51
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Letizia A, He D, Astigarraga S, Colombelli J, Hatini V, Llimargas M, Treisman JE. Sidekick Is a Key Component of Tricellular Adherens Junctions that Acts to Resolve Cell Rearrangements. Dev Cell 2019; 50:313-326.e5. [PMID: 31353315 DOI: 10.1016/j.devcel.2019.07.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/03/2019] [Accepted: 07/02/2019] [Indexed: 11/27/2022]
Abstract
Tricellular adherens junctions are points of high tension that are central to the rearrangement of epithelial cells. However, the molecular composition of these junctions is unknown, making it difficult to assess their role in morphogenesis. Here, we show that Sidekick, an immunoglobulin family cell adhesion protein, is highly enriched at tricellular adherens junctions in Drosophila. This localization is modulated by tension, and Sidekick is itself necessary to maintain normal levels of cell bond tension. Loss of Sidekick causes defects in cell and junctional rearrangements in actively remodeling epithelial tissues like the retina and tracheal system. The adaptor proteins Polychaetoid and Canoe are enriched at tricellular adherens junctions in a Sidekick-dependent manner; Sidekick functionally interacts with both proteins and directly binds to Polychaetoid. We suggest that Polychaetoid and Canoe link Sidekick to the actin cytoskeleton to enable tricellular adherens junctions to maintain or transmit cell bond tension during epithelial cell rearrangements.
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Affiliation(s)
- Annalisa Letizia
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain
| | - DanQing He
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Sergio Astigarraga
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Julien Colombelli
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Parc Científic de Barcelona, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Victor Hatini
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, 150 Harrison Avenue, Jaharis 322, Boston, MA 02111, USA
| | - Marta Llimargas
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA.
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52
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Ko CS, Tserunyan V, Martin AC. Microtubules promote intercellular contractile force transmission during tissue folding. J Cell Biol 2019; 218:2726-2742. [PMID: 31227595 PMCID: PMC6683747 DOI: 10.1083/jcb.201902011] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/30/2019] [Accepted: 05/23/2019] [Indexed: 12/19/2022] Open
Abstract
During development, forces transmitted between cells are critical for sculpting epithelial tissues. Actomyosin contractility in the middle of the cell apex (medioapical) can change cell shape (e.g., apical constriction) but can also result in force transmission between cells via attachments to adherens junctions. How actomyosin networks maintain attachments to adherens junctions under tension is poorly understood. Here, we discovered that microtubules promote actomyosin intercellular attachments in epithelia during Drosophila melanogaster mesoderm invagination. First, we used live imaging to show a novel arrangement of the microtubule cytoskeleton during apical constriction: medioapical Patronin (CAMSAP) foci formed by actomyosin contraction organized an apical noncentrosomal microtubule network. Microtubules were required for mesoderm invagination but were not necessary for initiating apical contractility or adherens junction assembly. Instead, microtubules promoted connections between medioapical actomyosin and adherens junctions. These results delineate a role for coordination between actin and microtubule cytoskeletal systems in intercellular force transmission during tissue morphogenesis.
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Affiliation(s)
- Clint S Ko
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Vardges Tserunyan
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
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53
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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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54
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D'Angelo A, Dierkes K, Carolis C, Salbreux G, Solon J. In Vivo Force Application Reveals a Fast Tissue Softening and External Friction Increase during Early Embryogenesis. Curr Biol 2019; 29:1564-1571.e6. [PMID: 31031116 PMCID: PMC6509404 DOI: 10.1016/j.cub.2019.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 02/06/2019] [Accepted: 04/03/2019] [Indexed: 11/23/2022]
Abstract
During development, cell-generated forces induce tissue-scale deformations to shape the organism [1,2]. The pattern and extent of these deformations depend not solely on the temporal and spatial profile of the generated force fields but also on the mechanical properties of the tissues that the forces act on. It is thus conceivable that, much like the cell-generated forces, the mechanical properties of tissues are modulated during development in order to drive morphogenesis toward specific developmental endpoints. Although many approaches have recently emerged to assess effective mechanical parameters of tissues [3-8], they could not quantitatively relate spatially localized force induction to tissue-scale deformations in vivo. Here, we present a method that overcomes this limitation. Our approach is based on the application of controlled forces on a single microparticle embedded in an individual cell of an embryo. Combining measurements of bead displacement with the analysis of induced deformation fields in a continuum mechanics framework, we quantify material properties of the tissue and follow their changes over time. In particular, we uncover a rapid change in tissue response occurring during Drosophila cellularization, resulting from a softening of the blastoderm and an increase of external friction. We find that the microtubule cytoskeleton is a major contributor to epithelial mechanics at this stage. We identify developmentally controlled modulations in perivitelline spacing that can account for the changes in friction. Overall, our method allows for the measurement of key mechanical parameters governing tissue-scale deformations and flows occurring during morphogenesis.
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Affiliation(s)
- Arturo D'Angelo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Kai Dierkes
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Carlo Carolis
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | | | - Jérôme Solon
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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55
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Saha S, Nagy TL, Weiner OD. Joining forces: crosstalk between biochemical signalling and physical forces orchestrates cellular polarity and dynamics. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0145. [PMID: 29632270 DOI: 10.1098/rstb.2017.0145] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2017] [Indexed: 12/11/2022] Open
Abstract
Dynamic processes like cell migration and morphogenesis emerge from the self-organized interaction between signalling and cytoskeletal rearrangements. How are these molecular to sub-cellular scale processes integrated to enable cell-wide responses? A growing body of recent studies suggest that forces generated by cytoskeletal dynamics and motor activity at the cellular or tissue scale can organize processes ranging from cell movement, polarity and division to the coordination of responses across fields of cells. To do so, forces not only act mechanically but also engage with biochemical signalling. Here, we review recent advances in our understanding of this dynamic crosstalk between biochemical signalling, self-organized cortical actomyosin dynamics and physical forces with a special focus on the role of membrane tension in integrating cellular motility.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Suvrajit Saha
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - Tamas L Nagy
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA.,Biological and Medical Informatics Graduate Program, University of California, San Francisco, CA 94158, USA
| | - Orion D Weiner
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA .,Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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56
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Hunter GL, He L, Perrimon N, Charras G, Giniger E, Baum B. A role for actomyosin contractility in Notch signaling. BMC Biol 2019; 17:12. [PMID: 30744634 PMCID: PMC6369551 DOI: 10.1186/s12915-019-0625-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/04/2019] [Indexed: 12/24/2022] Open
Abstract
Background Notch-Delta signaling functions across a wide array of animal systems to break symmetry in a sheet of undifferentiated cells and generate cells with different fates, a process known as lateral inhibition. Unlike many other signaling systems, however, since both the ligand and receptor are transmembrane proteins, the activation of Notch by Delta depends strictly on cell-cell contact. Furthermore, the binding of the ligand to the receptor may not be sufficient to induce signaling, since recent work in cell culture suggests that ligand-induced Notch signaling also requires a mechanical pulling force. This tension exposes a cleavage site in Notch that, when cut, activates signaling. Although it is not known if mechanical tension contributes to signaling in vivo, others have suggested that this is how endocytosis of the receptor-ligand complex contributes to the cleavage and activation of Notch. In a similar way, since Notch-mediated lateral inhibition at a distance in the dorsal thorax of the pupal fly is mediated via actin-rich protrusions, it is possible that cytoskeletal forces generated by networks of filamentous actin and non-muscle myosin during cycles of protrusion extension and retraction also contribute to Notch signaling. Results To test this hypothesis, we carried out a detailed analysis of the role of myosin II-dependent tension in Notch signaling in the developing fly and in cell culture. Using dynamic fluorescence-based reporters of Notch, we found that myosin II is important for signaling in signal sending and receiving cells in both systems—as expected if myosin II-dependent tension across the Notch-Delta complex contributes to Notch activation. While myosin II was found to contribute most to signaling at a distance, it was also required for maximal signaling between adjacent cells that share lateral contacts and for signaling between cells in culture. Conclusions Together these results reveal a previously unappreciated role for non-muscle myosin II contractility in Notch signaling, providing further support for the idea that force contributes to the cleavage and activation of Notch in the context of ligand-dependent signaling, and a new paradigm for actomyosin-based mechanosensation. Electronic supplementary material The online version of this article (10.1186/s12915-019-0625-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ginger L Hunter
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA. .,MRC-LMCB, University College London, London, WC1E6BT, UK. .,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK. .,Present Address: Department of Biology, Clarkson University, Potsdam, NY, 13699, USA.
| | - Li He
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London, WC1E6BT, UK.,Department of Cell and Developmental Biology, University College London, London, WC1E6BT, UK
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA.
| | - Buzz Baum
- MRC-LMCB, University College London, London, WC1E6BT, UK.,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK
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57
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Yu Q, Li J, Murrell MP, Kim T. Balance between Force Generation and Relaxation Leads to Pulsed Contraction of Actomyosin Networks. Biophys J 2018; 115:2003-2013. [PMID: 30389091 PMCID: PMC6303541 DOI: 10.1016/j.bpj.2018.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/23/2018] [Accepted: 10/05/2018] [Indexed: 01/07/2023] Open
Abstract
Actomyosin contractility regulates various biological processes, including cell migration and cytokinesis. The cell cortex underlying the membrane of eukaryote cells exhibits dynamic contractile behaviors facilitated by actomyosin contractility. Interestingly, the cell cortex shows reversible aggregation of actin and myosin called "pulsed contraction" in diverse cellular phenomena, such as embryogenesis and tissue morphogenesis. Although contractile behaviors of actomyosin machinery have been studied extensively in several in vitro experiments and computational studies, none of them successfully reproduced the pulsed contraction observed in vivo. Recent experiments have suggested the pulsed contraction is dependent upon the spatiotemporal expression of a small GTPase protein called RhoA. This only indicates the significance of biochemical signaling pathways during the pulsed contraction. In this study, we reproduced the pulsed contraction with only the mechanical and dynamic behaviors of cytoskeletal elements. First, we observed that small pulsed clusters or clusters with fluctuating sizes may appear when there is subtle balance between force generation from motors and force relaxation induced by actin turnover. However, the size and duration of these clusters differ from those of clusters observed during the cellular phenomena. We found that clusters with physiologically relevant size and duration can appear only with both actin turnover and angle-dependent F-actin severing resulting from buckling induced by motor activities. We showed how parameters governing F-actin severing events regulate the size and duration of pulsed clusters. Our study sheds light on the underestimated significance of F-actin severing for the pulsed contraction observed in physiological processes.
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Affiliation(s)
- Qilin Yu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Jing Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut; Systems Biology Institute, Yale University, West Haven, Connecticut
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana.
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58
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Visetsouk MR, Falat EJ, Garde RJ, Wendlick JL, Gutzman JH. Basal epithelial tissue folding is mediated by differential regulation of microtubules. Development 2018; 145:dev.167031. [PMID: 30333212 PMCID: PMC6262788 DOI: 10.1242/dev.167031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 10/09/2018] [Indexed: 01/02/2023]
Abstract
The folding of epithelial tissues is crucial for development of three-dimensional structure and function. Understanding this process can assist in determining the etiology of developmental disease and engineering of tissues for the future of regenerative medicine. Folding of epithelial tissues towards the apical surface has long been studied, but the molecular mechanisms that mediate epithelial folding towards the basal surface are just emerging. Here, we utilize zebrafish neuroepithelium to identify mechanisms that mediate basal tissue folding to form the highly conserved embryonic midbrain-hindbrain boundary. Live imaging revealed Wnt5b as a mediator of anisotropic epithelial cell shape, both apically and basally. In addition, we uncovered a Wnt5b-mediated mechanism for specific regulation of basal anisotropic cell shape that is microtubule dependent and likely to involve JNK signaling. We propose a model in which a single morphogen can differentially regulate apical versus basal cell shape during tissue morphogenesis. Summary: Examination of cell shape changes during zebrafish neuroepithelium tissue folding reveals that Wnt5b specifically regulates basal anisotropic cell shape via a microtubule-dependent mechanism, likely involving JNK signaling.
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Affiliation(s)
- Mike R Visetsouk
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53201, USA
| | - Elizabeth J Falat
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53201, USA
| | - Ryan J Garde
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53201, USA
| | - Jennifer L Wendlick
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53201, USA
| | - Jennifer H Gutzman
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, 53201, USA
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59
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Acharya BR, Nestor-Bergmann A, Liang X, Gupta S, Duszyc K, Gauquelin E, Gomez GA, Budnar S, Marcq P, Jensen OE, Bryant Z, Yap AS. A Mechanosensitive RhoA Pathway that Protects Epithelia against Acute Tensile Stress. Dev Cell 2018; 47:439-452.e6. [PMID: 30318244 DOI: 10.1016/j.devcel.2018.09.016] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/16/2018] [Accepted: 09/15/2018] [Indexed: 12/22/2022]
Abstract
Adherens junctions are tensile structures that couple epithelial cells together. Junctional tension can arise from cell-intrinsic application of contractility or from the cell-extrinsic forces of tissue movement. Here, we report a mechanosensitive signaling pathway that activates RhoA at adherens junctions to preserve epithelial integrity in response to acute tensile stress. We identify Myosin VI as the force sensor, whose association with E-cadherin is enhanced when junctional tension is increased by mechanical monolayer stress. Myosin VI promotes recruitment of the heterotrimeric Gα12 protein to E-cadherin, where it signals for p114 RhoGEF to activate RhoA. Despite its potential to stimulate junctional actomyosin and further increase contractility, tension-activated RhoA signaling is necessary to preserve epithelial integrity. This is explained by an increase in tensile strength, especially at the multicellular vertices of junctions, that is due to mDia1-mediated actin assembly.
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Affiliation(s)
- Bipul R Acharya
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Alexander Nestor-Bergmann
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Xuan Liang
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Shafali Gupta
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Kinga Duszyc
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Estelle Gauquelin
- Institut Jacques Monod, CNRS, UMR 7592, Universite Paris Diderot, Sorbonne Paris Cité, Paris 75205, France
| | - Guillermo A Gomez
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Srikanth Budnar
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Philippe Marcq
- Physico Chimie Curie, Institut Curie, Sorbonne Universite, PSL Research University, Paris and CNRS UMR 168, Paris 75005, France
| | - Oliver E Jensen
- School of Mathematics, University of Manchester, Manchester M13 9PL, UK
| | - Zev Bryant
- Department of Bioengineering, Stanford University and Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alpha S Yap
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
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60
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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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61
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Sun Z, Toyama Y. Three-dimensional forces beyond actomyosin contraction: lessons from fly epithelial deformation. Curr Opin Genet Dev 2018; 51:96-102. [PMID: 30216753 DOI: 10.1016/j.gde.2018.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 10/28/2022]
Abstract
Epithelium undergoes complex deformations during morphogenesis. Many of these deformations rely on the remodelling of apical cell junctions by actomyosin-based contractile force and this has been a major research interest for many years. Recent studies have shown that cells can use additional mechanisms that are not directly driven by actomyosin contractility to alter cell shape and movement, in three-dimensional (3D) space and time. In this review, we focus on a number of these mechanisms, including basolateral cellular protrusion, lateral shift of cell polarity, cytoplasmic flow, regulation of cell volume, and force transmission between cell-cell adhesion and cell-extracellular matrix adhesion, and describe how they underlie Drosophila epithelia deformations.
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Affiliation(s)
- Zijun Sun
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore 117411, Singapore
| | - Yusuke Toyama
- Mechanobiology Institute, National University of Singapore, T-Lab, 5A Engineering Drive 1, Singapore 117411, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
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62
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Yevick HG, Martin AC. Quantitative analysis of cell shape and the cytoskeleton in developmental biology. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2018; 7:e333. [PMID: 30168893 DOI: 10.1002/wdev.333] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/10/2018] [Accepted: 07/25/2018] [Indexed: 11/08/2022]
Abstract
Computational approaches that enable quantification of microscopy data have revolutionized the field of developmental biology. Due to its inherent complexity, elucidating mechanisms of development requires sophisticated analysis of the structure, shape, and kinetics of cellular processes. This need has prompted the creation of numerous techniques to visualize, quantify, and merge microscopy data. These approaches have defined the order and structure of developmental events, thus, providing insight into the mechanisms that drive them. This review describes current computational approaches that are being used to answer developmental questions related to morphogenesis and describe how these approaches have impacted the field. Our intent is not to comprehensively review techniques, but to highlight examples of how different approaches have impacted our understanding of development. Specifically, we focus on methods to quantify cell shape and cytoskeleton structure and dynamics in developing tissues. Finally, we speculate on where the future of computational analysis in developmental biology might be headed. This article is categorized under: Technologies > Analysis of Cell, Tissue, and Animal Phenotypes Early Embryonic Development > Gastrulation and Neurulation Early Embryonic Development > Development to the Basic Body Plan.
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Affiliation(s)
- Hannah G Yevick
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
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63
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Peters KA, Detmar E, Sepulveda L, Del Valle C, Valsquier R, Ritz A, Rogers SL, Applewhite DA. A Cell-based Assay to Investigate Non-muscle Myosin II Contractility via the Folded-gastrulation Signaling Pathway in Drosophila S2R+ Cells. J Vis Exp 2018. [PMID: 30176023 PMCID: PMC6128210 DOI: 10.3791/58325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have developed a cell-based assay using Drosophila cells that recapitulates apical constriction initiated by folded gastrulation (Fog), a secreted epithelial morphogen. In this assay, Fog is used as an agonist to activate Rho through a signaling cascade that includes a G-protein-coupled receptor (Mist), a Gα12/13 protein (Concertina/Cta), and a PDZ-domain-containing guanine nucleotide exchange factor (RhoGEF2). Fog signaling results in the rapid and dramatic reorganization of the actin cytoskeleton to form a contractile purse string. Soluble Fog is collected from a stable cell line and applied ectopically to S2R+ cells, leading to morphological changes like apical constriction, a process observed during developmental processes such as gastrulation. This assay is amenable to high-throughput screening and, using RNAi, can facilitate the identification of additional genes involved in this pathway.
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Affiliation(s)
- Kimberly A Peters
- Department of Biology, The University of North Carolina at Chapel Hill
| | - Elizabeth Detmar
- Department of Biology, The University of North Carolina at Chapel Hill
| | | | | | | | | | - Stephen L Rogers
- Department of Biology, The University of North Carolina at Chapel Hill; Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill; Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill;
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64
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Herrera-Perez RM, Kasza KE. Biophysical control of the cell rearrangements and cell shape changes that build epithelial tissues. Curr Opin Genet Dev 2018; 51:88-95. [DOI: 10.1016/j.gde.2018.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/22/2018] [Accepted: 07/16/2018] [Indexed: 11/26/2022]
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65
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López-Escobar B, Caro-Vega JM, Vijayraghavan DS, Plageman TF, Sanchez-Alcazar JA, Moreno RC, Savery D, Márquez-Rivas J, Davidson LA, Ybot-González P. The non-canonical Wnt-PCP pathway shapes the mouse caudal neural plate. Development 2018; 145:dev.157487. [PMID: 29636380 DOI: 10.1242/dev.157487] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 04/03/2018] [Indexed: 01/03/2023]
Abstract
The last stage of neural tube (NT) formation involves closure of the caudal neural plate (NP), an embryonic structure formed by neuromesodermal progenitors and newly differentiated cells that becomes incorporated into the NT. Here, we show in mouse that, as cell specification progresses, neuromesodermal progenitors and their progeny undergo significant changes in shape prior to their incorporation into the NT. The caudo-rostral progression towards differentiation is coupled to a gradual reliance on a unique combination of complex mechanisms that drive tissue folding, involving pulses of apical actomyosin contraction and planar polarised cell rearrangements, all of which are regulated by the Wnt-PCP pathway. Indeed, when this pathway is disrupted, either chemically or genetically, the polarisation and morphology of cells within the entire caudal NP is disturbed, producing delays in NT closure. The most severe disruptions of this pathway prevent caudal NT closure and result in spina bifida. In addition, a decrease in Vangl2 gene dosage also appears to promote more rapid progression towards a neural fate, but not the specification of more neural cells.
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Affiliation(s)
- Beatriz López-Escobar
- Grupo de Neurodesarrollo, Hospital Universitario Virgen del Rocio/Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla 41013, Spain
| | - José Manuel Caro-Vega
- Grupo de Neurodesarrollo, Hospital Universitario Virgen del Rocio/Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla 41013, Spain
| | | | | | - José A Sanchez-Alcazar
- Centro Andaluz de Biología del Desarrollo (CABD), and CIBERER, Instituto de Salud Carlos III, Universidad Pablo de Olavide-CSIC, Sevilla 41013, Spain
| | - Roberto Carlos Moreno
- Grupo de Neurodesarrollo, Hospital Universitario Virgen del Rocio/Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla 41013, Spain
| | - Dawn Savery
- Newlife Birth Defects Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Javier Márquez-Rivas
- Unidad de Gestión Clínica de Neurocirugía, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla 41013, Spain
| | - Lance A Davidson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Patricia Ybot-González
- Grupo de Neurodesarrollo, Hospital Universitario Virgen del Rocio/Instituto de Biomedicina de Sevilla (IBIS)/CSIC/Universidad de Sevilla, Sevilla 41013, Spain .,Unidad de Gestión Clínica de Neurología y Neurofisiología, Hospital Universitario Virgen Macarena, Sevilla 41009, Spain
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66
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A biochemical network controlling basal myosin oscillation. Nat Commun 2018; 9:1210. [PMID: 29572440 PMCID: PMC5865161 DOI: 10.1038/s41467-018-03574-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 02/20/2018] [Indexed: 01/23/2023] Open
Abstract
The actomyosin cytoskeleton, a key stress-producing unit in epithelial cells, oscillates spontaneously in a wide variety of systems. Although much of the signal cascade regulating myosin activity has been characterized, the origin of such oscillatory behavior is still unclear. Here, we show that basal myosin II oscillation in Drosophila ovarian epithelium is not controlled by actomyosin cortical tension, but instead relies on a biochemical oscillator involving ROCK and myosin phosphatase. Key to this oscillation is a diffusive ROCK flow, linking junctional Rho1 to medial actomyosin cortex, and dynamically maintained by a self-activation loop reliant on ROCK kinase activity. In response to the resulting myosin II recruitment, myosin phosphatase is locally enriched and shuts off ROCK and myosin II signals. Coupling Drosophila genetics, live imaging, modeling, and optogenetics, we uncover an intrinsic biochemical oscillator at the core of myosin II regulatory network, shedding light on the spatio-temporal dynamics of force generation. The actomyosin cytoskeleton is known to spontaneously oscillate in many systems but the mechanism of this behavior is not clear. Here Qin et al. define a signaling network involving a ROCK-dependent self-activation loop and recruitment of myosin II to the cortex, followed by a local accumulation of myosin phosphatase that shuts off the signal.
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67
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Curran S, Strandkvist C, Bathmann J, de Gennes M, Kabla A, Salbreux G, Baum B. Myosin II Controls Junction Fluctuations to Guide Epithelial Tissue Ordering. Dev Cell 2017; 43:480-492.e6. [PMID: 29107560 PMCID: PMC5703647 DOI: 10.1016/j.devcel.2017.09.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 07/24/2017] [Accepted: 09/22/2017] [Indexed: 11/24/2022]
Abstract
Under conditions of homeostasis, dynamic changes in the length of individual adherens junctions (AJs) provide epithelia with the fluidity required to maintain tissue integrity in the face of intrinsic and extrinsic forces. While the contribution of AJ remodeling to developmental morphogenesis has been intensively studied, less is known about AJ dynamics in other circumstances. Here, we study AJ dynamics in an epithelium that undergoes a gradual increase in packing order, without concomitant large-scale changes in tissue size or shape. We find that neighbor exchange events are driven by stochastic fluctuations in junction length, regulated in part by junctional actomyosin. In this context, the developmental increase of isotropic junctional actomyosin reduces the rate of neighbor exchange, contributing to tissue order. We propose a model in which the local variance in tension between junctions determines whether actomyosin-based forces will inhibit or drive the topological transitions that either refine or deform a tissue.
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Affiliation(s)
- Scott Curran
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Charlotte Strandkvist
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Jasper Bathmann
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Marc de Gennes
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Alexandre Kabla
- Department of Engineering, University of Cambridge, Cambridge CB2 OQH, UK
| | - Guillaume Salbreux
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK.
| | - Buzz Baum
- Medical Research Council - Laboratory of Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK.
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68
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Chanet S, Sharan R, Khan Z, Martin AC. Myosin 2-Induced Mitotic Rounding Enables Columnar Epithelial Cells to Interpret Cortical Spindle Positioning Cues. Curr Biol 2017; 27:3350-3358.e3. [DOI: 10.1016/j.cub.2017.09.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/29/2017] [Accepted: 09/19/2017] [Indexed: 01/27/2023]
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69
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Actomyosin pulsation and flows in an active elastomer with turnover and network remodeling. Nat Commun 2017; 8:1121. [PMID: 29066711 PMCID: PMC5783953 DOI: 10.1038/s41467-017-01130-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 08/22/2017] [Indexed: 02/03/2023] Open
Abstract
Tissue remodeling requires cell shape changes associated with pulsation and flow of the actomyosin cytoskeleton. Here we describe the hydrodynamics of actomyosin as a confined active elastomer with turnover of its components. Our treatment is adapted to describe the diversity of contractile dynamical regimes observed in vivo. When myosin-induced contractile stresses are low, the deformations of the active elastomer are affine and exhibit spontaneous oscillations, propagating waves, contractile collapse and spatiotemporal chaos. We study the nucleation, growth and coalescence of actomyosin-dense regions that, beyond a threshold, spontaneously move as a spatially localized traveling front. Large myosin-induced contractile stresses lead to nonaffine deformations due to enhanced actin and crosslinker turnover. This results in a transient actin network that is constantly remodeling and naturally accommodates intranetwork flows of the actomyosin-dense regions. We verify many predictions of our study in Drosophila embryonic epithelial cells undergoing neighbor exchange during germband extension. Tissue remodeling involves substantial involvement of the contractile actomyosin cytoskeleton. Here the authors model the spatiotemporal evolution of actomyosin densities during Drosophila germband extension and find affine and nonaffine deformations that depend on the magnitude of local contractile stress.
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70
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Alvarado J, Sheinman M, Sharma A, MacKintosh FC, Koenderink GH. Force percolation of contractile active gels. SOFT MATTER 2017; 13:5624-5644. [PMID: 28812094 DOI: 10.1039/c7sm00834a] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Living systems provide a paradigmatic example of active soft matter. Cells and tissues comprise viscoelastic materials that exert forces and can actively change shape. This strikingly autonomous behavior is powered by the cytoskeleton, an active gel of semiflexible filaments, crosslinks, and molecular motors inside cells. Although individual motors are only a few nm in size and exert minute forces of a few pN, cells spatially integrate the activity of an ensemble of motors to produce larger contractile forces (∼nN and greater) on cellular, tissue, and organismal length scales. Here we review experimental and theoretical studies on contractile active gels composed of actin filaments and myosin motors. Unlike other active soft matter systems, which tend to form ordered patterns, actin-myosin systems exhibit a generic tendency to contract. Experimental studies of reconstituted actin-myosin model systems have long suggested that a mechanical interplay between motor activity and the network's connectivity governs this contractile behavior. Recent theoretical models indicate that this interplay can be understood in terms of percolation models, extended to include effects of motor activity on the network connectivity. Based on concepts from percolation theory, we propose a state diagram that unites a large body of experimental observations. This framework provides valuable insights into the mechanisms that drive cellular shape changes and also provides design principles for synthetic active materials.
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Affiliation(s)
- José Alvarado
- Systems Biophysics Department, AMOLF, 1098 XG Amsterdam, The Netherlands.
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71
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Tsankova A, Pham TT, Garcia DS, Otte F, Cabernard C. Cell Polarity Regulates Biased Myosin Activity and Dynamics during Asymmetric Cell Division via Drosophila Rho Kinase and Protein Kinase N. Dev Cell 2017; 42:143-155.e5. [PMID: 28712722 DOI: 10.1016/j.devcel.2017.06.012] [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: 09/06/2016] [Revised: 02/06/2017] [Accepted: 06/14/2017] [Indexed: 12/18/2022]
Abstract
Cell and tissue morphogenesis depends on the correct regulation of non-muscle Myosin II, but how this motor protein is spatiotemporally controlled is incompletely understood. Here, we show that in asymmetrically dividing Drosophila neural stem cells, cell intrinsic polarity cues provide spatial and temporal information to regulate biased Myosin activity. Using live cell imaging and a genetically encoded Myosin activity sensor, we found that Drosophila Rho kinase (Rok) enriches for activated Myosin on the neuroblast cortex prior to nuclear envelope breakdown (NEB). After NEB, the conserved polarity protein Partner of Inscuteable (Pins) sequentially enriches Rok and Protein Kinase N (Pkn) on the apical neuroblast cortex. Our data suggest that apical Rok first increases phospho-Myosin, followed by Pkn-mediated Myosin downregulation, possibly through Rok inhibition. We propose that polarity-induced spatiotemporal control of Rok and Pkn is important for unequal cortical expansion, ensuring correct cleavage furrow positioning and the establishment of physical asymmetry.
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Affiliation(s)
- Anna Tsankova
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Tri Thanh Pham
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland; Department of Biology, University of Washington, 24 Kinkaid Hall, Seattle, WA 98105, USA
| | | | - Fabian Otte
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Clemens Cabernard
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland; Department of Biology, University of Washington, 24 Kinkaid Hall, Seattle, WA 98105, USA.
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72
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Ly D, Resch E, Ordiway G, DiNardo S. Asymmetrically deployed actomyosin-based contractility generates a boundary between developing leg segments in Drosophila. Dev Biol 2017; 429:165-176. [PMID: 28689737 DOI: 10.1016/j.ydbio.2017.06.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/22/2017] [Accepted: 06/27/2017] [Indexed: 02/02/2023]
Abstract
The formation of complex tissues from simple epithelial sheets requires the regional subdivision of the developing tissue. This is initially accomplished by a sequence of gene regulatory hierarchies that set up distinct fates within adjacent territories, and rely on cross-regulatory interactions to do so. However, once adjacent territories are established, cells that confront one another across territorial boundaries must actively participate in maintaining separation from each other. Classically, it was assumed that adhesive differences would be a primary means of sorting cells to their respective territories. Yet it is becoming clear that no single, simple mechanism is at play. In the few instances studied, an emergent theme along developmental boundaries is the generation of asymmetry in cell mechanical properties. The repertoire of ways in which cells might establish and then put mechanical asymmetry to work is not fully appreciated since only a few boundaries have been molecularly studied. Here, we characterize once such boundary in the develop leg epithelium of Drosophila. The region of the pretarsus / tarsus is a known gene expression boundary that also exhibits a lineage restriction (Sakurai et al., 2007). We now show that the interface comprising this boundary is strikingly aligned compared to other cell interfaces across the disk. The boundary also exhibits an asymmetry for both Myosin II accumulation as well as one of its activators, Rho Kinase. Furthermore, the enrichment correlates with increased mechanical tension across that interface, and that tension is Rho Kinase-dependent. Lastly, interfering with actomyosin contractility, either by depletion of myosin heavy chain or expression of a phosphomimetic variant of regulatory light chain causes defects in alignment of the interfaces. These data suggest strongly that mechanical asymmetries are key in establishing and maintaining this developmental boundary.
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Affiliation(s)
- Dan Ly
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Erin Resch
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - George Ordiway
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Stephen DiNardo
- Department of Cell and Developmental Biology, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, United States
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73
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An Y, Xue G, Shaobo Y, Mingxi D, Zhou X, Yu W, Ishibashi T, Zhang L, Yan Y. Apical constriction is driven by a pulsatile apical myosin network in delaminating Drosophila neuroblasts. Development 2017; 144:2153-2164. [PMID: 28506995 DOI: 10.1242/dev.150763] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 04/28/2017] [Indexed: 01/07/2023]
Abstract
Cell delamination is a conserved morphogenetic process important for the generation of cell diversity and maintenance of tissue homeostasis. Here, we used Drosophila embryonic neuroblasts as a model to study the apical constriction process during cell delamination. We observe dynamic myosin signals both around the cell adherens junctions and underneath the cell apical surface in the neuroectoderm. On the cell apical cortex, the nonjunctional myosin forms flows and pulses, which are termed medial myosin pulses. Quantitative differences in medial myosin pulse intensity and frequency are crucial to distinguish delaminating neuroblasts from their neighbors. Inhibition of medial myosin pulses blocks delamination. The fate of a neuroblast is set apart from that of its neighbors by Notch signaling-mediated lateral inhibition. When we inhibit Notch signaling activity in the embryo, we observe that small clusters of cells undergo apical constriction and display an abnormal apical myosin pattern. Together, these results demonstrate that a contractile actomyosin network across the apical cell surface is organized to drive apical constriction in delaminating neuroblasts.
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Affiliation(s)
- Yanru An
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Guosheng Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yang Shaobo
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Deng Mingxi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiaowei Zhou
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Weichuan Yu
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Toyotaka Ishibashi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Lei Zhang
- Beijing International Center for Mathematical Research, Peking University, Beijing, 100871, China .,Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Yan Yan
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China .,Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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74
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Chanet S, Miller CJ, Vaishnav ED, Ermentrout B, Davidson LA, Martin AC. Actomyosin meshwork mechanosensing enables tissue shape to orient cell force. Nat Commun 2017; 8:15014. [PMID: 28504247 PMCID: PMC5440693 DOI: 10.1038/ncomms15014] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 02/17/2017] [Indexed: 12/23/2022] Open
Abstract
Sculpting organism shape requires that cells produce forces with proper directionality. Thus, it is critical to understand how cells orient the cytoskeleton to produce forces that deform tissues. During Drosophila gastrulation, actomyosin contraction in ventral cells generates a long, narrow epithelial furrow, termed the ventral furrow, in which actomyosin fibres and tension are directed along the length of the furrow. Using a combination of genetic and mechanical perturbations that alter tissue shape, we demonstrate that geometrical and mechanical constraints act as cues to orient the cytoskeleton and tension during ventral furrow formation. We developed an in silico model of two-dimensional actomyosin meshwork contraction, demonstrating that actomyosin meshworks exhibit an inherent force orienting mechanism in response to mechanical constraints. Together, our in vivo and in silico data provide a framework for understanding how cells orient force generation, establishing a role for geometrical and mechanical patterning of force production in tissues. Large-scale tissue reorganization requires the generation of directional tension, which requires orientation of the cytoskeleton. Here Chanet et al. alter tissue shape and tension in the Drosophila embryo to show that geometric and mechanical constraints act as cues to orient the cytoskeleton and tension.
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Affiliation(s)
- Soline Chanet
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Callie J Miller
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Eeshit Dhaval Vaishnav
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Bard Ermentrout
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Lance A Davidson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.,Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.,Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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75
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Heer NC, Miller PW, Chanet S, Stoop N, Dunkel J, Martin AC. Actomyosin-based tissue folding requires a multicellular myosin gradient. Development 2017; 144:1876-1886. [PMID: 28432215 DOI: 10.1242/dev.146761] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 04/10/2017] [Indexed: 12/21/2022]
Abstract
Tissue folding promotes three-dimensional (3D) form during development. In many cases, folding is associated with myosin accumulation at the apical surface of epithelial cells, as seen in the vertebrate neural tube and the Drosophila ventral furrow. This type of folding is characterized by constriction of apical cell surfaces, and the resulting cell shape change is thought to cause tissue folding. Here, we use quantitative microscopy to measure the pattern of transcription, signaling, myosin activation and cell shape in the Drosophila mesoderm. We found that cells within the ventral domain accumulate different amounts of active apical non-muscle myosin 2 depending on the distance from the ventral midline. This gradient in active myosin depends on a newly quantified gradient in upstream signaling proteins. A 3D continuum model of the embryo with induced contractility demonstrates that contractility gradients, but not contractility per se, promote changes to surface curvature and folding. As predicted by the model, experimental broadening of the myosin domain in vivo disrupts tissue curvature where myosin is uniform. Our data argue that apical contractility gradients are important for tissue folding.
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Affiliation(s)
- Natalie C Heer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Pearson W Miller
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Soline Chanet
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Norbert Stoop
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jörn Dunkel
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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76
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Qin X, Park BO, Liu J, Chen B, Choesmel-Cadamuro V, Belguise K, Heo WD, Wang X. Cell-matrix adhesion and cell-cell adhesion differentially control basal myosin oscillation and Drosophila egg chamber elongation. Nat Commun 2017; 8:14708. [PMID: 28406187 PMCID: PMC5399299 DOI: 10.1038/ncomms14708] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/19/2017] [Indexed: 01/22/2023] Open
Abstract
Pulsatile actomyosin contractility, important in tissue morphogenesis, has been studied mainly in apical but less in basal domains. Basal myosin oscillation underlying egg chamber elongation is regulated by both cell–matrix and cell–cell adhesions. However, the mechanism by which these two adhesions govern basal myosin oscillation and tissue elongation is unknown. Here we demonstrate that cell–matrix adhesion positively regulates basal junctional Rho1 activity and medio-basal ROCK and myosin activities, thus strongly controlling tissue elongation. Differently, cell–cell adhesion governs basal myosin oscillation through controlling medio-basal distributions of both ROCK and myosin signals, which are related to the spatial limitations of cell–matrix adhesion and stress fibres. Contrary to cell–matrix adhesion, cell–cell adhesion weakly affects tissue elongation. In vivo optogenetic protein inhibition spatiotemporally confirms the different effects of these two adhesions on basal myosin oscillation. This study highlights the activity and distribution controls of basal myosin contractility mediated by cell–matrix and cell–cell adhesions, respectively, during tissue morphogenesis. Pulsatile actomyosin contractility during tissue morphogenesis has been mainly studied in apical domains but less is known about the contribution of the basal domain. Here the authors show differential influence of cell-matrix and cell-cell adhesions in regulating oscillations and tissue elongation.
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Affiliation(s)
- Xiang Qin
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Byung Ouk Park
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Jiaying Liu
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Bing Chen
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France.,Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Valerie Choesmel-Cadamuro
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Karine Belguise
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Won Do Heo
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Xiaobo Wang
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
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77
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Coravos JS, Mason FM, Martin AC. Actomyosin Pulsing in Tissue Integrity Maintenance during Morphogenesis. Trends Cell Biol 2017; 27:276-283. [PMID: 27989655 PMCID: PMC5367975 DOI: 10.1016/j.tcb.2016.11.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 11/19/2022]
Abstract
The actomyosin cytoskeleton is responsible for many changes in cell and tissue shape. For a long time, the actomyosin cytoskeleton has been known to exhibit dynamic contractile behavior. Recently, discrete actomyosin assembly/disassembly cycles have also been observed in cells. These so-called actomyosin pulses have been observed in a variety of contexts, including cell polarization and division, and in epithelia, where they occur during tissue contraction, folding, and extension. In epithelia, evidence suggests that actomyosin pulsing, and more generally, actomyosin turnover, is required to maintain tissue integrity during contractile processes. This review explores possible functions for pulsing in the many instances during which pulsing has been observed, and also highlights proposed molecular mechanisms that drive pulsing.
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Affiliation(s)
- Jonathan S Coravos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Frank M Mason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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78
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Simões S, Oh Y, Wang MFZ, Fernandez-Gonzalez R, Tepass U. Myosin II promotes the anisotropic loss of the apical domain during Drosophila neuroblast ingression. J Cell Biol 2017; 216:1387-1404. [PMID: 28363972 PMCID: PMC5412560 DOI: 10.1083/jcb.201608038] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/15/2016] [Accepted: 02/14/2017] [Indexed: 01/06/2023] Open
Abstract
Drosophila neural stem cells, or neuroblasts, ingress from the neuroepithelium in an EMT-like process, during which the apical cell domain is lost. Apical constriction of neuroblasts and the serial loss of cell–cell contacts require periodic pulses of actomyosin that cause progressively stronger ratcheted contractions of the neuroblast apical cortex. Epithelial–mesenchymal transitions play key roles in development and cancer and entail the loss of epithelial polarity and cell adhesion. In this study, we use quantitative live imaging of ingressing neuroblasts (NBs) in Drosophila melanogaster embryos to assess apical domain loss and junctional disassembly. Ingression is independent of the Snail family of transcriptional repressors and down-regulation of Drosophila E-cadherin (DEcad) transcription. Instead, the posttranscriptionally regulated decrease in DEcad coincides with the reduction of cell contact length and depends on tension anisotropy between NBs and their neighbors. A major driver of apical constriction and junctional disassembly are periodic pulses of junctional and medial myosin II that result in progressively stronger cortical contractions during ingression. Effective contractions require the molecular coupling between myosin and junctions and apical relaxation of neighboring cells. Moreover, planar polarization of myosin leads to the loss of anterior–posterior junctions before the loss of dorsal–ventral junctions. We conclude that planar-polarized dynamic actomyosin networks drive apical constriction and the anisotropic loss of cell contacts during NB ingression.
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Affiliation(s)
- Sérgio Simões
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Youjin Oh
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Michael F Z Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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79
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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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80
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Kobb AB, Zulueta-Coarasa T, Fernandez-Gonzalez R. Tension regulates myosin dynamics during Drosophila embryonic wound repair. J Cell Sci 2017; 130:689-696. [DOI: 10.1242/jcs.196139] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/03/2017] [Indexed: 12/14/2022] Open
Abstract
ABSTRACT
Embryos repair epithelial wounds rapidly in a process driven by collective cell movements. Upon wounding, actin and the molecular motor non-muscle myosin II are redistributed in the cells adjacent to the wound, forming a supracellular purse string around the lesion. Purse string contraction coordinates cell movements and drives rapid wound closure. By using fluorescence recovery after photobleaching in Drosophila embryos, we found that myosin turns over as the purse string contracts. Myosin turnover at the purse string was slower than in other actomyosin networks that had a lower level of contractility. Mathematical modelling suggested that myosin assembly and disassembly rates were both reduced by tension at the wound edge. We used laser ablation to show that tension at the purse string increased as wound closure progressed, and that the increase in tension was associated with reduced myosin turnover. Reducing purse string tension by laser-mediated severing resulted in increased turnover and loss of myosin. Finally, myosin motor activity was necessary for its stabilization around the wound and for rapid wound closure. Our results indicate that mechanical forces regulate myosin dynamics during embryonic wound repair.
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Affiliation(s)
- Anna B. Kobb
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
| | - Teresa Zulueta-Coarasa
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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81
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From morphogen to morphogenesis and back. Nature 2017; 541:311-320. [DOI: 10.1038/nature21348] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 11/18/2016] [Indexed: 12/11/2022]
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82
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Baird MA, Billington N, Wang A, Adelstein RS, Sellers JR, Fischer RS, Waterman CM. Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells. Mol Biol Cell 2017; 28:240-251. [PMID: 27881665 PMCID: PMC5231893 DOI: 10.1091/mbc.e16-05-0335] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 11/02/2016] [Accepted: 11/18/2016] [Indexed: 01/03/2023] Open
Abstract
The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A "pulses" occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell-cell or cell-ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase- or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells.
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Affiliation(s)
- Michelle A Baird
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Neil Billington
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Aibing Wang
- Genetics and Developmental Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
- College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128, China
| | - Robert S Adelstein
- Genetics and Developmental Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - James R Sellers
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Robert S Fischer
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Clare M Waterman
- Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
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83
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Vasquez CG, Heissler SM, Billington N, Sellers JR, Martin AC. Drosophila non-muscle myosin II motor activity determines the rate of tissue folding. eLife 2016; 5. [PMID: 28035903 PMCID: PMC5201417 DOI: 10.7554/elife.20828] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 12/08/2016] [Indexed: 12/15/2022] Open
Abstract
Non-muscle cell contractility is critical for tissues to adopt shape changes. Although, the non-muscle myosin II holoenzyme (myosin) is a molecular motor that powers contraction of actin cytoskeleton networks, recent studies have questioned the importance of myosin motor activity cell and tissue shape changes. Here, combining the biochemical analysis of enzymatic and motile properties for purified myosin mutants with in vivo measurements of apical constriction for the same mutants, we show that in vivo constriction rate scales with myosin motor activity. We show that so-called phosphomimetic mutants of the Drosophila regulatory light chain (RLC) do not mimic the phosphorylated RLC state in vitro. The defect in the myosin motor activity in these mutants is evident in developing Drosophila embryos where tissue recoil following laser ablation is decreased compared to wild-type tissue. Overall, our data highlights that myosin activity is required for rapid cell contraction and tissue folding in developing Drosophila embryos. DOI:http://dx.doi.org/10.7554/eLife.20828.001
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Affiliation(s)
- Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Neil Billington
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
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84
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Duque J, Gorfinkiel N. Integration of actomyosin contractility with cell-cell adhesion during dorsal closure. Development 2016; 143:4676-4686. [PMID: 27836966 DOI: 10.1242/dev.136127] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 10/27/2016] [Indexed: 02/01/2023]
Abstract
In this work, we combine genetic perturbation, time-lapse imaging and quantitative image analysis to investigate how pulsatile actomyosin contractility drives cell oscillations, apical cell contraction and tissue closure during morphogenesis of the amnioserosa, the main force-generating tissue during the dorsal closure in Drosophila We show that Myosin activity determines the oscillatory and contractile behaviour of amnioserosa cells. Reducing Myosin activity prevents cell shape oscillations and reduces cell contractility. By contrast, increasing Myosin activity increases the amplitude of cell shape oscillations and the time cells spend in the contracted phase relative to the expanded phase during an oscillatory cycle, promoting cell contractility and tissue closure. Furthermore, we show that in AS cells, Rok controls Myosin foci formation and Mbs regulates not only Myosin phosphorylation but also adhesion dynamics through control of Moesin phosphorylation, showing that Mbs coordinates actomyosin contractility with cell-cell adhesion during amnioserosa morphogenesis.
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Affiliation(s)
- Julia Duque
- Centro de Biología Molecular 'Severo Ochoa', CSIC-UAM, Cantoblanco, Madrid 28049, Spain
| | - Nicole Gorfinkiel
- Centro de Biología Molecular 'Severo Ochoa', CSIC-UAM, Cantoblanco, Madrid 28049, Spain
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85
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Jurado J, de Navascués J, Gorfinkiel N. α-Catenin stabilises Cadherin-Catenin complexes and modulates actomyosin dynamics to allow pulsatile apical contraction. J Cell Sci 2016; 129:4496-4508. [PMID: 27831494 DOI: 10.1242/jcs.193268] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/02/2016] [Indexed: 01/07/2023] Open
Abstract
We have investigated how cell contractility and adhesion are functionally integrated during epithelial morphogenesis. To this end, we have analysed the role of α-Catenin, a key molecule linking E-Cadherin-based adhesion and the actomyosin cytoskeleton, during Drosophila embryonic dorsal closure, by studying a newly developed allelic series. We find that α-Catenin regulates pulsatile apical contraction in the amnioserosa, the main force-generating tissue driving closure of the embryonic epidermis. α-Catenin controls actomyosin dynamics by stabilising and promoting the formation of actomyosin foci, and also stabilises DE-Cadherin (Drosophila E-Cadherin, also known as Shotgun) at the cell membrane, suggesting that medioapical actomyosin contractility regulates junction stability. Furthermore, we uncover a genetic interaction between α-Catenin and Vinculin, and a tension-dependent recruitment of Vinculin to amniosersoa apical cell membranes, suggesting the existence of a mechano-sensitive module operating in this tissue.
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Affiliation(s)
- Jaime Jurado
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, Cantoblanco, Madrid 28049, Spain
| | - Joaquín de Navascués
- European Cancer Stem Cell Research Institute, School of Biosciences, Cardiff University, Cardiff CF24 4HQ, UK
| | - Nicole Gorfinkiel
- Centro de Biología Molecular "Severo Ochoa", CSIC-UAM, Cantoblanco, Madrid 28049, Spain
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86
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Coravos JS, Martin AC. Apical Sarcomere-like Actomyosin Contracts Nonmuscle Drosophila Epithelial Cells. Dev Cell 2016; 39:346-358. [PMID: 27773487 PMCID: PMC5102765 DOI: 10.1016/j.devcel.2016.09.023] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 07/21/2016] [Accepted: 09/25/2016] [Indexed: 11/17/2022]
Abstract
Actomyosin networks generate contractile force that changes cell and tissue shape. In muscle cells, actin filaments and myosin II appear in a polarized structure called a sarcomere, in which myosin II is localized in the center. Nonmuscle cortical actomyosin networks are thought to contract when nonmuscle myosin II (myosin) is activated throughout a mixed-polarity actin network. Here, we identified a mutant version of the myosin-activating kinase, ROCK, that localizes diffusely, rather than centrally, in epithelial cell apices. Surprisingly, this mutant inhibits constriction, suggesting that centrally localized apical ROCK/myosin activity promotes contraction. We determined actin cytoskeletal polarity by developing a barbed end incorporation assay for Drosophila embryos, which revealed barbed end enrichment at junctions. Our results demonstrate that epithelial cells contract with a spatially organized apical actomyosin cortex, involving a polarized actin cytoskeleton and centrally positioned myosin, with cell-scale order that resembles a muscle sarcomere.
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Affiliation(s)
- Jonathan S Coravos
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02142, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02142, USA.
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87
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Xue Z, Sokac AM. -Back-to-back mechanisms drive actomyosin ring closure during Drosophila embryo cleavage. J Cell Biol 2016; 215:335-344. [PMID: 27799369 PMCID: PMC5100295 DOI: 10.1083/jcb.201608025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 10/10/2016] [Indexed: 12/30/2022] Open
Abstract
The mechanisms mediating actomyosin ring contraction during Drosophila cellularization, a developmental division that resembles cytokinesis, are unclear. Xue and Sokac delineate the contribution of cytoskeletal motors and actin-binding proteins to actomyosin ring constriction as Drosophila embryos undergo cleavage. Contraction of actomyosin rings during cytokinesis is typically attributed to actin filaments sliding toward each other via Myosin-2 motor activity. However, rings constrict in some cells in the absence of Myosin-2 activity. Thus, ring closure uses Myosin-2–dependent and –independent mechanisms. But what the Myosin-2–independent mechanisms are, and to what extent they are sufficient to drive closure, remains unclear. During cleavage in Drosophila melanogaster embryos, actomyosin rings constrict in two sequential and mechanistically distinct phases. We show that these phases differ in constriction speed and are genetically and pharmacologically separable. Further, Myosin-2 activity is required for slow constriction in “phase 1” but is largely dispensable for fast constriction in “phase 2,” and F-actin disassembly is only required for fast constriction in phase 2. Switching from phase 1 to phase 2 seemingly relies on the spatial organization of F-actin as controlled by Cofilin, Anillin, and Septin. Our work shows that fly embryos present a singular opportunity to compare separable ring constriction mechanisms, with varying Myosin-2 dependencies, in one cell type and in vivo.
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Affiliation(s)
- Zenghui Xue
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Anna Marie Sokac
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
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88
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Mason FM, Xie S, Vasquez CG, Tworoger M, Martin AC. RhoA GTPase inhibition organizes contraction during epithelial morphogenesis. J Cell Biol 2016; 214:603-17. [PMID: 27551058 PMCID: PMC5004446 DOI: 10.1083/jcb.201603077] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/15/2016] [Indexed: 12/05/2022] Open
Abstract
Mason et al. show that RhoA activity is regulated in space and time by a GEF/GAP module that tunes cell behavior and is required for proper tissue folding and shape during Drosophila morphogenesis. During morphogenesis, contraction of the actomyosin cytoskeleton within individual cells drives cell shape changes that fold tissues. Coordination of cytoskeletal contractility is mediated by regulating RhoA GTPase activity. Guanine nucleotide exchange factors (GEFs) activate and GTPase-activating proteins (GAPs) inhibit RhoA activity. Most studies of tissue folding, including apical constriction, have focused on how RhoA is activated by GEFs to promote cell contractility, with little investigation as to how GAPs may be important. Here, we identify a critical role for a RhoA GAP, Cumberland GAP (C-GAP), which coordinates with a RhoA GEF, RhoGEF2, to organize spatiotemporal contractility during Drosophila melanogaster apical constriction. C-GAP spatially restricts RhoA pathway activity to a central position in the apical cortex. RhoGEF2 pulses precede myosin, and C-GAP is required for pulsation, suggesting that contractile pulses result from RhoA activity cycling. Finally, C-GAP expression level influences the transition from reversible to irreversible cell shape change, which defines the onset of tissue shape change. Our data demonstrate that RhoA activity cycling and modulating the ratio of RhoGEF2 to C-GAP are required for tissue folding.
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Affiliation(s)
- Frank M Mason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Shicong Xie
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Michael Tworoger
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
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89
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Xie S, Mason FM, Martin AC. Loss of Gα12/13 exacerbates apical area dependence of actomyosin contractility. Mol Biol Cell 2016; 27:3526-3536. [PMID: 27489340 PMCID: PMC5221585 DOI: 10.1091/mbc.e16-05-0305] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/27/2016] [Indexed: 01/23/2023] Open
Abstract
Gα12/13 loss causes cells with a larger apical area to constrict later than smaller cells, leading to uncoordinated constriction. Apical area influences actin density, myosin regulation, and E-cadherin levels. Thus Gα12/13 is crucial for the robust initiation of contraction in a tissue in which cells initially have heterogeneous apical areas. During development, coordinated cell shape changes alter tissue shape. In the Drosophila ventral furrow and other epithelia, apical constriction of hundreds of epithelial cells folds the tissue. Genes in the Gα12/13 pathway coordinate collective apical constriction, but the mechanism of coordination is poorly understood. Coupling live-cell imaging with a computational approach to identify contractile events, we discovered that differences in constriction behavior are biased by initial cell shape. Disrupting Gα12/13 exacerbates this relationship. Larger apical area is associated with delayed initiation of contractile pulses, lower apical E-cadherin and F-actin levels, and aberrantly mobile Rho-kinase structures. Our results suggest that loss of Gα12/13 disrupts apical actin cortex organization and pulse initiation in a size-dependent manner. We propose that Gα12/13 robustly organizes the apical cortex despite variation in apical area to ensure the timely initiation of contractile pulses in a tissue with heterogeneity in starting cell shape.
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Affiliation(s)
- Shicong Xie
- Computational and Systems Biology Program, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Frank M Mason
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
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90
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Pfister K, Shook DR, Chang C, Keller R, Skoglund P. Molecular model for force production and transmission during vertebrate gastrulation. Development 2016; 143:715-27. [PMID: 26884399 DOI: 10.1242/dev.128090] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Vertebrate embryos undergo dramatic shape changes at gastrulation that require locally produced and anisotropically applied forces, yet how these forces are produced and transmitted across tissues remains unclear. We show that depletion of myosin regulatory light chain (RLC) levels in the embryo blocks force generation at gastrulation through two distinct mechanisms: destabilizing the myosin II (MII) hexameric complex and inhibiting MII contractility. Molecular dissection of these two mechanisms demonstrates that normal convergence force generation requires MII contractility and we identify a set of molecular phenotypes correlated with both this failure of convergence force generation in explants and of blastopore closure in whole embryos. These include reduced rates of actin movement, alterations in C-cadherin dynamics and a reduction in the number of polarized lamellipodia on intercalating cells. By examining the spatial relationship between C-cadherin and actomyosin we also find evidence for formation of transcellular linear arrays incorporating these proteins that could transmit mediolaterally oriented tensional forces. These data combine to suggest a multistep model to explain how cell intercalation can occur against a force gradient to generate axial extension forces. First, polarized lamellipodia extend mediolaterally and make new C-cadherin-based contacts with neighboring mesodermal cell bodies. Second, lamellipodial flow of actin coalesces into a tension-bearing, MII-contractility-dependent node-and-cable actin network in the cell body cortex. And third, this actomyosin network contracts to generate mediolateral convergence forces in the context of these transcellular arrays.
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Affiliation(s)
- Katherine Pfister
- Biology Department, University of Virginia, Charlottesville, VA 22903, USA
| | - David R Shook
- Biology Department, University of Virginia, Charlottesville, VA 22903, USA
| | - Chenbei Chang
- Department of Cell Biology, University of Alabama, Birmingham, AL 35294, USA
| | - Ray Keller
- Biology Department, University of Virginia, Charlottesville, VA 22903, USA
| | - Paul Skoglund
- Biology Department, University of Virginia, Charlottesville, VA 22903, USA
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91
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Abstract
The myosin holoenzyme is a multimeric protein complex consisting of heavy chains and light chains. Myosin light chains are calmodulin family members which are crucially involved in the mechanoenzymatic function of the myosin holoenzyme. This review examines the diversity of light chains within the myosin superfamily, discusses interactions between the light chain and the myosin heavy chain as well as regulatory and structural functions of the light chain as a subunit of the myosin holoenzyme. It covers aspects of the myosin light chain in the localization of the myosin holoenzyme, protein-protein interactions and light chain binding to non-myosin binding partners. Finally, this review challenges the dogma that myosin regulatory and essential light chain exclusively associate with conventional myosin heavy chains while unconventional myosin heavy chains usually associate with calmodulin.
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Affiliation(s)
- Sarah M Heissler
- a Laboratory of Molecular Physiology; National Heart, Lung, and Blood Institute; National Institutes of Health ; Bethesda , MD USA
| | - James R Sellers
- a Laboratory of Molecular Physiology; National Heart, Lung, and Blood Institute; National Institutes of Health ; Bethesda , MD USA
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92
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Aranjuez G, Burtscher A, Sawant K, Majumder P, McDonald JA. Dynamic myosin activation promotes collective morphology and migration by locally balancing oppositional forces from surrounding tissue. Mol Biol Cell 2016; 27:1898-910. [PMID: 27122602 PMCID: PMC4907723 DOI: 10.1091/mbc.e15-10-0744] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/21/2016] [Indexed: 12/24/2022] Open
Abstract
A challenge for migrating collectives is to respond to physical changes in local environments. Border cells migrate collectively in the Drosophila ovary and require dynamic myosin to maintain their morphology. Border cells elevate active myosin in response to tissue compression. Myosin tension counteracts tissue constraints for collective movement. Migrating cells need to overcome physical constraints from the local microenvironment to navigate their way through tissues. Cells that move collectively have the additional challenge of negotiating complex environments in vivo while maintaining cohesion of the group as a whole. The mechanisms by which collectives maintain a migratory morphology while resisting physical constraints from the surrounding tissue are poorly understood. Drosophila border cells represent a genetic model of collective migration within a cell-dense tissue. Border cells move as a cohesive group of 6−10 cells, traversing a network of large germ line–derived nurse cells within the ovary. Here we show that the border cell cluster is compact and round throughout their entire migration, a shape that is maintained despite the mechanical pressure imposed by the surrounding nurse cells. Nonmuscle myosin II (Myo-II) activity at the cluster periphery becomes elevated in response to increased constriction by nurse cells. Furthermore, the distinctive border cell collective morphology requires highly dynamic and localized enrichment of Myo-II. Thus, activated Myo-II promotes cortical tension at the outer edge of the migrating border cell cluster to resist compressive forces from nurse cells. We propose that dynamic actomyosin tension at the periphery of collectives facilitates their movement through restrictive tissues.
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Affiliation(s)
- George Aranjuez
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Ashley Burtscher
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Ketki Sawant
- Division of Biology, Kansas State University, Manhattan, KS 66506
| | - Pralay Majumder
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Jocelyn A McDonald
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 Division of Biology, Kansas State University, Manhattan, KS 66506
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93
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Fenix AM, Taneja N, Buttler CA, Lewis J, Van Engelenburg SB, Ohi R, Burnette DT. Expansion and concatenation of non-muscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis. Mol Biol Cell 2016; 27:mbc.E15-10-0725. [PMID: 26960797 PMCID: PMC4850034 DOI: 10.1091/mbc.e15-10-0725] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/25/2016] [Accepted: 03/01/2016] [Indexed: 11/19/2022] Open
Abstract
Cell movement and cytokinesis are facilitated by contractile forces generated by the molecular motor, non-muscle myosin II (NMII). NMII molecules form a filament (NMII-F) through interactions of their C-terminal rod domains, positioning groups of N-terminal motor domains on opposite sides. The NMII motors then bind and pull actin filaments toward the NMII-F, thus driving contraction. Inside of crawling cells, NMIIA-Fs form large macromolecular ensembles (i.e., NMIIA-F stacks) but how this occurs is unknown. Here we show NMIIA-F stacks are formed through two non-mutually exclusive mechanisms: expansion and concatenation. During expansion, NMIIA molecules within the NMIIA-F spread out concurrent with addition of new NMIIA molecules. Concatenation occurs when multiple NMIIA-F/NMIIA-F stacks move together and align. We found NMIIA-F stack formation was regulated by both motor-activity and the availability of surrounding actin filaments. Furthermore, our data showed expansion and concatenation also formed the contractile ring in dividing cells. Thus, interphase and mitotic cells share similar mechanisms for creating large contractile units, and these are likely to underlie how other myosin II-based contractile systems are assembled.
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Affiliation(s)
- Aidan M Fenix
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Nilay Taneja
- Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | - John Lewis
- Vanderbilt University School of Medicine, Nashville, TN 37232 Kalamazoo College, Kalamazoo, MI 49008
| | | | - Ryoma Ohi
- Vanderbilt University School of Medicine, Nashville, TN 37232
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94
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Kannan N, Tang VW. Synaptopodin couples epithelial contractility to α-actinin-4-dependent junction maturation. J Cell Biol 2016; 211:407-34. [PMID: 26504173 PMCID: PMC4621826 DOI: 10.1083/jcb.201412003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A novel tension-sensitive junctional protein, synaptopodin, can relay biophysical input from cellular actomyosin contractility to induce biochemical changes at cell–cell contacts, resulting in structural reorganization of the junctional complex and epithelial barrier maturation. The epithelial junction experiences mechanical force exerted by endogenous actomyosin activities and from interactions with neighboring cells. We hypothesize that tension generated at cell–cell adhesive contacts contributes to the maturation and assembly of the junctional complex. To test our hypothesis, we used a hydraulic apparatus that can apply mechanical force to intercellular junction in a confluent monolayer of cells. We found that mechanical force induces α-actinin-4 and actin accumulation at the cell junction in a time- and tension-dependent manner during junction development. Intercellular tension also induces α-actinin-4–dependent recruitment of vinculin to the cell junction. In addition, we have identified a tension-sensitive upstream regulator of α-actinin-4 as synaptopodin. Synaptopodin forms a complex containing α-actinin-4 and β-catenin and interacts with myosin II, indicating that it can physically link adhesion molecules to the cellular contractile apparatus. Synaptopodin depletion prevents junctional accumulation of α-actinin-4, vinculin, and actin. Knockdown of synaptopodin and α-actinin-4 decreases the strength of cell–cell adhesion, reduces the monolayer permeability barrier, and compromises cellular contractility. Our findings underscore the complexity of junction development and implicate a control process via tension-induced sequential incorporation of junctional components.
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Affiliation(s)
- Nivetha Kannan
- Program in Global Public Health, University of Illinois, Urbana-Champaign, Champaign, IL 61801
| | - Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Champaign, IL 61801
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95
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Heissler SM, Sellers JR. Four things to know about myosin light chains as reporters for non-muscle myosin-2 dynamics in live cells. Cytoskeleton (Hoboken) 2016; 72:65-70. [PMID: 25712372 DOI: 10.1002/cm.21212] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/19/2014] [Accepted: 02/03/2015] [Indexed: 11/07/2022]
Abstract
The interplay between non-muscle myosins-2 and filamentous actin results in cytoplasmic contractility which is essential for eukaryotic life. Concomitantly, there is tremendous interest in elucidating the physiological function and temporal localization of non-muscle myosin-2 in cells. A commonly used method to study the function and localization of non-muscle myosin-2 is to overexpress a fluorescent protein (FP)-tagged version of the regulatory light chain (RLC) which binds to the myosin-2 heavy chain by mass action. Caveats about this approach include findings from recent studies indicating that the RLC does not bind exclusively to the non-muscle myosin-2 heavy chain. Rather, it can also associate with the myosin heavy chains of several other classes as well as other targets than myosin. In addition, the presence of the FP moiety may compromise myosin's enzymatic and mechanical performance. This and other factors to be discussed in this commentary raise questions about the possible complications in using FP-RLC as a marker for the dynamic localization and regulatory aspects of non-muscle myosin-2 motor functions in cell biological experiments.
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Affiliation(s)
- Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
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96
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Vasquez CG, Martin AC. Force transmission in epithelial tissues. Dev Dyn 2016; 245:361-71. [PMID: 26756938 DOI: 10.1002/dvdy.24384] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/10/2015] [Accepted: 12/31/2015] [Indexed: 12/12/2022] Open
Abstract
In epithelial tissues, cells constantly generate and transmit forces between each other. Forces generated by the actomyosin cytoskeleton regulate tissue shape and structure and also provide signals that influence cells' decisions to divide, die, or differentiate. Forces are transmitted across epithelia because cells are mechanically linked through junctional complexes, and forces can propagate through the cell cytoplasm. Here, we review some of the molecular mechanisms responsible for force generation, with a specific focus on the actomyosin cortex and adherens junctions. We then discuss evidence for how these mechanisms promote cell shape changes and force transmission in tissues.
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Affiliation(s)
- Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
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97
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Modular activation of Rho1 by GPCR signalling imparts polarized myosin II activation during morphogenesis. Nat Cell Biol 2016; 18:261-70. [DOI: 10.1038/ncb3302] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/17/2015] [Indexed: 12/12/2022]
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98
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Mak M, Zaman MH, Kamm RD, Kim T. Interplay of active processes modulates tension and drives phase transition in self-renewing, motor-driven cytoskeletal networks. Nat Commun 2016; 7:10323. [PMID: 26744226 PMCID: PMC4714927 DOI: 10.1038/ncomms10323] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 11/27/2015] [Indexed: 12/23/2022] Open
Abstract
The actin cytoskeleton--a complex, nonequilibrium network consisting of filaments, actin-crosslinking proteins (ACPs) and motors--confers cell structure and functionality, from migration to morphogenesis. While the core components are recognized, much less is understood about the behaviour of the integrated, disordered and internally active system with interdependent mechano-chemical component properties. Here we use a Brownian dynamics model that incorporates key and realistic features--specifically actin turnover, ACP (un)binding and motor walking--to reveal the nature and underlying regulatory mechanisms of overarching cytoskeletal states. We generate multi-dimensional maps that show the ratio in activity of these microscopic elements determines diverse global stress profiles and the induction of nonequilibrium morphological phase transition from homogeneous to aggregated networks. In particular, actin turnover dynamics plays a prominent role in tuning stress levels and stabilizing homogeneous morphologies in crosslinked, motor-driven networks. The consequence is versatile functionality, from dynamic steady-state prestress to large, pulsed constrictions.
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Affiliation(s)
- Michael Mak
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, Massachusetts 02215, USA
| | - Muhammad H. Zaman
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, Massachusetts 02215, USA
- Howard Hughes Medical Institute, Boston University, Boston, Massachusetts 02215, USA
| | - Roger D. Kamm
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana 47907, USA
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99
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Mao Q, Lecuit T. Mechanochemical Interplay Drives Polarization in Cellular and Developmental Systems. Curr Top Dev Biol 2016; 116:633-57. [DOI: 10.1016/bs.ctdb.2015.11.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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100
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