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Cells Aug 2022Cell cycle and cell adhesion are two interdependent cellular processes regulating each other, reciprocally, in every cell cycle phase. The cell adhesion to the... (Review)
Review
Cell cycle and cell adhesion are two interdependent cellular processes regulating each other, reciprocally, in every cell cycle phase. The cell adhesion to the extracellular matrix (ECM) via integrin receptors triggers signaling pathways required for the cell cycle progression; the passage from the G1 to S phase and the completion of cytokinesis are the best-understood events. Growing evidence, however, suggests more adhesion-dependent regulatory aspects of the cell cycle, particularly during G2 to M transition and early mitosis. Conversely, the cell cycle machinery regulates cell adhesion in manners recently shown driven mainly by cyclin-dependent kinase 1 (CDK1). This review summarizes the recent findings regarding the role of integrin-mediated cell adhesion and its downstream signaling components in regulating the cell cycle, emphasizing the cell cycle progression through the G2 and early M phases. Further investigations are required to raise our knowledge about the molecular mechanisms of crosstalk between cell adhesion and the cell cycle in detail.
Topics: Cell Adhesion; Cell Cycle; Cell Cycle Checkpoints; Integrins; Mitosis
PubMed: 36010598
DOI: 10.3390/cells11162521 -
The Journal of Cell Biology May 2023Enduring chromosome segregation errors represent potential threats to genomic stability due to eventual chromosome copy number alterations (aneuploidy) and formation of... (Review)
Review
Enduring chromosome segregation errors represent potential threats to genomic stability due to eventual chromosome copy number alterations (aneuploidy) and formation of micronuclei-key intermediates of a rapid mutational process known as chromothripsis that is found in cancer and congenital disorders. The spindle assembly checkpoint (SAC) has been viewed as the sole surveillance mechanism that prevents chromosome segregation errors during mitosis and meiosis. However, different types of chromosome segregation errors stemming from incorrect kinetochore-microtubule attachments satisfy the SAC and are more frequent than previously anticipated. Remarkably, recent works have unveiled that most of these errors are corrected during anaphase and only rarely result in aneuploidy or formation of micronuclei. Here, we discuss recent progress in our understanding of the origin and fate of chromosome segregation errors that satisfy the SAC and shed light on the surveillance, correction, and clearance mechanisms that prevent their transmission, to preserve genomic stability.
Topics: Humans; Anaphase; Aneuploidy; Chromosome Segregation; Kinetochores; Microtubules; Mitosis; Spindle Apparatus; Genomic Instability
PubMed: 37017932
DOI: 10.1083/jcb.202301106 -
Science (New York, N.Y.) Aug 2023Nonhomologous end-joining (NHEJ) and homologous recombination (HR) are the primary pathways for repairing DNA double-strand breaks (DSBs) during interphase, whereas...
Nonhomologous end-joining (NHEJ) and homologous recombination (HR) are the primary pathways for repairing DNA double-strand breaks (DSBs) during interphase, whereas microhomology-mediated end-joining (MMEJ) has been regarded as a backup mechanism. Through CRISPR-Cas9-based synthetic lethal screens in cancer cells, we identified subunits of the 9-1-1 complex (RAD9A-RAD1-HUS1) and its interacting partner, RHINO, as crucial MMEJ factors. We uncovered an unexpected function for RHINO in restricting MMEJ to mitosis. RHINO accumulates in M phase, undergoes Polo-like kinase 1 (PLK1) phosphorylation, and interacts with polymerase θ (Polθ), enabling its recruitment to DSBs for subsequent repair. Additionally, we provide evidence that MMEJ activity in mitosis repairs persistent DSBs that originate in S phase. Our findings offer insights into the synthetic lethal relationship between the genes and and and the synergistic effect of Polθ and poly(ADP-ribose) polymerase (PARP) inhibitors.
Topics: Humans; Cell Cycle Proteins; DNA Breaks, Double-Stranded; DNA End-Joining Repair; Exonucleases; HEK293 Cells; Mitosis; Poly(ADP-ribose) Polymerases
PubMed: 37440612
DOI: 10.1126/science.adh3694 -
Nature Feb 2021Whole-genome doubling (WGD) is common in human cancers, occurring early in tumorigenesis and generating genetically unstable tetraploid cells that fuel tumour...
Whole-genome doubling (WGD) is common in human cancers, occurring early in tumorigenesis and generating genetically unstable tetraploid cells that fuel tumour development. Cells that undergo WGD (WGD cells) must adapt to accommodate their abnormal tetraploid state; however, the nature of these adaptations, and whether they confer vulnerabilities that can be exploited therapeutically, is unclear. Here, using sequencing data from roughly 10,000 primary human cancer samples and essentiality data from approximately 600 cancer cell lines, we show that WGD gives rise to common genetic traits that are accompanied by unique vulnerabilities. We reveal that WGD cells are more dependent than WGD cells on signalling from the spindle-assembly checkpoint, DNA-replication factors and proteasome function. We also identify KIF18A, which encodes a mitotic kinesin protein, as being specifically required for the viability of WGD cells. Although KIF18A is largely dispensable for accurate chromosome segregation during mitosis in WGD cells, its loss induces notable mitotic errors in WGD cells, ultimately impairing cell viability. Collectively, our results suggest new strategies for specifically targeting WGD cancer cells while sparing the normal, non-transformed WGD cells that comprise human tissue.
Topics: Abnormal Karyotype; Breast Neoplasms; Cell Line, Tumor; Female; Genes, Lethal; Genome, Human; Humans; Kinesins; M Phase Cell Cycle Checkpoints; Male; Mitosis; Neoplasms; Proteasome Endopeptidase Complex; Reproducibility of Results; Spindle Apparatus; Tetraploidy
PubMed: 33505027
DOI: 10.1038/s41586-020-03133-3 -
Journal of Cell Science Sep 2020Human retinal pigment epithelial-1 (RPE-1) cells are increasingly being used as a model to study mitosis because they represent a non-transformed alternative to cancer...
Human retinal pigment epithelial-1 (RPE-1) cells are increasingly being used as a model to study mitosis because they represent a non-transformed alternative to cancer cell lines, such as HeLa cervical adenocarcinoma cells. However, the lack of an efficient method to synchronize RPE-1 cells in mitosis precludes their application for large-scale biochemical and proteomics assays. Here, we report a protocol to synchronize RPE-1 cells based on sequential treatments with the Cdk4 and Cdk6 inhibitor PD 0332991 (palbociclib) and the microtubule-depolymerizing drug nocodazole. With this method, the vast majority (80-90%) of RPE-1 cells arrested at prometaphase and exited mitosis synchronously after release from nocodazole. Moreover, the cells fully recovered and re-entered the cell cycle after the palbociclib-nocodazole block. Finally, we show that this protocol could be successfully employed for the characterization of the protein-protein interaction network of the kinetochore protein Ndc80 by immunoprecipitation coupled with mass spectrometry. This synchronization method significantly expands the versatility and applicability of RPE-1 cells to the study of cell division and might be applied to other cell lines that do not respond to treatments with DNA synthesis inhibitors.
Topics: Humans; Kinetochores; Mitosis; Nocodazole; Prometaphase; Retinal Pigments
PubMed: 32878943
DOI: 10.1242/jcs.247940 -
Current Opinion in Structural Biology Aug 2023Chromosomes transform during the cell cycle, allowing transcription and replication during interphase and chromosome segregation during mitosis. Morphological changes... (Review)
Review
Chromosomes transform during the cell cycle, allowing transcription and replication during interphase and chromosome segregation during mitosis. Morphological changes are thought to be driven by the combined effects of DNA loop extrusion and a chromatin solubility phase transition. By extruding the chromatin fibre into loops, condensins enrich at an axial core and provide resistance to spindle pulling forces. Mitotic chromosomes are further compacted by deacetylation of histone tails, rendering chromatin insoluble and resistant to penetration by microtubules. Regulation of surface properties by Ki-67 allows independent chromosome movement in early mitosis and clustering during mitotic exit. Recent progress has provided insight into how the extraordinary material properties of chromatin emerge from these activities, and how these properties facilitate faithful chromosome segregation.
Topics: Chromosomes; Chromatin; Mitosis; Histones; Chromosome Segregation
PubMed: 37279615
DOI: 10.1016/j.sbi.2023.102617 -
Molecular Cell May 2023Cell cycle and metabolism are intimately intertwined, but how metabolites directly regulate cell-cycle machinery remains elusive. Liu et al. reveal that glycolysis...
Cell cycle and metabolism are intimately intertwined, but how metabolites directly regulate cell-cycle machinery remains elusive. Liu et al. reveal that glycolysis end-product lactate directly binds and inhibits the SUMO protease SENP1 to govern the E3 ligase activity of the anaphase-promoting complex, leading to efficient mitotic exit in proliferative cells.
Topics: Anaphase; Lactic Acid; Mitosis; Anaphase-Promoting Complex-Cyclosome; Cell Cycle Proteins
PubMed: 37207623
DOI: 10.1016/j.molcel.2023.04.013 -
Seminars in Cell & Developmental Biology Sep 2021Our understanding of the structure and function of mitotic chromosomes has come a long way since these iconic objects were first recognized more than 140 years ago,... (Review)
Review
Our understanding of the structure and function of mitotic chromosomes has come a long way since these iconic objects were first recognized more than 140 years ago, though many details remain to be elucidated. In this chapter, we start with the early history of chromosome studies and then describe the path that led to our current understanding of the formation and structure of mitotic chromosomes. We also discuss some of the remaining questions. It is now well established that each mitotic chromatid consists of a central organizing region containing a so-called "chromosome scaffold" from which loops of DNA project radially. Only a few key non-histone proteins and protein complexes are required to form the chromosome: topoisomerase IIα, cohesin, condensin I and condensin II, and the chromokinesin KIF4A. These proteins are concentrated along the axis of the chromatid. Condensins I and II are primarily responsible for shaping the chromosome and the scaffold, and they produce the loops of DNA by an ATP-dependent process known as loop extrusion. Modelling of Hi-C data suggests that condensin II adopts a spiral staircase arrangement with an extruded loop extending out from each step in a roughly helical pattern. Condensin I then forms loops nested within these larger condensin II loops, thereby giving rise to the final compaction of the mitotic chromosome in a process that requires Topo IIα.
Topics: Chromosomes; Humans; Mitosis
PubMed: 33836947
DOI: 10.1016/j.semcdb.2021.03.014 -
Nature Jun 2023Complex genome rearrangements can be generated by the catastrophic pulverization of missegregated chromosomes trapped within micronuclei through a process known as...
Complex genome rearrangements can be generated by the catastrophic pulverization of missegregated chromosomes trapped within micronuclei through a process known as chromothripsis. As each chromosome contains a single centromere, it remains unclear how acentric fragments derived from shattered chromosomes are inherited between daughter cells during mitosis. Here we tracked micronucleated chromosomes with live-cell imaging and show that acentric fragments cluster in close spatial proximity throughout mitosis for asymmetric inheritance by a single daughter cell. Mechanistically, the CIP2A-TOPBP1 complex prematurely associates with DNA lesions within ruptured micronuclei during interphase, which poises pulverized chromosomes for clustering upon mitotic entry. Inactivation of CIP2A-TOPBP1 caused acentric fragments to disperse throughout the mitotic cytoplasm, stochastically partition into the nucleus of both daughter cells and aberrantly misaccumulate as cytoplasmic DNA. Mitotic clustering facilitates the reassembly of acentric fragments into rearranged chromosomes lacking the extensive DNA copy-number losses that are characteristic of canonical chromothripsis. Comprehensive analysis of pan-cancer genomes revealed clusters of DNA copy-number-neutral rearrangements-termed balanced chromothripsis-across diverse tumour types resulting in the acquisition of known cancer driver events. Thus, distinct patterns of chromothripsis can be explained by the spatial clustering of pulverized chromosomes from micronuclei.
Topics: Humans; Centromere; Chromosomes, Human; Chromothripsis; DNA; DNA Copy Number Variations; Interphase; Micronuclei, Chromosome-Defective; Mitosis; Neoplasms
PubMed: 37165191
DOI: 10.1038/s41586-023-05974-0 -
Nucleus (Austin, Tex.) Dec 2022The kinetochore is a large proteinaceous structure assembled on the centromeres of chromosomes. The complex machinery links chromosomes to the mitotic spindle and is... (Review)
Review
The kinetochore is a large proteinaceous structure assembled on the centromeres of chromosomes. The complex machinery links chromosomes to the mitotic spindle and is essential for accurate chromosome segregation during cell division. The kinetochore is composed of two submodules: the inner and outer kinetochore. The inner kinetochore is assembled on centromeric chromatin and persists with centromeres throughout the cell cycle. The outer kinetochore attaches microtubules to the inner kinetochore, and assembles only during mitosis. The review focuses on recent advances in our understanding of the mechanisms governing the proper assembly of the outer kinetochore during mitosis and highlights open questions for future investigation.
Topics: Cell Cycle Checkpoints; Centromere; Chromosome Segregation; Kinetochores; Mitosis; Spindle Apparatus
PubMed: 36037227
DOI: 10.1080/19491034.2022.2115246