin signaling in vivo. By manipulating SC division during development, we report that when SCs skip their division during migration, but not during radial sorting, they fail to myelinate peripheral axons.
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