bims-micesi Biomed News
on Mitotic cell signalling
Issue of 2022–07–17
thirteen papers selected by
Valentina Piano, Max Planck Institute of Molecular Physiology
  1. Cell division: The science friction of chromosome attachment.
  2. Structural Organization and Function of the Golgi Ribbon During Cell Division.
  3. Dynamic cell cycle-dependent phosphorylation modulates CENP-L-CENP-N centromere recruitment.
  4. The Role of the APC/C and Its Coactivators Cdh1 and Cdc20 in Cancer Development and Therapy.
  5. Mitotic checkpoint gene expression is tuned by codon usage bias.
  6. Self-Assembly of Microtubule Tactoids.
  7. Kinesin KIF15 regulates tubulin acetylation and spindle assembly checkpoint in mouse oocyte meiosis.
  8. Establishment of centromere identity is dependent on nuclear spatial organization.
  9. Nuclear chromosome locations dictate segregation error frequencies.
  10. Coordinating gene expression during the cell cycle.
  11. A sumoylation program is essential for maintaining the mitotic fidelity in proliferating mantle cell lymphoma cells.
  12. A ROS-dependent mechanism promotes CDK2 phosphorylation to drive progression through S phase.
  13. Human neural progenitors establish a diffusion barrier in the ER membrane during cell division.
  1. Curr Biol. 2022 Jul 11. pii: S0960-9822(22)00848-X. [Epub ahead of print]32(13): R744-R746
    Cell division: The science friction of chromosome attachment.
    Cédric Castrogiovanni, Patrick Meraldi.
      During mitosis, chromosomes must bind spindle microtubules via kinetochores in a stable yet dynamic manner to ensure rapid frictionless movements. A recent study identifies the first complex that specifically reduces friction in the kinetochore-microtubule interface to ensure efficient chromosome segregation.
    DOI:  https://doi.org/10.1016/j.cub.2022.05.045
  2. Front Cell Dev Biol. 2022 ;10 925228
    Structural Organization and Function of the Golgi Ribbon During Cell Division.
    Inmaculada Ayala, Antonino Colanzi.
      The Golgi complex has a central role in the secretory traffic. In vertebrate cells it is generally organized in polarized stacks of cisternae that are laterally connected by membranous tubules, forming a structure known as Golgi ribbon. The steady state ribbon arrangement results from a dynamic equilibrium between formation and cleavage of the membrane tubules connecting the stacks. This balance is of great physiological relevance as the unlinking of the ribbon during G2 is required for mitotic entry. A block of this process induces a potent G2 arrest of the cell cycle, indicating that a mitotic "Golgi checkpoint" controls the correct pre-mitotic segregation of the Golgi ribbon. Then, after mitosis onset, the Golgi stacks undergo an extensive disassembly, which is necessary for proper spindle formation. Notably, several Golgi-associated proteins acquire new roles in spindle formation and mitotic progression during mitosis. Here we summarize the current knowledge about the basic principle of the Golgi architecture and its functional relationship with cell division to highlight crucial aspects that need to be addressed to help us understand the physiological significance of the ribbon and the pathological implications of alterations of this organization.
    Keywords:  Golgi ribbon; cancer; checkpoint; mitosis; spindle
    DOI:  https://doi.org/10.3389/fcell.2022.925228
  3. Mol Biol Cell. 2022 Jul 13. mbcE22060239
    Dynamic cell cycle-dependent phosphorylation modulates CENP-L-CENP-N centromere recruitment.
    Alexandra P Navarro, Iain M Cheeseman.
      The kinetochore is a macromolecular structure that is required to ensure proper chromosome segregation during each cellular division. The kinetochore is assembled upon a platform of the 16-subunit Constitutive Centromere Associated Network (CCAN), which is present at centromeres throughout the cell cycle. The nature and regulation of CCAN assembly, interactions, and dynamics required to facilitate changing centromere properties and requirements remain to be fully elucidated. The CENP-LN complex is a CCAN component that displays a unique cell cycle-dependent localization behavior, peaking in S phase. Here, we demonstrate that phosphorylation of CENP-L and CENP-N controls CENP-LN complex formation and localization in a cell cycle-dependent manner. Mimicking constitutive phosphorylation of either CENP-L or CENP-N or simultaneously preventing phosphorylation of both proteins prevents CENP-LN localization and disrupts chromosome segregation. Together, our work suggests that cycles of phosphorylation and dephosphorylation are critical for CENP-LN complex recruitment and dynamics at kinetochores to enable cell cycle-dependent CCAN reorganization.
    DOI:  https://doi.org/10.1091/mbc.E22-06-0239
  4. Front Genet. 2022 ;13 941565
    The Role of the APC/C and Its Coactivators Cdh1 and Cdc20 in Cancer Development and Therapy.
    Christine Greil, Monika Engelhardt, Ralph Wäsch.
      To sustain genomic stability by correct DNA replication and mitosis, cell cycle progression is tightly controlled by the cyclic activity of cyclin-dependent kinases, their binding to cyclins in the respective phase and the regulation of cyclin levels by ubiquitin-dependent proteolysis. The spindle assembly checkpoint plays an important role at the metaphase-anaphase transition to ensure a correct separation of sister chromatids before cytokinesis and to initiate mitotic exit, as an incorrect chromosome distribution may lead to genetically unstable cells and tumorigenesis. The ubiquitin ligase anaphase-promoting complex or cyclosome (APC/C) is essential for these processes by mediating the proteasomal destruction of cyclins and other important cell cycle regulators. To this end, it interacts with the two regulatory subunits Cdh1 and Cdc20. Both play a role in tumorigenesis with Cdh1 being a tumor suppressor and Cdc20 an oncogene. In this review, we summarize the current knowledge about the APC/C-regulators Cdh1 and Cdc20 in tumorigenesis and potential targeted therapeutic approaches.
    Keywords:  APC/C; Cdh1; antimitotic therapy; mitotic exit; mitotic slippage; spindle assembly checkpoint
    DOI:  https://doi.org/10.3389/fgene.2022.941565
  5. EMBO J. 2022 Jul 11. e107896
    Mitotic checkpoint gene expression is tuned by codon usage bias.
    Eric Esposito, Douglas E Weidemann, Jessie M Rogers, Claire M Morton, Erod Keaton Baybay, Jing Chen, Silke Hauf.
      The mitotic checkpoint (also called spindle assembly checkpoint, SAC) is a signaling pathway that safeguards proper chromosome segregation. Correct functioning of the SAC depends on adequate protein concentrations and appropriate stoichiometries between SAC proteins. Yet very little is known about the regulation of SAC gene expression. Here, we show in the fission yeast Schizosaccharomyces pombe that a combination of short mRNA half-lives and long protein half-lives supports stable SAC protein levels. For the SAC genes mad2+ and mad3+ , their short mRNA half-lives are caused, in part, by a high frequency of nonoptimal codons. In contrast, mad1+ mRNA has a short half-life despite a higher frequency of optimal codons, and despite the lack of known RNA-destabilizing motifs. Hence, different SAC genes employ different strategies of expression. We further show that Mad1 homodimers form co-translationally, which may necessitate a certain codon usage pattern. Taken together, we propose that the codon usage of SAC genes is fine-tuned to ensure proper SAC function. Our work shines light on gene expression features that promote spindle assembly checkpoint function and suggests that synonymous mutations may weaken the checkpoint.
    Keywords:  co-translational assembly; gene expression noise; mRNA decay; mitosis; spindle assembly checkpoint
    DOI:  https://doi.org/10.15252/embj.2021107896
  6. J Vis Exp. 2022 Jun 23.
    Self-Assembly of Microtubule Tactoids.
    Prashali Chauhan, Sumon Sahu, Niaz Goodbee, Sophia Martin, Hong Beom Lee, Ruell Branch, Jennifer M Schwarz, Jennifer L Ross.
      The cytoskeleton is responsible for major internal organization and re-organization within the cell, all without a manager to direct the changes. This is especially the case during mitosis or meiosis, where the microtubules form the spindle during cell division. The spindle is the machinery used to segregate genetic material during cell division. Toward creating self-organized spindles in vitro, we recently developed a technique to reconstitute microtubules into spindle-like assemblies with a minimal set of microtubule-associated proteins and crowding agents. Specifically, MAP65 was used, which is an antiparallel microtubule crosslinker from plants, a homolog of Ase1 from yeast and PRC1 from mammalian organisms. This crosslinker self-organizes microtubules into long, thin, spindle-like microtubule self-organized assemblies. These assemblies are also similar to liquid crystal tactoids, and microtubules could be used as mesoscale mesogens. Here, protocols are presented for creating these microtubule tactoids, as well as for characterizing the shape of the assemblies using fluorescence microscopy and the mobility of the constituents using fluorescence recovery after photobleaching.
    DOI:  https://doi.org/10.3791/63952
  7. Cell Mol Life Sci. 2022 Jul 14. 79(8): 422
    Kinesin KIF15 regulates tubulin acetylation and spindle assembly checkpoint in mouse oocyte meiosis.
    Yuan-Jing Zou, Meng-Meng Shan, Xiang Wan, Jing-Cai Liu, Kun-Huan Zhang, Jia-Qian Ju, Chun-Hua Xing, Shao-Chen Sun.
      Microtubule dynamics ensure multiple cellular events during oocyte meiosis, which is critical for the fertilization and early embryo development. KIF15 (also termed Hklp2) is a member of kinesin-12 family motor proteins, which participates in Eg5-related bipolar spindle formation in mitosis. In present study, we explored the roles of KIF15 in mouse oocyte meiosis. KIF15 expressed during oocyte maturation and localized with microtubules. Depletion or inhibition of KIF15 disturbed meiotic cell cycle progression, and the oocytes which extruded the first polar body showed a high aneuploidy rate. Further analysis showed that disruption of KIF15 did not affect spindle morphology but resulted in chromosome misalignment. This might be due to the reduced stability of the K-fibers, which further induced the loss of kinetochore-microtubule attachment and activated spindle assembly checkpoint, showing with the failed release of Bub3 and BubR1. Based on mass spectroscopy analysis and coimmunoprecipitation data we showed that KIF15 was responsible for recruiting HDAC6, NAT10 and SIRT2 to maintain the acetylated tubulin level, which further affected tubulin acetylation for microtubule stability. Taken together, these results suggested that KIF15 was essential for the microtubule acetylation and cell cycle control during mouse oocyte meiosis.
    Keywords:  Aneuploidy; Cell cycle; Meiosis; Microtubule; Oocyte
    DOI:  https://doi.org/10.1007/s00018-022-04447-3
  8. Curr Biol. 2022 Jul 05. pii: S0960-9822(22)01010-7. [Epub ahead of print]
    Establishment of centromere identity is dependent on nuclear spatial organization.
    Weifang Wu, Toni McHugh, David A Kelly, Alison L Pidoux, Robin C Allshire.
      The establishment of centromere-specific CENP-A chromatin is influenced by epigenetic and genetic processes. Central domain sequences from fission yeast centromeres are preferred substrates for CENP-ACnp1 incorporation, but their use is context dependent, requiring adjacent heterochromatin. CENP-ACnp1 overexpression bypasses heterochromatin dependency, suggesting that heterochromatin ensures exposure to conditions or locations permissive for CENP-ACnp1 assembly. Centromeres cluster around spindle-pole bodies (SPBs). We show that heterochromatin-bearing minichromosomes localize close to SPBs, consistent with this location promoting CENP-ACnp1 incorporation. We demonstrate that heterochromatin-independent de novo CENP-ACnp1 chromatin assembly occurs when central domain DNA is placed near, but not far from, endogenous centromeres or neocentromeres. Moreover, direct tethering of central domain DNA at SPBs permits CENP-ACnp1 assembly, suggesting that the nuclear compartment surrounding SPBs is permissive for CENP-ACnp1 incorporation because target sequences are exposed to high levels of CENP-ACnp1 and associated assembly factors. Thus, nuclear spatial organization is a key epigenetic factor that influences centromere identity.
    Keywords:  CENP-A; S. pombe; centromere identity; fission yeast; heterochromatin; spatial organization; spindle-pole body
    DOI:  https://doi.org/10.1016/j.cub.2022.06.048
  9. Nature. 2022 Jul 13.
    Nuclear chromosome locations dictate segregation error frequencies.
    Sjoerd J Klaasen, My Anh Truong, Richard H van Jaarsveld, Isabella Koprivec, Valentina Štimac, Sippe G de Vries, Patrik Risteski, Snježana Kodba, Kruno Vukušić, Kim L de Luca, Joana F Marques, Elianne M Gerrits, Bjorn Bakker, Floris Foijer, Jop Kind, Iva M Tolić, Susanne M A Lens, Geert J P L Kops.
      Chromosome segregation errors during cell divisions generate aneuploidies and micronuclei, which can undergo extensive chromosomal rearrangements such as chromothripsis1-5. Selective pressures then shape distinct aneuploidy and rearrangement patterns-for example, in cancer6,7-but it is unknown whether initial biases in segregation errors and micronucleation exist for particular chromosomes. Using single-cell DNA sequencing8 after an error-prone mitosis in untransformed, diploid cell lines and organoids, we show that chromosomes have different segregation error frequencies that result in non-random aneuploidy landscapes. Isolation and sequencing of single micronuclei from these cells showed that mis-segregating chromosomes frequently also preferentially become entrapped in micronuclei. A similar bias was found in naturally occurring micronuclei of two cancer cell lines. We find that segregation error frequencies of individual chromosomes correlate with their location in the interphase nucleus, and show that this is highest for peripheral chromosomes behind spindle poles. Randomization of chromosome positions, Cas9-mediated live tracking and forced repositioning of individual chromosomes showed that a greater distance from the nuclear centre directly increases the propensity to mis-segregate. Accordingly, chromothripsis in cancer genomes9 and aneuploidies in early development10 occur more frequently for larger chromosomes, which are preferentially located near the nuclear periphery. Our findings reveal a direct link between nuclear chromosome positions, segregation error frequencies and micronucleus content, with implications for our understanding of tumour genome evolution and the origins of specific aneuploidies during development.
    DOI:  https://doi.org/10.1038/s41586-022-04938-0
  10. Trends Biochem Sci. 2022 Jul 11. pii: S0968-0004(22)00148-7. [Epub ahead of print]
    Coordinating gene expression during the cell cycle.
    Martin Fischer, Amy E Schade, Timothy B Branigan, Gerd A Müller, James A DeCaprio.
      Cell cycle-dependent gene transcription is tightly controlled by the retinoblastoma (RB):E2F and DREAM complexes, which repress all cell cycle genes during quiescence. Cyclin-dependent kinase (CDK) phosphorylation of RB and DREAM allows for the expression of two gene sets. The first set of genes, with peak expression in G1/S, is activated by E2F transcription factors (TFs) and is required for DNA synthesis. The second set, with maximum expression during G2/M, is required for mitosis and is coordinated by the MuvB complex, together with B-MYB and Forkhead box M1 (FOXM1). In this review, we summarize the key findings that established the distinct control mechanisms regulating G1/S and G2/M gene expression in mammals and discuss recent advances in the understanding of the temporal control of these genes.
    Keywords:  B-MYB; DREAM complex; FOXM1; MuvB complex; RB:E2F complex; transcription factors
    DOI:  https://doi.org/10.1016/j.tibs.2022.06.007
  11. Exp Hematol Oncol. 2022 Jul 13. 11(1): 40
    A sumoylation program is essential for maintaining the mitotic fidelity in proliferating mantle cell lymphoma cells.
    Walter Hanel, Pushpa Lata, Youssef Youssef, Ha Tran, Liudmyla Tsyba, Lalit Sehgal, Bradley W Blaser, Dennis Huszar, JoBeth Helmig-Mason, Liwen Zhang, Morgan S Schrock, Matthew K Summers, Wing Keung Chan, Alexander Prouty, Bethany L Mundy-Bosse, Selina Chen-Kiang, Alexey V Danilov, Kami Maddocks, Robert A Baiocchi, Lapo Alinari.
       BACKGROUND: Mantle cell lymphoma (MCL) is a rare, highly heterogeneous type of B-cell non-Hodgkin's lymphoma. The sumoylation pathway is known to be upregulated in many cancers including lymphoid malignancies. However, little is known about its oncogenic role in MCL.
    METHODS: Levels of sumoylation enzymes and sumoylated proteins were quantified in MCL cell lines and primary MCL patient samples by scRNA sequencing and immunoblotting. The sumoylation enzyme SAE2 was genetically and pharmacologically targeted with shRNA and TAK-981 (subasumstat). The effects of SAE2 inhibition on MCL proliferation and cell cycle were evaluated using confocal microscopy, live-cell microscopy, and flow cytometry. Immunoprecipitation and orbitrap mass spectrometry were used to identify proteins targeted by sumoylation in MCL cells.
    RESULTS: MCL cells have significant upregulation of the sumoylation pathway at the level of the enzymes SAE1 and SAE2 which correlated with poor prognosis and induction of mitosis associated genes. Selective inhibition of SAE2 with TAK-981 results in significant MCL cell death in vitro and in vivo with mitotic dysregulation being an important mechanism of action. We uncovered a sumoylation program in mitotic MCL cells comprised of multiple pathways which could be directly targeted with TAK-981. Centromeric localization of topoisomerase 2A, a gene highly upregulated in SAE1 and SAE2 overexpressing MCL cells, was lost with TAK-981 treatment likely contributing to the mitotic dysregulation seen in MCL cells.
    CONCLUSIONS: This study not only validates SAE2 as a therapeutic target in MCL but also opens the door to further mechanistic work to uncover how to best use desumoylation therapy to treat MCL and other lymphoid malignancies.
    Keywords:  SAE1; SAE2; TOP2A; Topoisomerase; UBA2; UBC9; UBE2I
    DOI:  https://doi.org/10.1186/s40164-022-00293-y
  12. Dev Cell. 2022 Jul 05. pii: S1534-5807(22)00448-8. [Epub ahead of print]
    A ROS-dependent mechanism promotes CDK2 phosphorylation to drive progression through S phase.
    Dilyana Georgieva Kirova, Kristyna Judasova, Julia Vorhauser, Thomas Zerjatke, Jacky Kieran Leung, Ingmar Glauche, Jörg Mansfeld.
      Reactive oxygen species (ROS) at the right concentration promote cell proliferation in cell culture, stem cells, and model organisms. However, the mystery of how ROS signaling is coordinated with cell cycle progression and integrated into the cell cycle control machinery on the molecular level remains unsolved. Here, we report increasing levels of mitochondrial ROS during the cell cycle in human cell lines that target cyclin-dependent kinase 2 (CDK2). Chemical and metabolic interferences with ROS production decrease T-loop phosphorylation on CDK2 and so impede its full activation and thus its efficient DNA replication. ROS regulate CDK2 activity through the oxidation of a conserved cysteine residue near the T-loop, which prevents the binding of the T-loop phosphatase KAP. Together, our data reveal how mitochondrial metabolism is coupled with DNA replication and cell cycle progression via ROS, thereby demonstrating how KAP activity toward CDKs can be cell cycle regulated.
    Keywords:  CDK2; DNA replication; KAP; T-loop phosphorylation; cell cycle; cyclin-dependent kinase; metabolism; mitochondria; proliferation; reactive oxygen species
    DOI:  https://doi.org/10.1016/j.devcel.2022.06.008
  13. Development. 2022 Jul 11. pii: dev.200613. [Epub ahead of print]
    Human neural progenitors establish a diffusion barrier in the ER membrane during cell division.
    Muhammad Khadeesh Bin Imtiaz, Lars N Royall, Daniel Gonzalez-Bohorquez, Sebastian Jessberger.
      Asymmetric segregation of cellular components regulates the fate and behavior of somatic stem cells. Similar to dividing budding yeast and precursor cells in C. elegans, it has been shown that mouse neural progenitors establish a diffusion barrier in the membrane of the endoplasmic reticulum (ER), which has been associated with asymmetric partitioning of damaged proteins and cellular age. However, the existence of an ER-diffusion barrier in human cells remains unknown. Here we used fluorescence loss in photobleaching (FLIP) imaging to show that human embryonic stem cell (hESC)- and induced pluripotent stem cell (iPSC)-derived neural progenitor cells establish an ER-diffusion barrier during cell division. The human ER-diffusion barrier is regulated via Lamin-dependent mechanisms and is associated with asymmetric segregation of mono- and polyubiquitinated, damaged proteins. Further, forebrain regionalized organoids derived from hESCs were used to show the establishment of an ER-membrane diffusion barrier in more naturalistic tissues mimicking early steps of human brain development. Thus, the data provided here show that human neural progenitors establish a diffusion barrier during cell division in the membrane of the ER, which may allow for asymmetric segregation of cellular components, contributing to the fate and behavior of human neural progenitor cells.
    Keywords:  Cell division; Diffusion barrier; ER membrane; Human neural progenitor; Neurogenesis
    DOI:  https://doi.org/10.1242/dev.200613
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