1
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La Torre M, Burla R, Saggio I. Preserving Genome Integrity: Unveiling the Roles of ESCRT Machinery. Cells 2024; 13:1307. [PMID: 39120335 PMCID: PMC11311930 DOI: 10.3390/cells13151307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Revised: 08/02/2024] [Accepted: 08/02/2024] [Indexed: 08/10/2024] Open
Abstract
The endosomal sorting complex required for transport (ESCRT) machinery is composed of an articulated architecture of proteins that assemble at multiple cellular sites. The ESCRT machinery is involved in pathways that are pivotal for the physiology of the cell, including vesicle transport, cell division, and membrane repair. The subunits of the ESCRT I complex are mainly responsible for anchoring the machinery to the action site. The ESCRT II subunits function to bridge and recruit the ESCRT III subunits. The latter are responsible for finalizing operations that, independently of the action site, involve the repair and fusion of membrane edges. In this review, we report on the data related to the activity of the ESCRT machinery at two sites: the nuclear membrane and the midbody and the bridge linking cells in the final stages of cytokinesis. In these contexts, the machinery plays a significant role for the protection of genome integrity by contributing to the control of the abscission checkpoint and to nuclear envelope reorganization and correlated resilience. Consistently, several studies show how the dysfunction of the ESCRT machinery causes genome damage and is a codriver of pathologies, such as laminopathies and cancer.
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Affiliation(s)
- Mattia La Torre
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, 00185 Rome, Italy; (M.L.T.); (R.B.)
| | - Romina Burla
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, 00185 Rome, Italy; (M.L.T.); (R.B.)
- CNR Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Isabella Saggio
- Department of Biology and Biotechnologies “Charles Darwin”, Sapienza University, 00185 Rome, Italy; (M.L.T.); (R.B.)
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2
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Richard A, Berthelet J, Judith D, Advedissian T, Espadas J, Jannot G, Amo A, Loew D, Lombard B, Casanova AG, Reynoird N, Roux A, Berlioz-Torrent C, Echard A, Weitzman JB, Medjkane S. Methylation of ESCRT-III components regulates the timing of cytokinetic abscission. Nat Commun 2024; 15:4023. [PMID: 38740816 PMCID: PMC11091153 DOI: 10.1038/s41467-024-47717-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 04/10/2024] [Indexed: 05/16/2024] Open
Abstract
Abscission is the final stage of cytokinesis, which cleaves the intercellular bridge (ICB) connecting two daughter cells. Abscission requires tight control of the recruitment and polymerization of the Endosomal Protein Complex Required for Transport-III (ESCRT-III) components. We explore the role of post-translational modifications in regulating ESCRT dynamics. We discover that SMYD2 methylates the lysine 6 residue of human CHMP2B, a key ESCRT-III component, at the ICB, impacting the dynamic relocation of CHMP2B to sites of abscission. SMYD2 loss-of-function (genetically or pharmacologically) causes CHMP2B hypomethylation, delayed CHMP2B polymerization and delayed abscission. This is phenocopied by CHMP2B lysine 6 mutants that cannot be methylated. Conversely, SMYD2 gain-of-function causes CHMP2B hypermethylation and accelerated abscission, specifically in cells undergoing cytokinetic challenges, thereby bypassing the abscission checkpoint. Additional experiments highlight the importance of CHMP2B methylation beyond cytokinesis, namely during ESCRT-III-mediated HIV-1 budding. We propose that lysine methylation signaling fine-tunes the ESCRT-III machinery to regulate the timing of cytokinetic abscission and other ESCRT-III dependent functions.
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Affiliation(s)
- Aurélie Richard
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France
| | - Jérémy Berthelet
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France
| | - Delphine Judith
- Université Paris Cité, Inserm, CNRS, Institut Cochin, F-75014, Paris, France
| | - Tamara Advedissian
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 Rue du Dr Roux, F-75015, Paris, France
| | - Javier Espadas
- Department of Biochemistry, University of Geneva, CH-1211, Geneva, Switzerland
| | - Guillaume Jannot
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France
| | - Angélique Amo
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry Proteomics, F-75005, Paris, France
| | - Berangere Lombard
- Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry Proteomics, F-75005, Paris, France
| | - Alexandre G Casanova
- Université Grenoble Alpes, CNRS UMR5309, INSERM U1209, Institute for Advanced Biosciences, 38000, Grenoble, France
| | - Nicolas Reynoird
- Université Grenoble Alpes, CNRS UMR5309, INSERM U1209, Institute for Advanced Biosciences, 38000, Grenoble, France
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, CH-1211, Geneva, Switzerland
| | | | - Arnaud Echard
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 Rue du Dr Roux, F-75015, Paris, France
| | - Jonathan B Weitzman
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France
| | - Souhila Medjkane
- Université Paris Cité, CNRS, UMR7126 Epigenetics and Cell Fate, F-75013, Paris, France.
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3
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Advedissian T, Frémont S, Echard A. Cytokinetic abscission requires actin-dependent microtubule severing. Nat Commun 2024; 15:1949. [PMID: 38431632 PMCID: PMC10908825 DOI: 10.1038/s41467-024-46062-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
Cell division is completed by the abscission of the intercellular bridge connecting the daughter cells. Abscission requires the polymerization of an ESCRT-III cone close to the midbody to both recruit the microtubule severing enzyme spastin and scission the plasma membrane. Here, we found that the microtubule and the membrane cuts are two separate events that are regulated differently. Using HeLa cells, we uncovered that the F-actin disassembling protein Cofilin-1 controls the disappearance of a transient pool of branched F-actin which is precisely assembled at the tip of the ESCRT-III cone shortly before the microtubule cut. Functionally, Cofilin-1 and Arp2/3-mediated branched F-actin favor abscission by promoting local severing of the microtubules but do not participate later in the membrane scission event. Mechanistically, we propose that branched F-actin functions as a physical barrier that limits ESCRT-III cone elongation and thereby favors stable spastin recruitment. Our work thus reveals that F-actin controls the timely and local disassembly of microtubules required for cytokinetic abscission.
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Affiliation(s)
- Tamara Advedissian
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Stéphane Frémont
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Arnaud Echard
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France.
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4
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Paine EL, Skalicky JJ, Whitby FG, Mackay DR, Ullman KS, Hill CP, Sundquist WI. The Calpain-7 protease functions together with the ESCRT-III protein IST1 within the midbody to regulate the timing and completion of abscission. eLife 2023; 12:e84515. [PMID: 37772788 PMCID: PMC10586806 DOI: 10.7554/elife.84515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 09/28/2023] [Indexed: 09/30/2023] Open
Abstract
The Endosomal Sorting Complexes Required for Transport (ESCRT) machinery mediates the membrane fission step that completes cytokinetic abscission and separates dividing cells. Filaments composed of ESCRT-III subunits constrict membranes of the intercellular bridge midbody to the abscission point. These filaments also bind and recruit cofactors whose activities help execute abscission and/or delay abscission timing in response to mitotic errors via the NoCut/Abscission checkpoint. We previously showed that the ESCRT-III subunit IST1 binds the cysteine protease Calpain-7 (CAPN7) and that CAPN7 is required for both efficient abscission and NoCut checkpoint maintenance (Wenzel et al., 2022). Here, we report biochemical and crystallographic studies showing that the tandem microtubule-interacting and trafficking (MIT) domains of CAPN7 bind simultaneously to two distinct IST1 MIT interaction motifs. Structure-guided point mutations in either CAPN7 MIT domain disrupted IST1 binding in vitro and in cells, and depletion/rescue experiments showed that the CAPN7-IST1 interaction is required for (1) CAPN7 recruitment to midbodies, (2) efficient abscission, and (3) NoCut checkpoint arrest. CAPN7 proteolytic activity is also required for abscission and checkpoint maintenance. Hence, IST1 recruits CAPN7 to midbodies, where its proteolytic activity is required to regulate and complete abscission.
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Affiliation(s)
- Elliott L Paine
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Frank G Whitby
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Douglas R Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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5
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Elias RD, Zhu Y, Su Q, Ghirlando R, Zhang J, Deshmukh L. Reversible phase separation of ESCRT protein ALIX through tyrosine phosphorylation. SCIENCE ADVANCES 2023; 9:eadg3913. [PMID: 37450591 PMCID: PMC10348681 DOI: 10.1126/sciadv.adg3913] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 06/14/2023] [Indexed: 07/18/2023]
Abstract
Cytokinetic abscission, the last step of cell division, is regulated by the ESCRT machinery. In response to mitotic errors, ESCRT proteins, namely, ALIX, CHMP4B, and CHMP4C, accumulate in the cytosolic compartments termed "abscission checkpoint bodies" (ACBs) to delay abscission and prevent tumorigenesis. ALIX contributes to the biogenesis and stability of ACBs via an unknown mechanism. We show that ALIX phase separates into nondynamic condensates in vitro and in vivo, mediated by the amyloidogenic portion of its proline-rich domain. ALIX condensates confined CHMP4 paralogs in vitro. These condensates dissolved and reformed upon reversible tyrosine phosphorylation of ALIX, mediated by Src kinase and PTP1B, and sequestration of CHMP4C altered their Src-mediated dissolution. NMR analysis revealed how ALIX triggers the activation of CHMP4 proteins, which is required for successful abscission. These results implicate ALIX's phase separation in the modulation of ACBs. This study also highlights how posttranslational modifications can control protein phase separation.
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Affiliation(s)
- Ruben D. Elias
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yingqi Zhu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qi Su
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jin Zhang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lalit Deshmukh
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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6
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González B, Aldea M, Cullen PJ. Chaperone-Dependent Degradation of Cdc42 Promotes Cell Polarity and Shields the Protein from Aggregation. Mol Cell Biol 2023; 43:200-222. [PMID: 37114947 PMCID: PMC10184603 DOI: 10.1080/10985549.2023.2198171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 04/29/2023] Open
Abstract
Rho GTPases are global regulators of cell polarity and signaling. By exploring the turnover regulation of the yeast Rho GTPase Cdc42p, we identified new regulatory features surrounding the stability of the protein. We specifically show that Cdc42p is degraded at 37 °C by chaperones through lysine residues located in the C-terminus of the protein. Cdc42p turnover at 37 °C occurred by the 26S proteasome in an ESCRT-dependent manner in the lysosome/vacuole. By analyzing versions of Cdc42p that were defective for turnover, we show that turnover at 37 °C promoted cell polarity but was defective for sensitivity to mating pheromone, presumably mediated through a Cdc42p-dependent MAP kinase pathway. We also identified one residue (K16) in the P-loop of the protein that was critical for Cdc42p stability. Accumulation of Cdc42pK16R in some contexts led to the formation of protein aggregates, which were enriched in aging mother cells and cells undergoing proteostatic stress. Our study uncovers new aspects of protein turnover regulation of a Rho-type GTPase that may extend to other systems. Moreover, residues identified here that mediate Cdc42p turnover correlate with several human diseases, which may suggest that turnover regulation of Cdc42p is important to aspects of human health.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
| | - Martí Aldea
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona, Spain
| | - Paul J. Cullen
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
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7
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Andrade V, Echard A. Mechanics and regulation of cytokinetic abscission. Front Cell Dev Biol 2022; 10:1046617. [PMID: 36506096 PMCID: PMC9730121 DOI: 10.3389/fcell.2022.1046617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/31/2022] [Indexed: 11/25/2022] Open
Abstract
Cytokinetic abscission leads to the physical cut of the intercellular bridge (ICB) connecting the daughter cells and concludes cell division. In different animal cells, it is well established that the ESCRT-III machinery is responsible for the constriction and scission of the ICB. Here, we review the mechanical context of abscission. We first summarize the evidence that the ICB is initially under high tension and explain why, paradoxically, this can inhibit abscission in epithelial cells by impacting on ESCRT-III assembly. We next detail the different mechanisms that have been recently identified to release ICB tension and trigger abscission. Finally, we discuss whether traction-induced mechanical cell rupture could represent an ancient alternative mechanism of abscission and suggest future research avenues to further understand the role of mechanics in regulating abscission.
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Affiliation(s)
- Virginia Andrade
- CNRS UMR3691, Membrane Traffic and Cell Division Unit, Institut Pasteur, Université Paris Cité, Paris, France,Collège Doctoral, Sorbonne Université, Paris, France
| | - Arnaud Echard
- CNRS UMR3691, Membrane Traffic and Cell Division Unit, Institut Pasteur, Université Paris Cité, Paris, France,*Correspondence: Arnaud Echard,
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8
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Wenzel DM, Mackay DR, Skalicky JJ, Paine EL, Miller MS, Ullman KS, Sundquist WI. Comprehensive analysis of the human ESCRT-III-MIT domain interactome reveals new cofactors for cytokinetic abscission. eLife 2022; 11:e77779. [PMID: 36107470 PMCID: PMC9477494 DOI: 10.7554/elife.77779] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
The 12 related human ESCRT-III proteins form filaments that constrict membranes and mediate fission, including during cytokinetic abscission. The C-terminal tails of polymerized ESCRT-III subunits also bind proteins that contain Microtubule-Interacting and Trafficking (MIT) domains. MIT domains can interact with ESCRT-III tails in many different ways to create a complex binding code that is used to recruit essential cofactors to sites of ESCRT activity. Here, we have comprehensively and quantitatively mapped the interactions between all known ESCRT-III tails and 19 recombinant human MIT domains. We measured 228 pairwise interactions, quantified 60 positive interactions, and discovered 18 previously unreported interactions. We also report the crystal structure of the SPASTIN MIT domain in complex with the IST1 C-terminal tail. Three MIT enzymes were studied in detail and shown to: (1) localize to cytokinetic midbody membrane bridges through interactions with their specific ESCRT-III binding partners (SPASTIN-IST1, KATNA1-CHMP3, and CAPN7-IST1), (2) function in abscission (SPASTIN, KATNA1, and CAPN7), and (3) function in the 'NoCut' abscission checkpoint (SPASTIN and CAPN7). Our studies define the human MIT-ESCRT-III interactome, identify new factors and activities required for cytokinetic abscission and its regulation, and provide a platform for analyzing ESCRT-III and MIT cofactor interactions in all ESCRT-mediated processes.
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Affiliation(s)
- Dawn M Wenzel
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Douglas R Mackay
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Jack J Skalicky
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Elliott L Paine
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Matthew S Miller
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of UtahSalt Lake CityUnited States
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of MedicineSalt Lake CityUnited States
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Andrade V, Bai J, Gupta-Rossi N, Jimenez AJ, Delevoye C, Lamaze C, Echard A. Caveolae promote successful abscission by controlling intercellular bridge tension during cytokinesis. SCIENCE ADVANCES 2022; 8:eabm5095. [PMID: 35417244 PMCID: PMC9007517 DOI: 10.1126/sciadv.abm5095] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
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.
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Affiliation(s)
- Virginia Andrade
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015 Paris, France
- Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Jian Bai
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015 Paris, France
- Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Neetu Gupta-Rossi
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015 Paris, France
| | - Ana Joaquina Jimenez
- Dynamics of Intracellular Organization Laboratory, Institut Curie, PSL Research University, CNRS UMR 144, Sorbonne Université, 75005 Paris, France
| | - Cédric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR144, Structure and Membrane Compartments, 75005 Paris, France
- Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), 75005 Paris, France
| | - Christophe Lamaze
- Institut Curie, PSL Research University, INSERM U1143, CNRS UMR 3666, Membrane Mechanics and Dynamics of Intracellular Signaling Laboratory, 26 rue d’Ulm, 75005 Paris, France
| | - Arnaud Echard
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015 Paris, France
- Corresponding author.
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10
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Incomplete abscission and cytoplasmic bridges in the evolution of eukaryotic multicellularity. Curr Biol 2022; 32:R385-R397. [DOI: 10.1016/j.cub.2022.03.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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11
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The Abscission Checkpoint: A Guardian of Chromosomal Stability. Cells 2021; 10:cells10123350. [PMID: 34943860 PMCID: PMC8699595 DOI: 10.3390/cells10123350] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 12/11/2022] Open
Abstract
The abscission checkpoint contributes to the fidelity of chromosome segregation by delaying completion of cytokinesis (abscission) when there is chromatin lagging in the intercellular bridge between dividing cells. Although additional triggers of an abscission checkpoint-delay have been described, including nuclear pore defects, replication stress or high intercellular bridge tension, this review will focus only on chromatin bridges. In the presence of such abnormal chromosomal tethers in mammalian cells, the abscission checkpoint requires proper localization and optimal kinase activity of the Chromosomal Passenger Complex (CPC)-catalytic subunit Aurora B at the midbody and culminates in the inhibition of Endosomal Sorting Complex Required for Transport-III (ESCRT-III) components at the abscission site to delay the final cut. Furthermore, cells with an active checkpoint stabilize the narrow cytoplasmic canal that connects the two daughter cells until the chromatin bridges are resolved. Unsuccessful resolution of chromatin bridges in checkpoint-deficient cells or in cells with unstable intercellular canals can lead to chromatin bridge breakage or tetraploidization by regression of the cleavage furrow. In turn, these outcomes can lead to accumulation of DNA damage, chromothripsis, generation of hypermutation clusters and chromosomal instability, which are associated with cancer formation or progression. Recently, many important questions regarding the mechanisms of the abscission checkpoint have been investigated, such as how the presence of chromatin bridges is signaled to the CPC, how Aurora B localization and kinase activity is regulated in late midbodies, the signaling pathways by which Aurora B implements the abscission delay, and how the actin cytoskeleton is remodeled to stabilize intercellular canals with DNA bridges. Here, we review recent progress toward understanding the mechanisms of the abscission checkpoint and its role in guarding genome integrity at the chromosome level, and consider its potential implications for cancer therapy.
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