1
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Bement WM, Goryachev AB, Miller AL, von Dassow G. Patterning of the cell cortex by Rho GTPases. Nat Rev Mol Cell Biol 2024; 25:290-308. [PMID: 38172611 DOI: 10.1038/s41580-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2023] [Indexed: 01/05/2024]
Abstract
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
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Affiliation(s)
- William M Bement
- Center for Quantitative Cell Imaging, Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Andrew B Goryachev
- Center for Engineering Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Ann L Miller
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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2
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di Pietro F, Osswald M, De Las Heras JM, Cristo I, López-Gay J, Wang Z, Pelletier S, Gaugué I, Leroy A, Martin C, Morais-de-Sá E, Bellaïche Y. Systematic analysis of RhoGEF/GAP localizations uncovers regulators of mechanosensing and junction formation during epithelial cell division. Curr Biol 2023; 33:858-874.e7. [PMID: 36917931 PMCID: PMC10017266 DOI: 10.1016/j.cub.2023.01.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/30/2022] [Accepted: 01/16/2023] [Indexed: 02/17/2023]
Abstract
Cell proliferation is central to epithelial tissue development, repair, and homeostasis. During cell division, small RhoGTPases control both actomyosin dynamics and cell-cell junction remodeling to faithfully segregate the genome while maintaining tissue polarity and integrity. To decipher the mechanisms of RhoGTPase spatiotemporal regulation during epithelial cell division, we generated a transgenic fluorescently tagged library for the 48 Drosophila Rho guanine exchange factors (RhoGEFs) and GTPase-activating proteins (GAPs), and we systematically characterized their endogenous distributions by time-lapse microscopy. Therefore, we unveiled candidate regulators of the interplay between actomyosin and junctional dynamics during epithelial cell division. Building on these findings, we established that the conserved RhoGEF Cysts and RhoGEF4 play sequential and distinct roles to couple cytokinesis with de novo junction formation. During ring contraction, Cysts via Rho1 participates in the neighbor mechanosensing response, promoting daughter-daughter cell membrane juxtaposition in preparation to de novo junction formation. Subsequently and upon midbody formation, RhoGEF4 via Rac acts in the dividing cell to ensure the withdrawal of the neighboring cell membranes, thus controlling de novo junction length and cell-cell arrangements upon cytokinesis. Altogether, our findings delineate how the RhoGTPases Rho and Rac are locally and temporally activated during epithelial cytokinesis, highlighting the RhoGEF/GAP library as a key resource to understand the broad range of biological processes regulated by RhoGTPases.
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Affiliation(s)
- Florencia di Pietro
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Mariana Osswald
- IBMC - Instituto de Biologia Molecular e Celular; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - José M De Las Heras
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Inês Cristo
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Jesús López-Gay
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Zhimin Wang
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Stéphane Pelletier
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Isabelle Gaugué
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Adrien Leroy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Charlotte Martin
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Eurico Morais-de-Sá
- IBMC - Instituto de Biologia Molecular e Celular; i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
| | - Yohanns Bellaïche
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France.
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3
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Zhang P, Chen J, Wang X, Geng Y, Sun L, Zhang H. The centralspindlin complex regulates cytokinesis and morphogenesis in the C. elegans spermatheca. Development 2023; 150:286720. [PMID: 36661358 DOI: 10.1242/dev.200840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 12/13/2022] [Indexed: 01/21/2023]
Abstract
Organ morphogenesis needs orchestration of a series of cellular events, including cell division, cell shape change, cell rearrangement and cell death. Cytokinesis, the final step of cell division, is involved in the control of organ size, shape and function. Mechanistically, it is unclear how the molecules involved in cytokinesis regulate organ size and shape. Here, we demonstrate that the centralspindlin complex coordinates cell division and epithelial morphogenesis by regulating cytokinesis. Loss of the centralspindlin components CYK-4 and ZEN-4 disrupts cell division, resulting in altered cell arrangement and malformation of the Caenorhabditis elegans spermatheca. Further investigation revealed that most spermathecal cells undergo nuclear division without completion of cytokinesis. Germline mutant-based analyses suggest that CYK-4 regulates cytokinesis of spermathecal cells in a GTPase activator activity-independent manner. Spermathecal morphology defects can be enhanced by double knockdown of rho-1 and cyk-4, and partially suppressed by double knockdown of cdc-42 and cyk-4. Thus, the centralspindlin components CYK-4 and ZEN-4, together with RHO-1 and CDC-42, are central players of a signaling network that guides spermathecal morphogenesis by enabling completion of cytokinesis.
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Affiliation(s)
- Pei Zhang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Jiwei Chen
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Xiangchuan Wang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Yingchao Geng
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Liangyu Sun
- Biological Imaging and Stem Cell Core, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Hongjie Zhang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Taipa, Macau SAR 999078, China
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4
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Ozugergin I, Piekny A. Diversity is the spice of life: An overview of how cytokinesis regulation varies with cell type. Front Cell Dev Biol 2022; 10:1007614. [PMID: 36420142 PMCID: PMC9676254 DOI: 10.3389/fcell.2022.1007614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/24/2022] [Indexed: 09/01/2023] Open
Abstract
Cytokinesis is required to physically cleave a cell into two daughters at the end of mitosis. Decades of research have led to a comprehensive understanding of the core cytokinesis machinery and how it is regulated in animal cells, however this knowledge was generated using single cells cultured in vitro, or in early embryos before tissues develop. This raises the question of how cytokinesis is regulated in diverse animal cell types and developmental contexts. Recent studies of distinct cell types in the same organism or in similar cell types from different organisms have revealed striking differences in how cytokinesis is regulated, which includes different threshold requirements for the structural components and the mechanisms that regulate them. In this review, we highlight these differences with an emphasis on pathways that are independent of the mitotic spindle, and operate through signals associated with the cortex, kinetochores, or chromatin.
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Affiliation(s)
- Imge Ozugergin
- Department of Biology, McGill University, Montreal, QC, Canada
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada
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5
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Sana S, Rajeevan A, Kotak S. Membrane compartmentalization of Ect2/Cyk4/Mklp1 and NuMA/dynein regulates cleavage furrow formation. J Biophys Biochem Cytol 2022; 221:213522. [PMID: 36197340 PMCID: PMC9539458 DOI: 10.1083/jcb.202203127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/09/2022] [Accepted: 09/02/2022] [Indexed: 12/13/2022] Open
Abstract
In animal cells, spindle elongation during anaphase is temporally coupled with cleavage furrow formation. Spindle elongation during anaphase is regulated by NuMA/dynein/dynactin complexes that occupy the polar region of the cell membrane and are excluded from the equatorial membrane. How NuMA/dynein/dynactin are excluded from the equatorial membrane and the biological significance of this exclusion remains unknown. Here, we show that the centralspindlin (Cyk4/Mklp1) and its interacting partner RhoGEF Ect2 are required for NuMA/dynein/dynactin exclusion from the equatorial cell membrane. The Ect2-based (Ect2/Cyk4/Mklp1) and NuMA-based (NuMA/dynein/dynactin) complexes occupy mutually exclusive membrane surfaces during anaphase. The equatorial membrane enrichment of Ect2-based complexes is essential for NuMA/dynein/dynactin exclusion and proper spindle elongation. Conversely, NuMA-based complexes at the polar region of the cell membrane ensure spatially confined localization of Ect2-based complexes and thus RhoA. Overall, our work establishes that membrane compartmentalization of NuMA-based and Ect2-based complexes at the two distinct cell surfaces restricts dynein/dynactin and RhoA for coordinating spindle elongation with cleavage furrow formation.
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Affiliation(s)
- Shrividya Sana
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore, India
| | - Ashwathi Rajeevan
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore, India
| | - Sachin Kotak
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore, India,Correspondence to Sachin Kotak:
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6
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Koh SP, Pham NP, Piekny A. Seeing is believing: tools to study the role of Rho GTPases during cytokinesis. Small GTPases 2022; 13:211-224. [PMID: 34405757 PMCID: PMC9707540 DOI: 10.1080/21541248.2021.1957384] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cytokinesis is required to cleave the daughter cells at the end of mitosis and relies on the spatiotemporal control of RhoA GTPase. Cytokinesis failure can lead to changes in cell fate or aneuploidy, which can be detrimental during development and/or can lead to cancer. However, our knowledge of the pathways that regulate RhoA during cytokinesis is limited, and the role of other Rho family GTPases is not clear. This is largely because the study of Rho GTPases presents unique challenges using traditional cell biological and biochemical methods, and they have pleiotropic functions making genetic studies difficult to interpret. The recent generation of optogenetic tools and biosensors that control and detect active Rho has overcome some of these challenges and is helping to elucidate the role of RhoA in cytokinesis. However, improvements are needed to reveal the role of other Rho GTPases in cytokinesis, and to identify the molecular mechanisms that control Rho activity. This review examines some of the outstanding questions in cytokinesis, and explores tools for the imaging and control of Rho GTPases.
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Affiliation(s)
- Su Pin Koh
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Nhat Phi Pham
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada,CONTACT Alisa Piekny Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
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7
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Longhini KM, Glotzer M. Aurora A and cortical flows promote polarization and cytokinesis by inducing asymmetric ECT-2 accumulation. eLife 2022; 11:83992. [PMID: 36533896 PMCID: PMC9799973 DOI: 10.7554/elife.83992] [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: 10/06/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
In the early Caenorhabditis elegans embryo, cell polarization and cytokinesis are interrelated yet distinct processes. Here, we sought to understand a poorly understood aspect of cleavage furrow positioning. Early C. elegans embryos deficient in the cytokinetic regulator centralspindlin form furrows, due to an inhibitory activity that depends on aster positioning relative to the polar cortices. Here, we show polar relaxation is associated with depletion of cortical ECT-2, a RhoGEF, specifically at the posterior cortex. Asymmetric ECT-2 accumulation requires intact centrosomes, Aurora A (AIR-1), and myosin-dependent cortical flows. Within a localization competent ECT-2 fragment, we identified three putative phospho-acceptor sites in the PH domain of ECT-2 that render ECT-2 responsive to inhibition by AIR-1. During both polarization and cytokinesis, our results suggest that centrosomal AIR-1 breaks symmetry via ECT-2 phosphorylation; this local inhibition of ECT-2 is amplified by myosin-driven flows that generate regional ECT-2 asymmetry. Together, these mechanisms cooperate to induce polarized assembly of cortical myosin, contributing to both embryo polarization and cytokinesis.
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Affiliation(s)
- Katrina M Longhini
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicagoUnited States
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicagoUnited States
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8
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From primordial germ cells to spermatids in Caenorhabditis elegans. Semin Cell Dev Biol 2021; 127:110-120. [PMID: 34930663 DOI: 10.1016/j.semcdb.2021.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/17/2021] [Accepted: 12/07/2021] [Indexed: 12/24/2022]
Abstract
Development of a syncytial germline for gamete formation requires complex regulation of cytokinesis and cytoplasmic remodeling. Recently, several uncovered cellular events have been investigated in the Caenorhabditis elegans (C. elegans) germline. In these cellular processes, the factors involved in contractility are highly conserved with those of mitosis and meiosis. However, the underlying regulatory mechanisms are far more complicated than previously thought, likely due to the single syncytial germline structure. In this review, we highlight how the proteins involved in contractility ensure faithful cell division in different cellular contexts and how they contribute to maintaining intercellular bridge stability. In addition, we discuss the current understanding of the cellular events of cytokinesis and cytoplasmic remodeling during the development of the C. elegans germline, including progenitor germ cells, germ cells, and spermatocytes. Comparisons are made with relevant systems in Drosophila melanogaster (D. melanogaster) and other animal models.
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9
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Chapa-Y-Lazo B, Hamanaka M, Wray A, Balasubramanian MK, Mishima M. Polar relaxation by dynein-mediated removal of cortical myosin II. J Cell Biol 2021; 219:151836. [PMID: 32497213 PMCID: PMC7401816 DOI: 10.1083/jcb.201903080] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 02/03/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Nearly six decades ago, Lewis Wolpert proposed the relaxation of the polar cell cortex by the radial arrays of astral microtubules as a mechanism for cleavage furrow induction. While this mechanism has remained controversial, recent work has provided evidence for polar relaxation by astral microtubules, although its molecular mechanisms remain elusive. Here, using C. elegans embryos, we show that polar relaxation is achieved through dynein-mediated removal of myosin II from the polar cortexes. Mutants that position centrosomes closer to the polar cortex accelerated furrow induction, whereas suppression of dynein activity delayed furrowing. We show that dynein-mediated removal of myosin II from the polar cortexes triggers a bidirectional cortical flow toward the cell equator, which induces the assembly of the actomyosin contractile ring. These results provide a molecular mechanism for the aster-dependent polar relaxation, which works in parallel with equatorial stimulation to promote robust cytokinesis.
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Affiliation(s)
- Bernardo Chapa-Y-Lazo
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
| | - Motonari Hamanaka
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK.,Hokkaido University, Sapporo, Japan
| | - Alexander Wray
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK.,University of Nottingham, Nottingham, UK
| | - Mohan K Balasubramanian
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
| | - Masanori Mishima
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
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10
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Pal D, Ellis A, Sepúlveda-Ramírez SP, Salgado T, Terrazas I, Reyes G, De La Rosa R, Henson JH, Shuster CB. Rac and Arp2/3-Nucleated Actin Networks Antagonize Rho During Mitotic and Meiotic Cleavages. Front Cell Dev Biol 2020; 8:591141. [PMID: 33282870 PMCID: PMC7705106 DOI: 10.3389/fcell.2020.591141] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/20/2020] [Indexed: 12/01/2022] Open
Abstract
In motile cells, the activities of the different Rho family GTPases are spatially segregated within the cell, and during cytokinesis there is evidence that this may also be the case. But while Rho’s role as the central organizer for contractile ring assembly is well established, the role of Rac and the branched actin networks it promotes is less well understood. To characterize the contributions of these proteins during cytokinesis, we manipulated Rac and Arp2/3 activity during mitosis and meiosis in sea urchin embryos and sea star oocytes. While neither Rac nor Arp2/3 were essential for early embryonic divisions, loss of either Rac or Arp2/3 activity resulted in polar body defects. Expression of activated Rac resulted in cytokinesis failure as early as the first division, and in oocytes, activated Rac suppressed both the Rho wave that traverses the oocyte prior to polar body extrusion as well as polar body formation itself. However, the inhibitory effect of Rac on cytokinesis, polar body formation and the Rho wave could be suppressed by effector-binding mutations or direct inhibition of Arp2/3. Together, these results suggest that Rac- and Arp2/3 mediated actin networks may directly antagonize Rho signaling, thus providing a potential mechanism to explain why Arp2/3-nucleated branched actin networks must be suppressed at the cell equator for successful cytokinesis.
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Affiliation(s)
- Debadrita Pal
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Andrea Ellis
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | | | - Torey Salgado
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Isabella Terrazas
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Gabriela Reyes
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - Richard De La Rosa
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
| | - John H Henson
- Department of Biology, Dickinson College, Carlisle, PA, United States
| | - Charles B Shuster
- Department of Biology, New Mexico State University, Las Cruces, NM, United States
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Carim SC, Kechad A, Hickson GRX. Animal Cell Cytokinesis: The Rho-Dependent Actomyosin-Anilloseptin Contractile Ring as a Membrane Microdomain Gathering, Compressing, and Sorting Machine. Front Cell Dev Biol 2020; 8:575226. [PMID: 33117802 PMCID: PMC7575755 DOI: 10.3389/fcell.2020.575226] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/07/2020] [Indexed: 12/19/2022] Open
Abstract
Cytokinesis is the last step of cell division that partitions the cellular organelles and cytoplasm of one cell into two. In animal cells, cytokinesis requires Rho-GTPase-dependent assembly of F-actin and myosin II (actomyosin) to form an equatorial contractile ring (CR) that bisects the cell. Despite 50 years of research, the precise mechanisms of CR assembly, tension generation and closure remain elusive. This hypothesis article considers a holistic view of the CR that, in addition to actomyosin, includes another Rho-dependent cytoskeletal sub-network containing the scaffold protein, Anillin, and septin filaments (collectively termed anillo-septin). We synthesize evidence from our prior work in Drosophila S2 cells that actomyosin and anillo-septin form separable networks that are independently anchored to the plasma membrane. This latter realization leads to a simple conceptual model in which CR assembly and closure depend upon the micro-management of the membrane microdomains to which actomyosin and anillo-septin sub-networks are attached. During CR assembly, actomyosin contractility gathers and compresses its underlying membrane microdomain attachment sites. These microdomains resist this compression, which builds tension. During CR closure, membrane microdomains are transferred from the actomyosin sub-network to the anillo-septin sub-network, with which they flow out of the CR as it advances. This relative outflow of membrane microdomains regulates tension, reduces the circumference of the CR and promotes actomyosin disassembly all at the same time. According to this hypothesis, the metazoan CR can be viewed as a membrane microdomain gathering, compressing and sorting machine that intrinsically buffers its own tension through coordination of actomyosin contractility and anillo-septin-membrane relative outflow, all controlled by Rho. Central to this model is the abandonment of the dogmatic view that the plasma membrane is always readily deformable by the underlying cytoskeleton. Rather, the membrane resists compression to build tension. The notion that the CR might generate tension through resistance to compression of its own membrane microdomain attachment sites, can account for numerous otherwise puzzling observations and warrants further investigation using multiple systems and methods.
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Affiliation(s)
- Sabrya C. Carim
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada
| | - Amel Kechad
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada
| | - Gilles R. X. Hickson
- CHU Sainte-Justine Research Center, Université de Montréal, Montréal, QC, Canada
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
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12
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Verma V, Mogilner A, Maresca TJ. Classical and Emerging Regulatory Mechanisms of Cytokinesis in Animal Cells. BIOLOGY 2019; 8:biology8030055. [PMID: 31357447 PMCID: PMC6784142 DOI: 10.3390/biology8030055] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/05/2019] [Accepted: 07/23/2019] [Indexed: 12/12/2022]
Abstract
The primary goal of cytokinesis is to produce two daughter cells, each having a full set of chromosomes. To achieve this, cells assemble a dynamic structure between segregated sister chromatids called the contractile ring, which is made up of filamentous actin, myosin-II, and other regulatory proteins. Constriction of the actomyosin ring generates a cleavage furrow that divides the cytoplasm to produce two daughter cells. Decades of research have identified key regulators and underlying molecular mechanisms; however, many fundamental questions remain unanswered and are still being actively investigated. This review summarizes the key findings, computational modeling, and recent advances in understanding of the molecular mechanisms that control the formation of the cleavage furrow and cytokinesis.
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Affiliation(s)
- Vikash Verma
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
- Department of Biology, New York University, New York, NY 10012, USA
| | - Thomas J Maresca
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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13
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Network Contractility During Cytokinesis-from Molecular to Global Views. Biomolecules 2019; 9:biom9050194. [PMID: 31109067 PMCID: PMC6572417 DOI: 10.3390/biom9050194] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 12/28/2022] Open
Abstract
Cytokinesis is the last stage of cell division, which partitions the mother cell into two daughter cells. It requires the assembly and constriction of a contractile ring that consists of a filamentous contractile network of actin and myosin. Network contractility depends on network architecture, level of connectivity and myosin motor activity, but how exactly is the contractile ring network organized or interconnected and how much it depends on motor activity remains unclear. Moreover, the contractile ring is not an isolated entity; rather, it is integrated into the surrounding cortex. Therefore, the mechanical properties of the cell cortex and cortical behaviors are expected to impact contractile ring functioning. Due to the complexity of the process, experimental approaches have been coupled to theoretical modeling in order to advance its global understanding. While earlier coarse-grained descriptions attempted to provide an integrated view of the process, recent models have mostly focused on understanding the behavior of an isolated contractile ring. Here we provide an overview of the organization and dynamics of the actomyosin network during cytokinesis and discuss existing theoretical models in light of cortical behaviors and experimental evidence from several systems. Our view on what is missing in current models and should be tested in the future is provided.
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14
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Pintard L, Bowerman B. Mitotic Cell Division in Caenorhabditis elegans. Genetics 2019; 211:35-73. [PMID: 30626640 PMCID: PMC6325691 DOI: 10.1534/genetics.118.301367] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/24/2018] [Indexed: 11/18/2022] Open
Abstract
Mitotic cell divisions increase cell number while faithfully distributing the replicated genome at each division. The Caenorhabditis elegans embryo is a powerful model for eukaryotic cell division. Nearly all of the genes that regulate cell division in C. elegans are conserved across metazoan species, including humans. The C. elegans pathways tend to be streamlined, facilitating dissection of the more redundant human pathways. Here, we summarize the virtues of C. elegans as a model system and review our current understanding of centriole duplication, the acquisition of pericentriolar material by centrioles to form centrosomes, the assembly of kinetochores and the mitotic spindle, chromosome segregation, and cytokinesis.
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Affiliation(s)
- Lionel Pintard
- Equipe labellisée Ligue contre le Cancer, Institut Jacques Monod, Team Cell Cycle and Development UMR7592, Centre National de la Recherche Scientifique - Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France
| | - Bruce Bowerman
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
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15
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Chan FY, Silva AM, Saramago J, Pereira-Sousa J, Brighton HE, Pereira M, Oegema K, Gassmann R, Carvalho AX. The ARP2/3 complex prevents excessive formin activity during cytokinesis. Mol Biol Cell 2018; 30:96-107. [PMID: 30403552 PMCID: PMC6337913 DOI: 10.1091/mbc.e18-07-0471] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cytokinesis completes cell division by constriction of an actomyosin contractile ring that separates the two daughter cells. Here we use the early Caenorhabditis elegans embryo to explore how the actin filament network in the ring and the surrounding cortex is regulated by the single cytokinesis formin CYK-1 and the ARP2/3 complex, which nucleate nonbranched and branched filaments, respectively. We show that CYK-1 and the ARP2/3 complex are the predominant F-actin nucleators responsible for generating distinct cortical F-actin architectures and that depletion of either nucleator affects the kinetics of cytokinesis. CYK-1 is critical for normal F-actin levels in the contractile ring, and acute inhibition of CYK-1 after furrow ingression slows ring constriction rate, suggesting that CYK-1 activity is required throughout ring constriction. Surprisingly, although the ARP2/3 complex does not localize in the contractile ring, depletion of the ARP2 subunit or treatment with ARP2/3 complex inhibitor delays contractile ring formation and constriction. We present evidence that the delays are due to an excess in formin-nucleated cortical F-actin, suggesting that the ARP2/3 complex negatively regulates CYK-1 activity. We conclude that the kinetics of cytokinesis are modulated by interplay between the two major actin filament nucleators.
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Affiliation(s)
- Fung-Yi Chan
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana M Silva
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Joana Saramago
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Joana Pereira-Sousa
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Hailey E Brighton
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California San Diego, La Jolla, CA 92093
| | - Marisa Pereira
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Karen Oegema
- Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California San Diego, La Jolla, CA 92093
| | - Reto Gassmann
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana Xavier Carvalho
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
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16
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Agarwal P, Zaidel-Bar R. Principles of Actomyosin Regulation In Vivo. Trends Cell Biol 2018; 29:150-163. [PMID: 30385150 DOI: 10.1016/j.tcb.2018.09.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/22/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022]
Abstract
The actomyosin cytoskeleton is responsible for most force-driven processes in cells and tissues. How it assembles into the necessary structures at the right time and place is an important question. Here, we focus on molecular mechanisms of actomyosin regulation recently elucidated in animal models, and highlight several common principles that emerge. The architecture of the actomyosin network - an important determinant of its function - results from actin polymerization, crosslinking and turnover, localized myosin activation, and contractility-driven self-organization. Spatiotemporal regulation is achieved by tissue-specific expression and subcellular localization of Rho GTPase regulators. Subcellular anchor points of actomyosin structures control the outcome of their contraction, and molecular feedback mechanisms dictate whether they are transient, cyclic, or persistent.
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Affiliation(s)
- Priti Agarwal
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, National University of Singapore, Singapore; Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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17
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Michaux JB, Robin FB, McFadden WM, Munro EM. Excitable RhoA dynamics drive pulsed contractions in the early C. elegans embryo. J Cell Biol 2018; 217:4230-4252. [PMID: 30275107 PMCID: PMC6279378 DOI: 10.1083/jcb.201806161] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/30/2018] [Accepted: 09/05/2018] [Indexed: 12/17/2022] Open
Abstract
Pulsed actomyosin contractility underlies many morphogenetic processes. Here, Michaux et al. show that, in early C. elegans embryos, pulsed contractions are generated by intrinsically excitable RhoA dynamics, involving fast autoactivation of RhoA and delayed negative feedback through local actin-dependent recruitment of the RhoGAPs RGA-3/4. Pulsed actomyosin contractility underlies diverse modes of tissue morphogenesis, but the underlying mechanisms remain poorly understood. Here, we combined quantitative imaging with genetic perturbations to identify a core mechanism for pulsed contractility in early Caenorhabditis elegans embryos. We show that pulsed accumulation of actomyosin is governed by local control of assembly and disassembly downstream of RhoA. Pulsed activation and inactivation of RhoA precede, respectively, the accumulation and disappearance of actomyosin and persist in the absence of Myosin II. We find that fast (likely indirect) autoactivation of RhoA drives pulse initiation, while delayed, F-actin–dependent accumulation of the RhoA GTPase-activating proteins RGA-3/4 provides negative feedback to terminate each pulse. A mathematical model, constrained by our data, suggests that this combination of feedbacks is tuned to generate locally excitable RhoA dynamics. We propose that excitable RhoA dynamics are a common driver for pulsed contractility that can be tuned or coupled differently to actomyosin dynamics to produce a diversity of morphogenetic outcomes.
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Affiliation(s)
- Jonathan B Michaux
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL
| | - François B Robin
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL
| | | | - Edwin M Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL .,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL
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18
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Lee KY, Green RA, Gutierrez E, Gomez-Cavazos JS, Kolotuev I, Wang S, Desai A, Groisman A, Oegema K. CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia. eLife 2018; 7:36919. [PMID: 29989548 PMCID: PMC6056237 DOI: 10.7554/elife.36919] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Abstract
Throughout metazoans, germ cells undergo incomplete cytokinesis to form syncytia connected by intercellular bridges. Gamete formation ultimately requires bridge closure, yet how bridges are reactivated to close is not known. The most conserved bridge component is centralspindlin, a complex of the Rho family GTPase-activating protein (GAP) CYK-4/MgcRacGAP and the microtubule motor ZEN-4/kinesin-6. Here, we show that oocyte production by the syncytial Caenorhabditis elegans germline requires CYK-4 but not ZEN-4, which contrasts with cytokinesis, where both are essential. Longitudinal imaging after conditional inactivation revealed that CYK-4 activity is important for oocyte cellularization, but not for the cytokinesis-like events that generate syncytial compartments. CYK-4’s lipid-binding C1 domain and the GTPase-binding interface of its GAP domain were both required to target CYK-4 to intercellular bridges and to cellularize oocytes. These results suggest that the conserved C1-GAP region of CYK-4 constitutes a targeting module required for closure of intercellular bridges in germline syncytia.
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Affiliation(s)
- Kian-Yong Lee
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Rebecca A Green
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Edgar Gutierrez
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - J Sebastian Gomez-Cavazos
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Irina Kolotuev
- Microscopy Rennes Imaging Center and Biosit, University of Rennes 1, Rennes, France
| | - Shaohe Wang
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Alex Groisman
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Karen Oegema
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
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19
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Abstract
Cytokinesis in metazoan cells is mediated by an actomyosin-based contractile ring that assembles in response to activation of the small GTPase RhoA. The guanine nucleotide exchange factor that activates RhoA during cytokinesis, ECT-2, is highly regulated. In most metazoan cells, with the notable exception of the early
Caenorhabditis elegans embryo, RhoA activation and furrow ingression require the centralspindlin complex. This exception is due to the existence of a parallel pathway for RhoA activation in
C. elegans. Centralspindlin contains CYK-4 which contains a predicted Rho family GTPase-activating protein (GAP) domain. The function of this domain has been the subject of considerable debate. Some publications suggest that the GAP domain promotes RhoA activation (for example, Zhang and Glotzer, 2015; Loria, Longhini and Glotzer, 2012), whereas others suggest that it functions to inactivate the GTPase Rac1 (for example, Zhuravlev
et al., 2017). Here, we review the mechanisms underlying RhoA activation during cytokinesis, primarily focusing on data in
C. elegans. We highlight the importance of considering the parallel pathway for RhoA activation and detailed analyses of
cyk-4 mutant phenotypes when evaluating the role of the GAP domain of CYK-4.
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Affiliation(s)
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
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20
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Abstract
SUMMARYCell division-cytokinesis-involves large-scale rearrangements of the entire cell. Primarily driven by cytoskeletal proteins, cytokinesis also depends on topological rearrangements of the plasma membrane, which are coordinated with nuclear division in both space and time. Despite the fundamental nature of the process, different types of eukaryotic cells show variations in both the structural mechanisms of cytokinesis and the regulatory controls. In animal cells and fungi, a contractile actomyosin-based structure plays a central, albeit flexible, role. Here, the underlying molecular mechanisms are summarized and integrated and common themes are highlighted.
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Affiliation(s)
- Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois 60637
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21
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Price KL, Rose LS. LET-99 functions in the astral furrowing pathway, where it is required for myosin enrichment in the contractile ring. Mol Biol Cell 2017; 28:2360-2373. [PMID: 28701343 PMCID: PMC5576900 DOI: 10.1091/mbc.e16-12-0874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/16/2017] [Accepted: 06/27/2017] [Indexed: 11/11/2022] Open
Abstract
LET-99 is required for furrowing during cytokinesis in both symmetrically and asymmetrically dividing cells. This function is distinct from the role of LET-99 in spindle positioning with Gα signaling. LET-99 is localized to the furrow, where it acts to promote myosin enrichment. The anaphase spindle determines the position of the cytokinesis furrow, such that the contractile ring assembles in an equatorial zone between the two spindle poles. Contractile ring formation is mediated by RhoA activation at the equator by the centralspindlin complex and midzone microtubules. Astral microtubules also inhibit RhoA accumulation at the poles. In the Caenorhabditis elegans one-cell embryo, the astral microtubule–dependent pathway requires anillin, NOP-1, and LET-99. LET-99 is well characterized for generating the asymmetric cortical localization of the Gα-dependent force-generating complex that positions the spindle during asymmetric division. However, whether the role of LET-99 in cytokinesis is specific to asymmetric division and whether it acts through Gα to promote furrowing are unclear. Here we show that LET-99 contributes to furrowing in both asymmetrically and symmetrically dividing cells, independent of its function in spindle positioning and Gα regulation. LET-99 acts in a pathway parallel to anillin and is required for myosin enrichment into the contractile ring. These and other results suggest a positive feedback model in which LET-99 localizes to the presumptive cleavage furrow in response to the spindle and myosin. Once positioned there, LET-99 enhances myosin accumulation to promote furrowing in both symmetrically and asymmetrically dividing cells.
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Affiliation(s)
- Kari L Price
- Department of Molecular and Cellular Biology and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Program, University of California, Davis, Davis, CA 95616
| | - Lesilee S Rose
- Department of Molecular and Cellular Biology and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Program, University of California, Davis, Davis, CA 95616
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22
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Von Stetina SE, Liang J, Marnellos G, Mango SE. Temporal regulation of epithelium formation mediated by FoxA, MKLP1, MgcRacGAP, and PAR-6. Mol Biol Cell 2017; 28:2042-2065. [PMID: 28539408 PMCID: PMC5509419 DOI: 10.1091/mbc.e16-09-0644] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 12/15/2022] Open
Abstract
During embryo morphogenesis, minor epithelia are generated after, and then form bridges between, major epithelia (e.g., epidermis and gut). In Caenorhabditis elegans, this delay is regulated by four proteins that control production and localization of polarity proteins: the pioneer factor PHA-4/FoxA, kinesin ZEN-4/MKLP1, its partner CYK-4/MgcRacGAP, and PAR-6. To establish the animal body plan, embryos link the external epidermis to the internal digestive tract. In Caenorhabditis elegans, this linkage is achieved by the arcade cells, which form an epithelial bridge between the foregut and epidermis, but little is known about how development of these three epithelia is coordinated temporally. The arcade cell epithelium is generated after the epidermis and digestive tract epithelia have matured, ensuring that both organs can withstand the mechanical stress of embryo elongation; mistiming of epithelium formation leads to defects in morphogenesis. Using a combination of genetic, bioinformatic, and imaging approaches, we find that temporal regulation of the arcade cell epithelium is mediated by the pioneer transcription factor and master regulator PHA-4/FoxA, followed by the cytoskeletal regulator and kinesin ZEN-4/MKLP1 and the polarity protein PAR-6. We show that PHA-4 directly activates mRNA expression of a broad cohort of epithelial genes, including junctional factor dlg-1. Accumulation of DLG-1 protein is delayed by ZEN-4, acting in concert with its binding partner CYK-4/MgcRacGAP. Our structure–function analysis suggests that nuclear and kinesin functions are dispensable, whereas binding to CYK-4 is essential, for ZEN-4 function in polarity. Finally, PAR-6 is necessary to localize polarity proteins such as DLG-1 within adherens junctions and at the apical surface, thereby generating arcade cell polarity. Our results reveal that the timing of a landmark event during embryonic morphogenesis is mediated by the concerted action of four proteins that delay the formation of an epithelial bridge until the appropriate time. In addition, we find that mammalian FoxA associates with many epithelial genes, suggesting that direct regulation of epithelial identity may be a conserved feature of FoxA factors and a contributor to FoxA function in development and cancer.
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Affiliation(s)
- Stephen E Von Stetina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Jennifer Liang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Georgios Marnellos
- Informatics and Scientific Applications, Science Division, Faculty of Arts and Sciences, Harvard University, Cambridge; MA 02138
| | - Susan E Mango
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
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23
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Breznau EB, Murt M, Blasius TL, Verhey KJ, Miller AL. The MgcRacGAP SxIP motif tethers Centralspindlin to microtubule plus ends in Xenopus laevis. J Cell Sci 2017; 130:1809-1821. [PMID: 28389580 DOI: 10.1242/jcs.195891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 04/04/2017] [Indexed: 12/27/2022] Open
Abstract
Centralspindlin, a complex of the kinesin-6-family member MKLP1 and MgcRacGAP (also known as Kif23 and Racgap1, respectively), is required for cytokinesis and cell-cell junctions. During anaphase, Centralspindlin accumulates at overlapping central spindle microtubules and directs contractile ring formation by recruiting the GEF Ect2 to the cell equator to activate RhoA. We found that MgcRacGAP localized to the plus ends of equatorial astral microtubules during cytokinesis in Xenopus laevis embryos. How MgcRacGAP is stabilized at microtubule plus ends is unknown. We identified an SxIP motif in X. laevis MgcRacGAP that is conserved with other proteins that bind to EB1 (also known as Mapre1), a microtubule plus-end tracking protein. Mutation of the SxIP motif in MgcRacGAP resulted in loss of MgcRacGAP tracking with EB3 (also known as Mapre3) on growing microtubule plus ends, abnormal astral microtubule organization, redistribution of MgcRacGAP from the contractile ring to the polar cell cortex, and mislocalization of RhoA and its downstream targets, which together contributed to severe cytokinesis defects. Furthermore, mutation of the MgcRacGAP SxIP motif perturbed adherens junctions. We propose that the MgcRacGAP SxIP motif is functionally important both for its role in regulating adherens junction structure during interphase and for regulating Rho GTPase activity during cytokinesis.
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Affiliation(s)
- Elaina B Breznau
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan Murt
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - T Lynne Blasius
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ann L Miller
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA .,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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24
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Abstract
Rho family GTPase signaling regulates the actin cytoskeleton and is critical for behaviors that range from the cell to tissue-scale. A theme in Rho GTPase biology is that there are many more regulators, such as guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), than GTPases themselves. Here, we review different, modular cases where GEFs and GAPs function together to elicit precise spatial and temporal control of signaling. We focus on examples from metazoan development, where precise regulation of Rho GTPases is critical for proper tissue form and function.
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Affiliation(s)
- Marlis Denk-Lobnig
- a Department of Biology , Massachusetts Institute of Technology , Cambridge , MA , USA
| | - Adam C Martin
- a Department of Biology , Massachusetts Institute of Technology , Cambridge , MA , USA
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25
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Zhuravlev Y, Hirsch SM, Jordan SN, Dumont J, Shirasu-Hiza M, Canman JC. CYK-4 regulates Rac, but not Rho, during cytokinesis. Mol Biol Cell 2017; 28:1258-1270. [PMID: 28298491 PMCID: PMC5415020 DOI: 10.1091/mbc.e17-01-0020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/23/2017] [Accepted: 03/02/2017] [Indexed: 12/18/2022] Open
Abstract
The roles of the Rho-family GAP CYK-4 and small GTPase Rac during cytokinesis are examined in Caenorhabditis elegans embryos. CYK-4 opposes Rac (and potentially Cdc42) activity during cytokinesis. There is no evidence that CYK-4 is upstream of Rho activity or that Rac disruption is a general suppressor of cytokinesis failure. Cytokinesis is driven by constriction of an actomyosin contractile ring that is controlled by Rho-family small GTPases. Rho, activated by the guanine-nucleotide exchange factor ECT-2, is upstream of both myosin-II activation and diaphanous formin-mediated filamentous actin (f-actin) assembly, which drive ring constriction. The role for Rac and its regulators is more controversial, but, based on the finding that Rac inactivation can rescue cytokinesis failure when the GTPase-activating protein (GAP) CYK-4 is disrupted, Rac activity was proposed to be inhibitory to contractile ring constriction and thus specifically inactivated by CYK-4 at the division plane. An alternative model proposes that Rac inactivation generally rescues cytokinesis failure by reducing cortical tension, thus making it easier for the cell to divide when ring constriction is compromised. In this alternative model, CYK-4 was instead proposed to activate Rho by binding ECT-2. Using a combination of time-lapse in vivo single-cell analysis and Caenorhabditis elegans genetics, our evidence does not support this alternative model. First, we found that Rac disruption does not generally rescue cytokinesis failure: inhibition of Rac specifically rescues cytokinesis failure due to disruption of CYK-4 or ECT-2 but does not rescue cytokinesis failure due to disruption of two other contractile ring components, the Rho effectors diaphanous formin and myosin-II. Second, if CYK-4 regulates cytokinesis through Rho rather than Rac, then CYK-4 inhibition should decrease levels of downstream targets of Rho. Inconsistent with this, we found no change in the levels of f-actin or myosin-II at the division plane when CYK-4 GAP activity was reduced, suggesting that CYK-4 is not upstream of ECT-2/Rho activation. Instead, we found that the rescue of cytokinesis in CYK-4 mutants by Rac inactivation was Cdc42 dependent. Together our data suggest that CYK-4 GAP activity opposes Rac (and perhaps Cdc42) during cytokinesis.
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Affiliation(s)
- Yelena Zhuravlev
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
| | - Sophia M Hirsch
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
| | - Shawn N Jordan
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
| | - Julien Dumont
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France
| | - Mimi Shirasu-Hiza
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032
| | - Julie C Canman
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
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26
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Thieleke-Matos C, Osório DS, Carvalho AX, Morais-de-Sá E. Emerging Mechanisms and Roles for Asymmetric Cytokinesis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 332:297-345. [PMID: 28526136 DOI: 10.1016/bs.ircmb.2017.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cytokinesis completes cell division by physically separating the contents of the mother cell between the two daughter cells. This event requires the highly coordinated reorganization of the cytoskeleton within a precise window of time to ensure faithful genomic segregation. In addition, recent progress in the field highlighted the importance of cytokinesis in providing particularly important cues in the context of multicellular tissues. The organization of the cytokinetic machinery and the asymmetric localization or inheritance of the midbody remnants is critical to define the spatial distribution of mechanical and biochemical signals. After a brief overview of the conserved steps of animal cytokinesis, we review the mechanisms controlling polarized cytokinesis focusing on the challenges of epithelial cytokinesis. Finally, we discuss the significance of these asymmetries in defining embryonic body axes, determining cell fate, and ensuring the correct propagation of epithelial organization during proliferation.
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Affiliation(s)
- C Thieleke-Matos
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Cell Division and Genomic stability, IBMC, Instituto de Biologia Molecular e Celular, and i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - D S Osório
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Cytoskeletal Dynamics, IBMC, Instituto de Biologia Molecular e Celular, and i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - A X Carvalho
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Cytoskeletal Dynamics, IBMC, Instituto de Biologia Molecular e Celular, and i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - E Morais-de-Sá
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Cell Division and Genomic stability, IBMC, Instituto de Biologia Molecular e Celular, and i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
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27
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Kotýnková K, Su KC, West SC, Petronczki M. Plasma Membrane Association but Not Midzone Recruitment of RhoGEF ECT2 Is Essential for Cytokinesis. Cell Rep 2016; 17:2672-2686. [PMID: 27926870 PMCID: PMC5177604 DOI: 10.1016/j.celrep.2016.11.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 08/29/2016] [Accepted: 11/07/2016] [Indexed: 11/27/2022] Open
Abstract
Cytokinesis, the final step of cell division, begins with the formation of a cleavage furrow. How the mitotic spindle specifies the furrow at the equator in animal cells remains unknown. Current models propose that the concentration of the RhoGEF ECT2 at the spindle midzone and the equatorial plasma membrane directs furrow formation. Using chemical genetic and optogenetic tools, we demonstrate that the association of ECT2 with the plasma membrane during anaphase is required and sufficient for cytokinesis. Local membrane targeting of ECT2 leads to unilateral furrowing, highlighting the importance of local ECT2 activity. ECT2 mutations that prevent centralspindlin binding compromise concentration of ECT2 at the midzone and equatorial membrane but sustain cytokinesis. While the association of ECT2 with the plasma membrane is essential for cytokinesis, our data suggest that ECT2 recruitment to the spindle midzone is insufficient to account for equatorial furrowing and may act redundantly with yet-uncharacterized signals.
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Affiliation(s)
- Kristýna Kotýnková
- Cell Division and Aneuploidy Laboratory, Cancer Research UK London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK; DNA Recombination and Repair Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Kuan-Chung Su
- Cell Division and Aneuploidy Laboratory, Cancer Research UK London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK; Whitehead Institute and Department of Biology, MIT, 9 Cambridge Center, Cambridge, MA 02142, USA
| | - Stephen C West
- DNA Recombination and Repair Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Mark Petronczki
- Cell Division and Aneuploidy Laboratory, Cancer Research UK London Research Institute, Clare Hall Laboratories, Blanche Lane, South Mimms, Herts EN6 3LD, UK; Boehringer Ingelheim RCV, Dr.-Boehringer-Gasse 5-11, 1121 Vienna, Austria.
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28
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Sáenz‐Narciso B, Gómez‐Orte E, Zheleva A, Gastaca I, Cabello J. Control of developmental networks by Rac/Rho small GTPases: How cytoskeletal changes during embryogenesis are orchestrated. Bioessays 2016; 38:1246-1254. [PMID: 27790724 PMCID: PMC5132145 DOI: 10.1002/bies.201600165] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Small GTPases in the Rho family act as major nodes with functions beyond cytoskeletal rearrangements shaping the Caenorhabditis elegans embryo during development. These small GTPases are key signal transducers that integrate diverse developmental signals to produce a coordinated response in the cell. In C. elegans, the best studied members of these highly conserved Rho family small GTPases, RHO-1/RhoA, CED-10/Rac, and CDC-42, are crucial in several cellular processes dealing with cytoskeletal reorganization. In this review, we update the functions described for the Rho family small GTPases in spindle orientation and cell division, engulfment, and cellular movements during C. elegans embryogenesis, focusing on the Rho subfamily Rac. Please also see the video abstract here.
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Affiliation(s)
| | - Eva Gómez‐Orte
- Center for Biomedical Research of La Rioja (CIBIR)LogroñoSpain
| | | | - Irene Gastaca
- Center for Biomedical Research of La Rioja (CIBIR)LogroñoSpain
| | - Juan Cabello
- Center for Biomedical Research of La Rioja (CIBIR)LogroñoSpain
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29
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Warga RM, Wicklund A, Webster SE, Kane DA. Progressive loss of RacGAP1/ ogre activity has sequential effects on cytokinesis and zebrafish development. Dev Biol 2016; 418:307-22. [PMID: 27339293 DOI: 10.1016/j.ydbio.2016.06.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/27/2016] [Accepted: 06/16/2016] [Indexed: 12/20/2022]
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Wagner E, Glotzer M. Local RhoA activation induces cytokinetic furrows independent of spindle position and cell cycle stage. J Cell Biol 2016; 213:641-9. [PMID: 27298323 PMCID: PMC4915195 DOI: 10.1083/jcb.201603025] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/18/2016] [Indexed: 12/14/2022] Open
Abstract
The GTPase RhoA promotes contractile ring assembly and furrow ingression during cytokinesis. Although many factors that regulate RhoA during cytokinesis have been characterized, the spatiotemporal regulatory logic remains undefined. We have developed an optogenetic probe to gain tight spatial and temporal control of RhoA activity in mammalian cells and demonstrate that cytokinetic furrowing is primarily regulated at the level of RhoA activation. Light-mediated recruitment of a RhoGEF domain to the plasma membrane leads to rapid induction of RhoA activity, leading to assembly of cytokinetic furrows that partially ingress. Furthermore, furrow formation in response to RhoA activation is not temporally or spatially restricted. RhoA activation is sufficient to generate furrows at both the cell equator and cell poles, in both metaphase and anaphase. Remarkably, furrow formation can be initiated in rounded interphase cells, but not adherent cells. These results indicate that RhoA activation is sufficient to induce assembly of functional contractile rings and that cell rounding facilitates furrow formation.
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Affiliation(s)
- Elizabeth Wagner
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
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31
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Mishima M. Centralspindlin in Rappaport’s cleavage signaling. Semin Cell Dev Biol 2016; 53:45-56. [DOI: 10.1016/j.semcdb.2016.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 03/02/2016] [Indexed: 02/07/2023]
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32
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Wernike D, Chen Y, Mastronardi K, Makil N, Piekny A. Mechanical forces drive neuroblast morphogenesis and are required for epidermal closure. Dev Biol 2016; 412:261-77. [PMID: 26923492 DOI: 10.1016/j.ydbio.2016.02.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 02/24/2016] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
Abstract
Tissue morphogenesis requires myosin-dependent events such as cell shape changes and migration to be coordinated between cells within a tissue, and/or with cells from other tissues. However, few studies have investigated the simultaneous morphogenesis of multiple tissues in vivo. We found that during Caenorhabditis elegans ventral enclosure, when epidermal cells collectively migrate to cover the ventral surface of the embryo, the underlying neuroblasts (neuronal precursor cells) also undergo morphogenesis. We found that myosin accumulates as foci along the junction-free edges of the ventral epidermal cells to form a ring, whose closure is myosin-dependent. We also observed the accumulation of myosin foci and the adhesion junction proteins E-cadherin and α-catenin in the underlying neuroblasts. Myosin may help to reorganize a subset of neuroblasts into a rosette-like pattern, and decrease their surface area as the overlying epidermal cells constrict. Since myosin is required in the neuroblasts for ventral enclosure, we propose that mechanical forces in the neuroblasts influence constriction of the overlying epidermal cells. In support of this model, disrupting neuroblast cell division or altering their fate influences myosin localization in the overlying epidermal cells. The coordination of myosin-dependent events and forces between cells in different tissues could be a common theme for coordinating morphogenetic events during metazoan development.
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Affiliation(s)
- Denise Wernike
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Yun Chen
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | | | - Neetha Makil
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, Quebec, Canada.
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van Adrichem AJ, Wennerberg K. MgcRacGAP inhibition stimulates JAK-dependent STAT3 activity. FEBS Lett 2015; 589:3859-65. [DOI: 10.1016/j.febslet.2015.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/26/2015] [Accepted: 11/11/2015] [Indexed: 10/22/2022]
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34
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van Adrichem AJ, Fagerholm A, Turunen L, Lehto A, Saarela J, Koskinen A, Repasky GA, Wennerberg K. Discovery of MINC1, a GTPase-activating protein small molecule inhibitor, targeting MgcRacGAP. Comb Chem High Throughput Screen 2015; 18:3-17. [PMID: 25479424 PMCID: PMC4435052 DOI: 10.2174/1386207318666141205112730] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 11/12/2014] [Accepted: 12/03/2014] [Indexed: 12/02/2022]
Abstract
The Rho family of Ras superfamily small GTPases regulates a broad range of biological processes such as migration, differentiation, cell growth and cell survival. Therefore, the availability of small molecule modulators as tool compounds could greatly enhance research on these proteins and their biological function. To this end, we designed a biochemical, high throughput screening assay with complementary follow-up assays to identify small molecule compounds inhibiting MgcRacGAP, a Rho family GTPase activating protein involved in cytokinesis and transcriptionally upregulated in many cancers. We first performed an in-house screen of 20,480 compounds, and later we tested the assay against 342,046 compounds from the NIH Molecular Libraries Small Molecule Repository. Primary screening hit rates were about 1% with the majority of those affecting the primary readout, an enzyme-coupled GDP detection assay. After orthogonal and counter screens, we identified two hits with high selectivity towards MgcRacGAP, compared with other RhoGAPs, and potencies in the low micromolar range. The most promising hit, termed MINC1, was then examined with cell-based testing where it was observed to induce an increased rate of cytokinetic failure and multinucleation in addition to other cell division defects, suggesting that it may act as an MgcRacGAP inhibitor also in cells.
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Affiliation(s)
| | | | | | | | | | | | | | - Krister Wennerberg
- Institute for Molecular Medicine Finland FIMM, Nordic EMBL Partnership for Molecular Medicine, Biomedicum Helsinki 2U, P.O. Box 20 (Tukholmankatu 8), FI- 00014, University of Helsinki, Finland.
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35
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Zhang D, Glotzer M. The RhoGAP activity of CYK-4/MgcRacGAP functions non-canonically by promoting RhoA activation during cytokinesis. eLife 2015; 4. [PMID: 26252513 PMCID: PMC4552957 DOI: 10.7554/elife.08898] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/06/2015] [Indexed: 12/29/2022] Open
Abstract
Cytokinesis requires activation of the GTPase RhoA. ECT-2, the exchange factor responsible for RhoA activation, is regulated to ensure spatiotemporal control of contractile ring assembly. Centralspindlin, composed of the Rho family GTPase-activating protein (RhoGAP) MgcRacGAP/CYK-4 and the kinesin MKLP1/ZEN-4, is known to activate ECT-2, but the underlying mechanism is not understood. We report that ECT-2-mediated RhoA activation depends on the ability of CYK-4 to localize to the plasma membrane, bind RhoA, and promote GTP hydrolysis by RhoA. Defects resulting from loss of CYK-4 RhoGAP activity can be rescued by activating mutations in ECT-2 or depletion of RGA-3/4, which functions as a conventional RhoGAP for RhoA. Consistent with CYK-4 RhoGAP activity contributing to GEF activation, the catalytic domains of CYK-4 and ECT-2 directly interact. Thus, counterintuitively, CYK-4 RhoGAP activity promotes RhoA activation. We propose that the most active form of the cytokinetic RhoGEF involves complex formation between ECT-2, centralspindlin and RhoA. DOI:http://dx.doi.org/10.7554/eLife.08898.001 Cell division is a process in which a cell splits to form two daughter cells. In most cases, the cell first duplicates its genetic material and then the two copies are pulled to opposite ends of the cell. A ring of protein filaments—called the contractile ring—then assembles to form a band around the cell at the site of the division. This ring contracts and the force generated separates the cells in a step known as cytokinesis. A protein belonging to the Rho family, called RhoA, is essential for cytokinesis because it controls the formation of the contractile ring. Rho proteins are switched on by the activities of other proteins called guanine nucleotide exchange factors. Another group of proteins known as ‘GTPase activating proteins’ (or GAPs for short) generally act to promote the ability of Rho proteins to turn themselves off. In animals and other multicellular organisms, a GAP called CYK-4 largely concentrates on the spindle midzone, but some of the protein also moves to part of the cell membrane near the future site of cell division. It binds to a guanine nucleotide exchange factor called ECT-2 to switch RhoA on, which in turn promotes the formation of the contractile ring. However, it is not clear why a protein that activates RhoA is also able to trigger its inactivation. In this study, Zhang and Glotzer studied cell division in a roundworm called Caenorhabditis elegans. The experiments show that cells that lacked the GAP activity of CYK-4 were unable to complete cytokinesis because RhoA was not fully switched on. This requirement could be bypassed in cells with mutant forms of ECT-2 that were overactive. Therefore, an activity that was thought to inactivate RhoA actually promotes its activation. Further experiments show that the section (or ‘domain’) of CYK-4 that has GAP activity interacts directly with the guanine nucleotide exchange domain of ECT2. Zhang and Glotzer suggest that this interaction stimulates ECT2 and thereby promotes the activation of RhoA. Further experiments will reveal how CYK-4 stimulates ECT-2. In addition, it will be important to determine whether other proteins with GAP domains also work in this unconventional way. DOI:http://dx.doi.org/10.7554/eLife.08898.002
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Affiliation(s)
- Donglei Zhang
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, United States
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36
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Breznau EB, Semack AC, Higashi T, Miller AL. MgcRacGAP restricts active RhoA at the cytokinetic furrow and both RhoA and Rac1 at cell-cell junctions in epithelial cells. Mol Biol Cell 2015; 26:2439-55. [PMID: 25947135 PMCID: PMC4571299 DOI: 10.1091/mbc.e14-11-1553] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/30/2015] [Indexed: 12/17/2022] Open
Abstract
MgcRacGAP's role in regulating the spatiotemporal dynamics of active RhoA and Rac1 in epithelial cells is investigated. MgcRacGAP's GAP activity down-regulates RhoA at the furrow and both RhoA and Rac1 at cell–cell junctions in dividing epithelial cells and is required for successful cytokinesis and cell–cell junction structure. MgcRacGAP's ability to regulate adherens junctions is dependent on GAP activity and signaling via the RhoA pathway. Localized activation of Rho GTPases is essential for multiple cellular functions, including cytokinesis and formation and maintenance of cell–cell junctions. Although MgcRacGAP (Mgc) is required for spatially confined RhoA-GTP at the equatorial cortex of dividing cells, both the target specificity of Mgc's GAP activity and the involvement of phosphorylation of Mgc at Ser-386 are controversial. In addition, Mgc's function at cell–cell junctions remains unclear. Here, using gastrula-stage Xenopus laevis embryos as a model system, we examine Mgc's role in regulating localized RhoA-GTP and Rac1-GTP in the intact vertebrate epithelium. We show that Mgc's GAP activity spatially restricts accumulation of both RhoA-GTP and Rac1-GTP in epithelial cells—RhoA at the cleavage furrow and RhoA and Rac1 at cell–cell junctions. Phosphorylation at Ser-386 does not switch the specificity of Mgc's GAP activity and is not required for successful cytokinesis. Furthermore, Mgc regulates adherens junction but not tight junction structure, and the ability to regulate adherens junctions is dependent on GAP activity and signaling via the RhoA pathway. Together these results indicate that Mgc's GAP activity down-regulates the active populations of RhoA and Rac1 at localized regions of epithelial cells and is necessary for successful cytokinesis and cell–cell junction structure.
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Affiliation(s)
- Elaina B Breznau
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ansley C Semack
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Tomohito Higashi
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ann L Miller
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109 Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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37
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Mason FM, Martin AC. Crumbling under pressure. Dev Cell 2015; 33:122-4. [PMID: 25898164 DOI: 10.1016/j.devcel.2015.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In order for an organism to maintain its form, it must be able to withstand physical perturbation, including the pull of gravity. A recent study in Nature from Porazinski and colleagues (2015) suggests that mechanisms promoting tissue tension are critical to resist the Earth's downward pull.
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Affiliation(s)
- Frank M Mason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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38
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Jing J, Chen L, Fu HY, Fan K, Yao Q, Ge YF, Lu JC, Yao B. Annexin V-induced rat Leydig cell proliferation involves Ect2 via RhoA/ROCK signaling pathway. Sci Rep 2015; 5:9437. [PMID: 25807302 PMCID: PMC5380157 DOI: 10.1038/srep09437] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/04/2015] [Indexed: 01/01/2023] Open
Abstract
This study investigated the effect of annexin V on the proliferation of primary rat Leydig cells and the potential mechanism. Our results showed that annexin V promoted rat Leydig cell proliferation and cell cycle progression in a dose- and time-dependent manner. Increased level of annexin V also enhanced Ect2 protein expression. However, siRNA knockdown of Ect2 attenuated annexin V-induced proliferation of rat Leydig cells. Taken together, these data suggest that increased level of annexin V induced rat Leydig cell proliferation and cell cycle progression via Ect2. Since RhoA activity was increased following Ect2 activation, we further investigated whether Ect2 was involved in annexin V-induced proliferation via the RhoA/ROCK pathway, and the results showed that annexin V increased RhoA activity too, and this effect was abolished by the knockdown of Ect2. Moreover, inhibition of the RhoA/ROCK pathway by a ROCK inhibitor, Y27632, also attenuated annexin V-induced proliferation and cell cycle progression. We thus conclude that Ect2 is involved in annexin V-induced rat Leydig cell proliferation through the RhoA/ROCK pathway.
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Affiliation(s)
- Jun Jing
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Li Chen
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Hai-Yan Fu
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Kai Fan
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Qi Yao
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Yi-Feng Ge
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Jin-Chun Lu
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
| | - Bing Yao
- Center of Reproductive Medicine, Nanjing Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
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Abstract
Cytokinesis mediates the physical separation of dividing cells after chromosome segregation. In animal cell cytokinesis, a contractile ring, mainly composed of actin and myosin filaments, ingresses a cleavage furrow midway between the two spindle poles. A distinct machinery, involving the endosomal sorting complex required for transport III (ESCRT-III), subsequently splits the plasma membrane of nascent daughter cells in a process termed abscission. Here, we provide a brief overview of early cytokinesis events in animal cells and then cover in depth recently emerging models for the assembly and function of the abscission machinery and its temporal coordination with chromosome segregation.
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Affiliation(s)
- Beata Mierzwa
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), 1030 Vienna, Austria.
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40
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Cannet A, Schmidt S, Delaval B, Debant A. Identification of a mitotic Rac-GEF, Trio, that counteracts MgcRacGAP function during cytokinesis. Mol Biol Cell 2014; 25:4063-71. [PMID: 25355950 PMCID: PMC4263449 DOI: 10.1091/mbc.e14-06-1153] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Inactivation of Rac1 by MgcRacGAP at the cleavage plane is essential to ensure cytokinesis. Trio activates Rac1 in dividing cells, and its depletion rescues the cytokinesis failure induced by MgcRacGAP. This work identifies for the first time a GEF-activating Rac1 in dividing cells that counteracts MgcRacGAP function in cytokinesis. The Rho GTPases RhoA and Rac1 function as master regulators of cytokinesis by controlling the actomyosin cytoskeleton. RhoA and Rac1 have to be respectively activated and inactivated at the division plane for cytokinesis to occur properly. The inactivation of Rac1 at the cleavage furrow is controlled by MgcRacGAP. However, the guanine-nucleotide exchange factor (GEF) that activates Rac1 during cell division remains unknown. Here, using a siRNA screening approach in HeLa cells, we identify Trio as a mitotic GEF of Rac1. We demonstrate that Trio controls Rac1 activation and subsequent F-actin remodeling in dividing cells. Moreover, Trio depletion specifically rescues the cytokinesis failure induced by MgcRacGAP depletion. Of importance, we demonstrate that this rescue is mediated by the Trio-Rac1 pathway, using GEF-dead mutants of Trio and a specific inhibitor of Rac1 activation by Trio. Overall this work identifies for the first time a GEF controlling Rac1 activation in dividing cells that counteracts MgcRacGAP function in cytokinesis.
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Affiliation(s)
- Aude Cannet
- Signaling and Cytoskeleton Dynamics Group, University of Montpellier, 34293 Montpellier, France
| | - Susanne Schmidt
- Signaling and Cytoskeleton Dynamics Group, University of Montpellier, 34293 Montpellier, France
| | - Bénédicte Delaval
- Centrosome, Cilia and Pathology Group, CRBM-CNRS, University of Montpellier, 34293 Montpellier, France
| | - Anne Debant
- Signaling and Cytoskeleton Dynamics Group, University of Montpellier, 34293 Montpellier, France
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41
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Manukyan A, Ludwig K, Sanchez-Manchinelly S, Parsons SJ, Stukenberg PT. A complex of p190RhoGAP-A and anillin modulates RhoA-GTP and the cytokinetic furrow in human cells. J Cell Sci 2014; 128:50-60. [PMID: 25359885 DOI: 10.1242/jcs.151647] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The cytokinetic furrow is organized by the RhoA GTPase, which recruits actin and myosin II to the furrow and drives contractility. Here, we show that the RhoA GTPase-activting protein (GAP) p190RhoGAP-A (also known as ARHGAP35) has a role in cytokinesis and is involved in regulating levels of RhoA-GTP and contractility. Cells depleted of p190RhoGAP-A accumulate high levels of RhoA-GTP and markers of high RhoA activity in the furrow, resulting in failure of the cytokinetic furrow to progress to abscission. The loss of p190RhoGAP-A can be rescued by a low dose of the myosin II inhibitor blebbistatin, suggesting that cells fail cytokinesis because they have too much myosin activity. p190RhoGAP-A binds the cytokinetic organizer anillin, and mutants of p190RhoGAP-A that are unable to bind anillin or unable to inactivate RhoA fail to rescue cytokinesis defects in p190RhoGAP-A-depleted cells. Taken together, these data demonstrate that a complex of p190RhoGAP-A and anillin modulates RhoA-GTP levels in the cytokinetic furrow to ensure progression of cytokinesis.
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Affiliation(s)
- Arkadi Manukyan
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Cancer Center, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA
| | - Kirsten Ludwig
- Cancer Center, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Department of Psychiatry and Behavioral Sciences and Jonsson Cancer Center, UCLA, Los Angeles, CA 90095-6900, USA Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA
| | - Sergio Sanchez-Manchinelly
- Cancer Center, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Beckman Corporation, Los Angeles, CA 90025, USA
| | - Sarah J Parsons
- Cancer Center, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA
| | - P Todd Stukenberg
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA Cancer Center, University of Virginia School of Medicine, PO Box 800733, Charlottesville, VA 22908, USA
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42
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Ren Y, West-Foyle H, Surcel A, Miller C, Robinson DN. Genetic suppression of a phosphomimic myosin II identifies system-level factors that promote myosin II cleavage furrow accumulation. Mol Biol Cell 2014; 25:4150-65. [PMID: 25318674 PMCID: PMC4263456 DOI: 10.1091/mbc.e14-08-1322] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
How myosin II localizes to the cleavage furrow in Dictyostelium and metazoan cells remains largely unknown despite significant advances in understanding its regulation. We designed a genetic selection using cDNA library suppression of 3xAsp myosin II to identify factors involved in myosin cleavage furrow accumulation. The 3xAsp mutant is deficient in bipolar thick filament assembly, fails to accumulate at the cleavage furrow, cannot rescue myoII-null cytokinesis, and has impaired mechanosensitive accumulation. Eleven genes suppressed this dominant cytokinesis deficiency when 3xAsp was expressed in wild-type cells. 3xAsp myosin II's localization to the cleavage furrow was rescued by constructs encoding rcdBB, mmsdh, RMD1, actin, one novel protein, and a 14-3-3 hairpin. Further characterization showed that RMD1 is required for myosin II cleavage furrow accumulation, acting in parallel with mechanical stress. Analysis of several mutant strains revealed that different thresholds of myosin II activity are required for daughter cell symmetry than for furrow ingression dynamics. Finally, an engineered myosin II with a longer lever arm (2xELC), producing a highly mechanosensitive motor, could also partially suppress the intragenic 3xAsp. Overall, myosin II accumulation is the result of multiple parallel and partially redundant pathways that comprise a cellular contractility control system.
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Affiliation(s)
- Yixin Ren
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Hoku West-Foyle
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Alexandra Surcel
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Christopher Miller
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 Summer Academic Research Experience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205 Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
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43
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Davies T, Jordan SN, Chand V, Sees JA, Laband K, Carvalho AX, Shirasu-Hiza M, Kovar DR, Dumont J, Canman JC. High-resolution temporal analysis reveals a functional timeline for the molecular regulation of cytokinesis. Dev Cell 2014; 30:209-23. [PMID: 25073157 DOI: 10.1016/j.devcel.2014.05.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 03/17/2014] [Accepted: 05/12/2014] [Indexed: 02/08/2023]
Abstract
To take full advantage of fast-acting temperature-sensitive mutations, thermal control must be extremely rapid. We developed the Therminator, a device capable of shifting sample temperature in ~17 s while simultaneously imaging cell division in vivo. Applying this technology to six key regulators of cytokinesis, we found that each has a distinct temporal requirement in the Caenorhabditis elegans zygote. Specifically, myosin-II is required throughout cytokinesis until contractile ring closure. In contrast, formin-mediated actin nucleation is only required during assembly and early contractile ring constriction. Centralspindlin is required to maintain division after ring closure, although its GAP activity is only required until just prior to closure. Finally, the chromosomal passenger complex is required for cytokinesis only early in mitosis, but not during metaphase or cytokinesis. Together, our results provide a precise functional timeline for molecular regulators of cytokinesis using the Therminator, a powerful tool for ultra-rapid protein inactivation.
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Affiliation(s)
- Tim Davies
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Shawn N Jordan
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Vandana Chand
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Jennifer A Sees
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Kimberley Laband
- CNRS, Institut Jacques Monod, Univ. P7, 75205 Paris CEDEX 13, France
| | - Ana X Carvalho
- Molecular and Cellular Biology Unit, Instituto de Biologia Molecular e Celular (IBMC), 4150-180 Porto, Portugal
| | - Mimi Shirasu-Hiza
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Julien Dumont
- CNRS, Institut Jacques Monod, Univ. P7, 75205 Paris CEDEX 13, France
| | - Julie C Canman
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
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44
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Turlier H, Audoly B, Prost J, Joanny JF. Furrow constriction in animal cell cytokinesis. Biophys J 2014; 106:114-23. [PMID: 24411243 DOI: 10.1016/j.bpj.2013.11.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 10/25/2022] Open
Abstract
Cytokinesis is the process of physical cleavage at the end of cell division; it proceeds by ingression of an acto-myosin furrow at the equator of the cell. Its failure leads to multinucleated cells and is a possible cause of tumorigenesis. Here, we calculate the full dynamics of furrow ingression and predict cytokinesis completion above a well-defined threshold of equatorial contractility. The cortical acto-myosin is identified as the main source of mechanical dissipation and active forces. Thereupon, we propose a viscous active nonlinear membrane theory of the cortex that explicitly includes actin turnover and where the active RhoA signal leads to an equatorial band of myosin overactivity. The resulting cortex deformation is calculated numerically, and reproduces well the features of cytokinesis such as cell shape and cortical flows toward the equator. Our theory gives a physical explanation of the independence of cytokinesis duration on cell size in embryos. It also predicts a critical role of turnover on the rate and success of furrow constriction. Scaling arguments allow for a simple interpretation of the numerical results and unveil the key mechanism that generates the threshold for cytokinesis completion: cytoplasmic incompressibility results in a competition between the furrow line tension and the cell poles' surface tension.
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Affiliation(s)
- Hervé Turlier
- Physicochimie Curie (Centre National de la Recherche Scientifique-UMR168), Institut Curie, Section de Recherche, Paris, France.
| | - Basile Audoly
- Institut Jean Le Rond d'Alembert (Centre National de la Recherche Scientifique-UMR7190), Université Pierre-et-Marie-Curie, Université Paris VI, Paris, France
| | - Jacques Prost
- Physicochimie Curie (Centre National de la Recherche Scientifique-UMR168), Institut Curie, Section de Recherche, Paris, France; École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris-ParisTech, Paris, France
| | - Jean-François Joanny
- Physicochimie Curie (Centre National de la Recherche Scientifique-UMR168), Institut Curie, Section de Recherche, Paris, France
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45
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Andrieu G, Quaranta M, Leprince C, Cuvillier O, Hatzoglou A. Gem GTPase acts upstream Gmip/RhoA to regulate cortical actin remodeling and spindle positioning during early mitosis. Carcinogenesis 2014; 35:2503-11. [PMID: 25173885 DOI: 10.1093/carcin/bgu185] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gem is a small guanosine triphosphate (GTP)-binding protein within the Ras superfamily, involved in the regulation of voltage-gated calcium channel activity and cytoskeleton reorganization. Gem overexpression leads to stress fiber disruption, actin and cell shape remodeling and neurite elongation in interphase cells. In this study, we show that Gem plays a crucial role in the regulation of cortical actin cytoskeleton that undergoes active remodeling during mitosis. Ectopic expression of Gem leads to cortical actin disruption and spindle mispositioning during metaphase. The regulation of spindle positioning by Gem involves its downstream effector Gmip. Knockdown of Gmip rescued Gem-induced spindle phenotype, although both Gem and Gmip accumulated at the cell cortex. In addition, we implicated RhoA GTPase as an important effector of Gem/Gmip signaling. Inactivation of RhoA by overexpressing dominant-negative mutant prevented normal spindle positioning. Introduction of active RhoA rescued the actin and spindle positioning defects caused by Gem or Gmip overexpression. These findings demonstrate a new role of Gem/Gmip/RhoA signaling in cortical actin regulation during early mitotic stages.
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Affiliation(s)
- Guillaume Andrieu
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), CNRS, F-31062 Toulouse, France, CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089, 205 route de Narbonne, BP 64182, F-31077 Toulouse, France and Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Muriel Quaranta
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), CNRS, F-31062 Toulouse, France, Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Corinne Leprince
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), CNRS, F-31062 Toulouse, France, Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Olivier Cuvillier
- CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089, 205 route de Narbonne, BP 64182, F-31077 Toulouse, France and Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
| | - Anastassia Hatzoglou
- Laboratoire de Biologie Cellulaire et Moléculaire du Contrôle de la Prolifération (LBCMCP), CNRS, F-31062 Toulouse, France, CNRS, Institut de Pharmacologie et de Biologie Structurale (IPBS), UMR 5089, 205 route de Narbonne, BP 64182, F-31077 Toulouse, France and Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France
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46
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Kotak S, Busso C, Gönczy P. NuMA interacts with phosphoinositides and links the mitotic spindle with the plasma membrane. EMBO J 2014; 33:1815-30. [PMID: 24996901 DOI: 10.15252/embj.201488147] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The positioning and the elongation of the mitotic spindle must be carefully regulated. In human cells, the evolutionary conserved proteins LGN/Gαi1-3 anchor the coiled-coil protein NuMA and dynein to the cell cortex during metaphase, thus ensuring proper spindle positioning. The mechanisms governing cortical localization of NuMA and dynein during anaphase remain more elusive. Here, we report that LGN/Gαi1-3 are dispensable for NuMA-dependent cortical dynein enrichment during anaphase. We further establish that NuMA is excluded from the equatorial region of the cell cortex in a manner that depends on the centralspindlin components CYK4 and MKLP1. Importantly, we reveal that NuMA can directly associate with PtdInsP (PIP) and PtdInsP2 (PIP2) phosphoinositides in vitro. Furthermore, chemical or enzymatic depletion of PIP/PIP2 prevents NuMA cortical localization during mitosis, and conversely, increasing PIP2 levels augments mitotic cortical NuMA. Overall, our study uncovers a novel function for plasma membrane phospholipids in governing cortical NuMA distribution and thus the proper execution of mitosis.
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Affiliation(s)
- Sachin Kotak
- School of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Coralie Busso
- School of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Pierre Gönczy
- School of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
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47
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Chircop M. Rho GTPases as regulators of mitosis and cytokinesis in mammalian cells. Small GTPases 2014; 5:29770. [PMID: 24988197 DOI: 10.4161/sgtp.29770] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases regulate a diverse range of cellular functions primarily through their ability to modulate microtubule dynamics and the actin-myosin cytoskeleton. Both of these cytoskeletal structures are crucial for a mitotic cell division. Specifically, their assembly and disassembly is tightly regulated in a temporal manner to ensure that each mitotic stage occurs in the correct sequential order and not prematurely until the previous stage is completed. Thus, it is not surprising that the Rho GTPases, RhoA, and Cdc42, have reported roles in several stages of mitosis: cell cortex stiffening during cell rounding, mitotic spindle formation, and bi-orient attachment of the spindle microtubules to the kinetochore and during cytokinesis play multiple roles in establishing the division plane, assembly, and activation of the contractile ring, membrane ingression, and abscission. Here, I review the molecular mechanisms regulating the spatial and temporal activation of RhoA and Cdc42 during mitosis, and how this is critical for mitotic progression and completion.
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Affiliation(s)
- Megan Chircop
- Children's Medical Research Institute; The University of Sydney; Westmead, Australia
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48
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David MD, Petit D, Bertoglio J. The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes. J Cell Sci 2013; 127:400-10. [PMID: 24259668 DOI: 10.1242/jcs.135079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Small GTP-binding proteins of the Rho family orchestrate the cytoskeleton remodelling events required for cell division. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) promote cycling of Rho GTPases between the active GTP-bound and the inactive GDP-bound conformations. We report that ARHGAP19, a previously uncharacterised protein, is predominantly expressed in hematopoietic cells and has an essential role in the division of T lymphocytes. Overexpression of ARHGAP19 in lymphocytes delays cell elongation and cytokinesis. Conversely, silencing of ARHGAP19 or expression of a GAP-deficient mutant induces precocious mitotic cell elongation and cleavage furrow ingression, as well as excessive blebbing. In relation to these phenotypes, we show that ARHGAP19 acts as a GAP for RhoA, and controls recruitment of citron and myosin II to the plasma membrane of mitotic lymphocytes as well as Rock2-mediated phosphorylation of vimentin, which is crucial to maintain the stiffness and shape of lymphocytes. In addition to its effects on cell shape, silencing of ARHGAP19 in lymphocytes also impairs chromosome segregation.
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Affiliation(s)
- Muriel D David
- Inserm U749, Institut Gustave Roussy, 94805 Villejuif, France
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49
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Caenorhabditis elegans anillin (ani-1) regulates neuroblast cytokinesis and epidermal morphogenesis during embryonic development. Dev Biol 2013; 383:61-74. [DOI: 10.1016/j.ydbio.2013.08.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 08/24/2013] [Accepted: 08/27/2013] [Indexed: 11/23/2022]
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50
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Akhshi TK, Wernike D, Piekny A. Microtubules and actin crosstalk in cell migration and division. Cytoskeleton (Hoboken) 2013; 71:1-23. [DOI: 10.1002/cm.21150] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 12/22/2022]
Affiliation(s)
| | - Denise Wernike
- Department of Biology; Concordia University; Montreal Quebec Canada
| | - Alisa Piekny
- Department of Biology; Concordia University; Montreal Quebec Canada
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