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Robinson J, Teuliere J, Yoo S, Garriga G. NMY-2, TOE-2 and PIG-1 regulate Caenorhabditis elegans asymmetric cell divisions. PLoS One 2024; 19:e0304064. [PMID: 38787850 PMCID: PMC11125515 DOI: 10.1371/journal.pone.0304064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Asymmetric cell division is an important mechanism that generates cellular diversity during development. Not only do asymmetric cell divisions produce daughter cells of different fates, but many can also produce daughters of different sizes, which we refer to as Daughter Cell Size Asymmetry (DCSA). In Caenorhabditis elegans, apoptotic cells are frequently produced by asymmetric divisions that exhibit DCSA, where the smaller daughter dies. We focus here on the divisions of the Q.a and Q.p neuroblasts, which produce larger surviving cells and smaller apoptotic cells and divide with opposite polarity using both distinct and overlapping mechanisms. Several proteins regulate DCSA in these divisions. Previous studies showed that the PIG-1/MELK and TOE-2 proteins regulate DCSA in both the Q.a and Q.p divisions, and the non-muscle myosin NMY-2 regulates DCSA in the Q.a division but not the Q.p division. In this study, we examined endogenously tagged NMY-2, TOE-2, and PIG-1 reporters and characterized their distribution at the cortex during the Q.a and Q.p divisions. In both divisions, TOE-2 localized toward the side of the dividing cell that produced the smaller daughter, whereas PIG-1 localized toward the side that produced the larger daughter. As previously reported, NMY-2 localized to the side of Q.a that produced the smaller daughter and did not localize asymmetrically in Q.p. We used temperature-sensitive nmy-2 mutants to determine the role of nmy-2 in these divisions and were surprised to find that these mutants only displayed DCSA defects in the Q.p division. We generated double mutant combinations between the nmy-2 mutations and mutations in toe-2 and pig-1. Because previous studies indicate that DCSA defects result in the transformation of cells fated to die into their sister cells, the finding that the nmy-2 mutations did not significantly alter the Q.a and Q.p DCSA defects of toe-2 and pig-1 mutants but did alter the number of daughter cells produced by Q.a and Q.p suggests that nmy-2 plays a role in specifying the fates of the Q.a and Q.p that is independent of its role in DCSA.
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Affiliation(s)
- Joseph Robinson
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States of America
| | - Jerome Teuliere
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States of America
| | - Shinja Yoo
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States of America
| | - Gian Garriga
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, United States of America
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2
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Rodriguez-Polanco WR, Norris A, Velasco AB, Gleason AM, Grant BD. Syndapin and GTPase RAP-1 control endocytic recycling via RHO-1 and non-muscle myosin II. Curr Biol 2023; 33:4844-4856.e5. [PMID: 37832552 PMCID: PMC10841897 DOI: 10.1016/j.cub.2023.09.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/07/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023]
Abstract
After endocytosis, many plasma membrane components are recycled via membrane tubules that emerge from early endosomes to form recycling endosomes, eventually leading to their return to the plasma membrane. We previously showed that Syndapin/PACSIN-family protein SDPN-1 is required in vivo for basolateral endocytic recycling in the C. elegans intestine. Here, we document an interaction between the SDPN-1 SH3 domain and a target sequence in PXF-1/PDZ-GEF1/RAPGEF2, a known exchange factor for Rap-GTPases. We found that endogenous mutations engineered into the SDPN-1 SH3 domain, or its binding site in the PXF-1 protein, interfere with recycling in vivo, as does the loss of the PXF-1 target RAP-1. In some contexts, Rap-GTPases negatively regulate RhoA activity, suggesting a potential for Syndapin to regulate RhoA. Our results indicate that in the C. elegans intestine, RHO-1/RhoA is enriched on SDPN-1- and RAP-1-positive endosomes, and the loss of SDPN-1 or RAP-1 elevates RHO-1(GTP) levels on intestinal endosomes. Furthermore, we found that depletion of RHO-1 suppressed sdpn-1 mutant recycling defects, indicating that control of RHO-1 activity is a key mechanism by which SDPN-1 acts to promote endocytic recycling. RHO-1/RhoA is well known for controlling actomyosin contraction cycles, although little is known about the effects of non-muscle myosin II on endosomes. Our analysis found that non-muscle myosin II is enriched on SDPN-1-positive endosomes, with two non-muscle myosin II heavy-chain isoforms acting in apparent opposition. Depletion of nmy-2 inhibited recycling like sdpn-1 mutants, whereas depletion of nmy-1 suppressed sdpn-1 mutant recycling defects, indicating that actomyosin contractility controls recycling endosome function.
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Affiliation(s)
| | - Anne Norris
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Agustin B Velasco
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Adenrele M Gleason
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA; Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA; Rutgers Center for Lipid Research, Rutgers, the State University of New Jersey, New Brunswick, NJ 08901-8521, USA.
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3
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Rodriguez-Polanco WR, Norris A, Velasco AB, Gleason AM, Grant BD. Syndapin Regulates the RAP-1 GTPase to Control Endocytic Recycling via RHO-1 and Non-Muscle Myosin II. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530328. [PMID: 36909525 PMCID: PMC10002613 DOI: 10.1101/2023.02.27.530328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
After endocytosis, many plasma membrane components are recycled via narrow-diameter membrane tubules that emerge from early endosomes to form recycling endosomes, eventually leading to their return to the plasma membrane. We previously showed that the F-BAR and SH3 domain Syndapin/PACSIN-family protein SDPN-1 is required in vivo for basolateral endocytic recycling in the C. elegans intestine. Here we sought to determine the significance of a predicted interaction between the SDPN-1 SH3 domain and a target sequence in PXF-1/PDZ-GEF1/RAPGEF2, a known exchange factor for Rap-GTPases. We found that endogenous mutations we engineered into the SDPN-1 SH3 domain, or its binding site in the PXF-1 protein, interfere with recycling in vivo , as does loss of the PXF-1 target RAP-1. Rap-GTPases have been shown in several contexts to negatively regulate RhoA activity. Our results show that RHO-1/RhoA is enriched on SDPN-1 and RAP-1 positive endosomes in the C. elegans intestine, and loss of SDPN-1 or RAP-1 elevates RHO-1(GTP) levels on intestinal endosomes. Furthermore, we found that depletion of RHO-1 suppressed sdpn-1 mutant recycling defects, indicating that control of RHO-1 activity is a key mechanism by which SDPN-1 acts to promote endocytic recycling. RHO-1/RhoA is well-known for controlling actomyosin contraction cycles, although little is known of non-muscle myosin II on endosomes. Our analysis found that non-muscle myosin II is enriched on SDPN-1 positive endosomes, with two non-muscle myosin II heavy chain isoforms acting in apparent opposition. Depletion of nmy-2 inhibited recycling like sdpn-1 mutants, while depletion of nmy-1 suppressed sdpn-1 mutant recycling defects, indicating actomyosin contractility in controlling recycling endosome function.
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4
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Singh J, Imran Alsous J, Garikipati K, Shvartsman SY. Mechanics of stabilized intercellular bridges. Biophys J 2022; 121:3162-3171. [PMID: 35778841 PMCID: PMC9463629 DOI: 10.1016/j.bpj.2022.06.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/04/2022] [Accepted: 06/27/2022] [Indexed: 11/02/2022] Open
Abstract
Numerous engineered and natural systems form through reinforcement and stabilization of a deformed configuration that was generated by a transient force. An important class of such structures arises during gametogenesis, when a dividing cell undergoes incomplete cytokinesis, giving rise to daughter cells that remain connected through a stabilized intercellular bridge (ICB). ICBs can form through arrest of the contractile cytokinetic furrow and its subsequent stabilization. Despite knowledge of the molecular components, the mechanics underlying robust ICB assembly and the interplay between ring contractility and stiffening are poorly understood. Here, we report joint experimental and theoretical work that explores the physics underlying robust ICB assembly. We develop a continuum mechanics model that reveals the minimal requirements for the formation of stable ICBs, and validate the model's equilibrium predictions through a tabletop experimental analog. With insight into the equilibrium states, we turn to the dynamics: we demonstrate that contractility and stiffening are in dynamic competition and that the time intervals of their action must overlap to ensure assembly of ICBs of biologically observed proportions. Our results highlight a mechanism in which deformation and remodeling are tightly coordinated-one that is applicable to several mechanics-based applications and is a common theme in biological systems spanning several length scales.
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Affiliation(s)
- Jaspreet Singh
- Center for Computational Biology, Flatiron Institute, New York, New York
| | | | - Krishna Garikipati
- Departments of Mechanical Engineering, and Mathematics, Michigan Institute for Computational Discovery & Engineering, University of Michigan, Ann Arbor, Michigan.
| | - Stanislav Y Shvartsman
- Department of Molecular Biology, Princeton University, Princeton, New Jersey; The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey.
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5
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Ciocanel MV, Chandrasekaran A, Mager C, Ni Q, Papoian GA, Dawes A. Simulated actin reorganization mediated by motor proteins. PLoS Comput Biol 2022; 18:e1010026. [PMID: 35389987 PMCID: PMC9017880 DOI: 10.1371/journal.pcbi.1010026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 04/19/2022] [Accepted: 03/15/2022] [Indexed: 11/24/2022] Open
Abstract
Cortical actin networks are highly dynamic and play critical roles in shaping the mechanical properties of cells. The actin cytoskeleton undergoes significant reorganization in many different contexts, including during directed cell migration and over the course of the cell cycle, when cortical actin can transition between different configurations such as open patched meshworks, homogeneous distributions, and aligned bundles. Several types of myosin motor proteins, characterized by different kinetic parameters, have been involved in this reorganization of actin filaments. Given the limitations in studying the interactions of actin with myosin in vivo, we propose stochastic agent-based models and develop a set of data analysis measures to assess how myosin motor proteins mediate various actin organizations. In particular, we identify individual motor parameters, such as motor binding rate and step size, that generate actin networks with different levels of contractility and different patterns of myosin motor localization, which have previously been observed experimentally. In simulations where two motor populations with distinct kinetic parameters interact with the same actin network, we find that motors may act in a complementary way, by tuning the actin network organization, or in an antagonistic way, where one motor emerges as dominant. This modeling and data analysis framework also uncovers parameter regimes where spatial segregation between motor populations is achieved. By allowing for changes in kinetic rates during the actin-myosin dynamic simulations, our work suggests that certain actin-myosin organizations may require additional regulation beyond mediation by motor proteins in order to reconfigure the cytoskeleton network on experimentally-observed timescales. Cell shape is dictated by a scaffolding network called the cytoskeleton. Actin filaments, a main component of the cytoskeleton, are found predominantly at the periphery of the cell, where they organize into different patterns in response to various stimuli, such as progression through the cell cycle. The actin filament reorganizations are mediated by motor proteins from the myosin superfamily. Using a realistic stochastic model that simulates actin filament and motor protein dynamics and interactions, we systematically vary motor protein kinetics and investigate their effect on actin filament organization. Using novel measures of spatial organization, we quantify conditions under which motor proteins, either alone or in combination, can produce the different actin filament organizations observed in vitro and in vivo. These results yield new insights into the role of motor proteins, as well as into how multiple types of motors can work collectively to produce specific actomyosin network patterns.
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Affiliation(s)
- Maria-Veronica Ciocanel
- Department of Mathematics and Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
| | - Aravind Chandrasekaran
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, United States of America
| | - Carli Mager
- Department of Biochemistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Qin Ni
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland, United States of America
| | - Garegin A. Papoian
- Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, United States of America
| | - Adriana Dawes
- Department of Mathematics and Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
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6
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Cicconofri G, Noselli G, DeSimone A. The biomechanical role of extra-axonemal structures in shaping the flagellar beat of Euglena gracilis. eLife 2021; 10:58610. [PMID: 33899736 PMCID: PMC8075587 DOI: 10.7554/elife.58610] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 02/12/2021] [Indexed: 01/01/2023] Open
Abstract
We propose and discuss a model for flagellar mechanics in Euglena gracilis. We show that the peculiar non-planar shapes of its beating flagellum, dubbed 'spinning lasso', arise from the mechanical interactions between two of its inner components, namely, the axoneme and the paraflagellar rod. The spontaneous shape of the axoneme and the resting shape of the paraflagellar rod are incompatible. Thus, the complex non-planar configurations of the coupled system emerge as the energetically optimal compromise between the two antagonistic components. The model is able to reproduce the experimentally observed flagellar beats and the characteristic geometric signature of spinning lasso, namely, traveling waves of torsion with alternating sign along the length of the flagellum.
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Affiliation(s)
| | - Giovanni Noselli
- SISSA - International School for Advanced Studies, Trieste, Italy
| | - Antonio DeSimone
- SISSA - International School for Advanced Studies, Trieste, Italy.,The BioRobotics Institute, Scuola Superiore Sant'Anna, Trieste, Italy
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7
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Ciocanel MV, Juenemann R, Dawes AT, McKinley SA. Topological Data Analysis Approaches to Uncovering the Timing of Ring Structure Onset in Filamentous Networks. Bull Math Biol 2021; 83:21. [PMID: 33452960 PMCID: PMC7811524 DOI: 10.1007/s11538-020-00847-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/11/2020] [Indexed: 11/30/2022]
Abstract
In developmental biology as well as in other biological systems, emerging structure and organization can be captured using time-series data of protein locations. In analyzing this time-dependent data, it is a common challenge not only to determine whether topological features emerge, but also to identify the timing of their formation. For instance, in most cells, actin filaments interact with myosin motor proteins and organize into polymer networks and higher-order structures. Ring channels are examples of such structures that maintain constant diameters over time and play key roles in processes such as cell division, development, and wound healing. Given the limitations in studying interactions of actin with myosin in vivo, we generate time-series data of protein polymer interactions in cells using complex agent-based models. Since the data has a filamentous structure, we propose sampling along the actin filaments and analyzing the topological structure of the resulting point cloud at each time. Building on existing tools from persistent homology, we develop a topological data analysis (TDA) method that assesses effective ring generation in this dynamic data. This method connects topological features through time in a path that corresponds to emergence of organization in the data. In this work, we also propose methods for assessing whether the topological features of interest are significant and thus whether they contribute to the formation of an emerging hole (ring channel) in the simulated protein interactions. In particular, we use the MEDYAN simulation platform to show that this technique can distinguish between the actin cytoskeleton organization resulting from distinct motor protein binding parameters.
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Affiliation(s)
| | - Riley Juenemann
- Department of Mathematics, Tulane University, New Orleans, USA
| | - Adriana T Dawes
- Department of Mathematics and Department of Molecular Genetics, The Ohio State University, Columbus, USA
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8
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Kumar H, Pushpa K, Kumari A, Verma K, Pergu R, Mylavarapu SVS. The exocyst complex and Rab5 are required for abscission by localizing ESCRT III subunits to the cytokinetic bridge. J Cell Sci 2019; 132:jcs.226001. [PMID: 31221728 PMCID: PMC6679584 DOI: 10.1242/jcs.226001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 06/14/2019] [Indexed: 01/26/2023] Open
Abstract
Cytokinesis is the final step of cell division following chromosome segregation that generates two daughter cells. The conserved exocyst complex is required for scission of the intercellular cytokinetic bridge, although the molecular mechanisms it employs in this process are unclear. We identify and validate the early endocytic GTPase Rab5 as interacting with the exocyst complex in mammalian cells. Rab5 localizes in the cytokinetic bridge and on the midbody ring in a manner similar to the exocyst complex. Depletion of Rab5 led to delayed abscission. Caenorhabditis elegans orthologs of both exocyst complex subunits and Rab5 localize along the cleavage furrow and are required for cytokinesis in early embryos. Cytokinetic cells depleted of either Rab5 or the exocyst subunits Exoc3 and Exoc4 showed impaired deposition of the endosomal sorting complexes required for transport (ESCRT) III subunits CHMP2B and/or CHMP4B near the midbody ring. The study reveals an evolutionarily conserved role for the early endocytic marker Rab5 in cytokinetic abscission. In addition, it uncovers a key requirement of the exocyst and Rab5 for the delivery of components of the membrane-severing ESCRT III machinery to complete cytokinesis. Summary: The conserved exocytic vesicle-tethering exocyst complex and the endocytic master regulator Rab5 mutually interact and are required to deliver the ESCRT III membrane scission apparatus for completion of cytokinesis.
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Affiliation(s)
- Harsh Kumar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Kumari Pushpa
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Amrita Kumari
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Kuldeep Verma
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Rajaiah Pergu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Sivaram V S Mylavarapu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India .,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
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9
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Syncytial germline architecture is actively maintained by contraction of an internal actomyosin corset. Nat Commun 2018; 9:4694. [PMID: 30410005 PMCID: PMC6224597 DOI: 10.1038/s41467-018-07149-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 10/09/2018] [Indexed: 01/13/2023] Open
Abstract
Syncytial architecture is an evolutionarily-conserved feature of the germline of many species and plays a crucial role in their fertility. However, the mechanism supporting syncytial organization is largely unknown. Here, we identify a corset-like actomyosin structure within the syncytial germline of Caenorhabditis elegans, surrounding the common rachis. Using laser microsurgery, we demonstrate that actomyosin contractility within this structure generates tension both in the plane of the rachis surface and perpendicular to it, opposing membrane tension. Genetic and pharmacological perturbations, as well as mathematical modeling, reveal a balance of forces within the gonad and show how changing the tension within the actomyosin corset impinges on syncytial germline structure, leading, in extreme cases, to sterility. Thus, our work highlights a unique tissue-level cytoskeletal structure, and explains the critical role of actomyosin contractility in the preservation of a functional germline. Germline cells in many species are fused to form a syncytium but the mechanics behind the maintenance of these structures are poorly defined. Here, the authors propose an inner contractile actomyosin corset provides a supportive framework to maintain germline architecture in C. elegans.
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10
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Rehain-Bell K, Love A, Werner ME, MacLeod I, Yates JR, Maddox AS. A Sterile 20 Family Kinase and Its Co-factor CCM-3 Regulate Contractile Ring Proteins on Germline Intercellular Bridges. Curr Biol 2017; 27:860-867. [PMID: 28285996 DOI: 10.1016/j.cub.2017.01.058] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/18/2016] [Accepted: 01/27/2017] [Indexed: 11/19/2022]
Abstract
Germ cells in most animals are connected by intercellular bridges, actin-based rings that form stable cytoplasmic connections between cells promoting communication and coordination [1]. Moreover, these connections are required for fertility [1, 2]. Intercellular bridges are proposed to arise from stabilization of the cytokinetic ring during incomplete cytokinesis [1]. Paradoxically, proteins that promote closure of cytokinetic rings are enriched on stably open intercellular bridges [1, 3, 4]. Given this inconsistency, the mechanism of intercellular bridge stabilization is unclear. Here, we used the C. elegans germline as a model for identifying molecular mechanisms regulating intercellular bridges. We report that bridges are actually highly dynamic, changing size at precise times during germ cell development. We focused on the regulation of bridge stability by anillins, key regulators of cytokinetic rings and cytoplasmic bridges [1, 4-7]. We identified GCK-1, a conserved serine/threonine kinase [8], as a putative novel anillin interactor. GCK-1 works together with CCM-3, a known binding partner [9], to promote intercellular bridge stability and limit localization of both canonical anillin and non-muscle myosin II (NMM-II) to intercellular bridges. Additionally, we found that a shorter anillin, known to stabilize bridges [4, 7], also regulates NMM-II levels at bridges. Consistent with these results, negative regulators of NMM-II stabilize intercellular bridges in the Drosophila egg chamber [10, 11]. Together with our findings, this suggests that tuning of myosin levels is a conserved mechanism for the stabilization of intercellular bridges that can occur by diverse molecular mechanisms.
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Affiliation(s)
- Kathryn Rehain-Bell
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Andrew Love
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael E Werner
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ian MacLeod
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John R Yates
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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