51
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Armon S, Bull MS, Aranda-Diaz A, Prakash M. Ultrafast epithelial contractions provide insights into contraction speed limits and tissue integrity. Proc Natl Acad Sci U S A 2018; 115:E10333-E10341. [PMID: 30309963 PMCID: PMC6217427 DOI: 10.1073/pnas.1802934115] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
By definition of multicellularity, all animals need to keep their cells attached and intact, despite internal and external forces. Cohesion between epithelial cells provides this key feature. To better understand fundamental limits of this cohesion, we study the epithelium mechanics of an ultrathin (∼25 μm) primitive marine animal Trichoplax adhaerens, composed essentially of two flat epithelial layers. With no known extracellular matrix and no nerves or muscles, T. adhaerens has been claimed to be the "simplest known living animal," yet is still capable of coordinated locomotion and behavior. Here we report the discovery of the fastest epithelial cellular contractions known in any metazoan, to be found in T. adhaerens dorsal epithelium (50% shrinkage of apical cell area within one second, at least an order of magnitude faster than other known examples). Live imaging reveals emergent contractile patterns that are mostly sporadic single-cell events, but also include propagating contraction waves across the tissue. We show that cell contraction speed can be explained by current models of nonmuscle actin-myosin bundles without load, while the tissue architecture and unique mechanical properties are softening the tissue, minimizing the load on a contracting cell. We propose a hypothesis, in which the physiological role of the contraction dynamics is to resist external stresses while avoiding tissue rupture ("active cohesion"), a concept that can be further applied to engineering of active materials.
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Affiliation(s)
- Shahaf Armon
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | | | | | - Manu Prakash
- Department of Bioengineering, Stanford University, Stanford, CA 94305;
- Chan Zuckerberg Biohub, San Francisco, CA 94158
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52
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Agarwal P, Zaidel-Bar R. Principles of Actomyosin Regulation In Vivo. Trends Cell Biol 2018; 29:150-163. [PMID: 30385150 DOI: 10.1016/j.tcb.2018.09.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/22/2018] [Accepted: 09/25/2018] [Indexed: 12/22/2022]
Abstract
The actomyosin cytoskeleton is responsible for most force-driven processes in cells and tissues. How it assembles into the necessary structures at the right time and place is an important question. Here, we focus on molecular mechanisms of actomyosin regulation recently elucidated in animal models, and highlight several common principles that emerge. The architecture of the actomyosin network - an important determinant of its function - results from actin polymerization, crosslinking and turnover, localized myosin activation, and contractility-driven self-organization. Spatiotemporal regulation is achieved by tissue-specific expression and subcellular localization of Rho GTPase regulators. Subcellular anchor points of actomyosin structures control the outcome of their contraction, and molecular feedback mechanisms dictate whether they are transient, cyclic, or persistent.
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Affiliation(s)
- Priti Agarwal
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Ronen Zaidel-Bar
- Mechanobiology Institute, National University of Singapore, Singapore; Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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53
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Brown JM, García-García MJ. Secretory pathway calcium ATPase 1 (SPCA1) controls mouse neural tube closure by regulating cytoskeletal dynamics. Development 2018; 145:dev.170019. [PMID: 30228103 DOI: 10.1242/dev.170019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/05/2018] [Indexed: 12/26/2022]
Abstract
Neural tube closure relies on the apical constriction of neuroepithelial cells. Research in frog and fly embryos has found links between the levels of intracellular calcium, actomyosin dynamics and apical constriction. However, genetic evidence for a role of calcium in apical constriction during mammalian neurulation is still lacking. Secretory pathway calcium ATPase (SPCA1) regulates calcium homeostasis by pumping cytosolic calcium into the Golgi apparatus. Loss of function in Spca1 causes cranial exencephaly and spinal cord defects in mice, phenotypes previously ascribed to apoptosis. However, our characterization of a novel allele of Spca1 revealed that neurulation defects in Spca1 mutants are not due to cell death, but rather to a failure of neuroepithelial cells to apically constrict. We show that SPCA1 influences cell contractility by regulating myosin II localization. Furthermore, we found that loss of Spca1 disrupts actin dynamics and the localization of the actin remodeling protein cofilin 1. Taken together, our results provide evidence that SPCA1 promotes neurulation by regulating the cytoskeletal dynamics that promote apical constriction and identify cofilin 1 as a downstream effector of SPCA1 function.
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Affiliation(s)
- Joel M Brown
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - María J García-García
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
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54
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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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55
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Blanchard GB, Étienne J, Gorfinkiel N. From pulsatile apicomedial contractility to effective epithelial mechanics. Curr Opin Genet Dev 2018; 51:78-87. [DOI: 10.1016/j.gde.2018.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/25/2018] [Accepted: 07/16/2018] [Indexed: 10/28/2022]
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56
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Urbano JM, Naylor HW, Scarpa E, Muresan L, Sanson B. Suppression of epithelial folding at actomyosin-enriched compartment boundaries downstream of Wingless signalling in Drosophila. Development 2018; 145:dev155325. [PMID: 29691225 PMCID: PMC5964650 DOI: 10.1242/dev.155325] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 03/09/2018] [Indexed: 01/01/2023]
Abstract
Epithelial folding shapes embryos and tissues during development. Here, we investigate the coupling between epithelial folding and actomyosin-enriched compartmental boundaries. The mechanistic relationship between the two is unclear, because actomyosin-enriched boundaries are not necessarily associated with folds. Also, some cases of epithelial folding occur independently of actomyosin contractility. We investigated the shallow folds called parasegment grooves that form at boundaries between anterior and posterior compartments in the early Drosophila embryo. We demonstrate that formation of these folds requires the presence of an actomyosin enrichment along the boundary cell-cell contacts. These enrichments, which require Wingless signalling, increase interfacial tension not only at the level of the adherens junctions but also along the lateral surfaces. We find that epithelial folding is normally under inhibitory control because different genetic manipulations, including depletion of the Myosin II phosphatase Flapwing, increase the depth of folds at boundaries. Fold depth correlates with the levels of Bazooka (Baz), the Par-3 homologue, along the boundary cell-cell contacts. Moreover, Wingless and Hedgehog signalling have opposite effects on fold depth at the boundary that correlate with changes in Baz planar polarity.
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Affiliation(s)
- Jose M Urbano
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Huw W Naylor
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Elena Scarpa
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Leila Muresan
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
- Cambridge Advanced Imaging Centre, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
| | - Bénédicte Sanson
- Department of Physiology, Development and Neuroscience, University of Cambridge, Anatomy Building, Downing Street, Cambridge, CB2 3DY, UK
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57
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Loison O, Weitkunat M, Kaya-Çopur A, Nascimento Alves C, Matzat T, Spletter ML, Luschnig S, Brasselet S, Lenne PF, Schnorrer F. Polarization-resolved microscopy reveals a muscle myosin motor-independent mechanism of molecular actin ordering during sarcomere maturation. PLoS Biol 2018; 16:e2004718. [PMID: 29702642 PMCID: PMC5955565 DOI: 10.1371/journal.pbio.2004718] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 05/16/2018] [Accepted: 04/09/2018] [Indexed: 11/18/2022] Open
Abstract
Sarcomeres are stereotyped force-producing mini-machines of striated muscles. Each sarcomere contains a pseudocrystalline order of bipolar actin and myosin filaments, which are linked by titin filaments. During muscle development, these three filament types need to assemble into long periodic chains of sarcomeres called myofibrils. Initially, myofibrils contain immature sarcomeres, which gradually mature into their pseudocrystalline order. Despite the general importance, our understanding of myofibril assembly and sarcomere maturation in vivo is limited, in large part because determining the molecular order of protein components during muscle development remains challenging. Here, we applied polarization-resolved microscopy to determine the molecular order of actin during myofibrillogenesis in vivo. This method revealed that, concomitantly with mechanical tension buildup in the myotube, molecular actin order increases, preceding the formation of immature sarcomeres. Mechanistically, both muscle and nonmuscle myosin contribute to this actin order gain during early stages of myofibril assembly. Actin order continues to increase while myofibrils and sarcomeres mature. Muscle myosin motor activity is required for the regular and coordinated assembly of long myofibrils but not for the high actin order buildup during sarcomere maturation. This suggests that, in muscle, other actin-binding proteins are sufficient to locally bundle or cross-link actin into highly regular arrays.
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Affiliation(s)
| | - Manuela Weitkunat
- Max Planck Institute of Biochemistry, Muscle Dynamics Group, Martinsried, Germany
| | - Aynur Kaya-Çopur
- Max Planck Institute of Biochemistry, Muscle Dynamics Group, Martinsried, Germany
| | | | - Till Matzat
- Institute of Neurobiology and Cells-in-Motion Cluster of Excellence (EXC 1003 – CiM), University of Münster, Münster, Germany
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Maria L. Spletter
- Max Planck Institute of Biochemistry, Muscle Dynamics Group, Martinsried, Germany
| | - Stefan Luschnig
- Institute of Neurobiology and Cells-in-Motion Cluster of Excellence (EXC 1003 – CiM), University of Münster, Münster, Germany
| | - Sophie Brasselet
- Aix Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
| | | | - Frank Schnorrer
- Aix Marseille Université, CNRS, IBDM, Marseille, France
- Max Planck Institute of Biochemistry, Muscle Dynamics Group, Martinsried, Germany
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58
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Architecture shapes contractility in actomyosin networks. Curr Opin Cell Biol 2018; 50:79-85. [PMID: 29482169 DOI: 10.1016/j.ceb.2018.01.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 01/30/2018] [Indexed: 01/03/2023]
Abstract
Myosin-driven contraction of the actin cytoskeleton is at the base of cell and tissue morphogenesis. At the molecular level, myosin motors drive contraction by sliding actin filaments past one another using energy produced by ATP hydrolysis. How this microscopic sliding activity gives rise to cell-scale contractions has been an active research question first in muscle cells, and over the last few decades in non-muscle cells. While many early investigations focused on myosin motor activity, increasingly, the nanoscale architecture of the actin network emerges as a key regulator of contractility. Here we review theoretical and in vitro reconstitution studies that have uncovered some of the key mechanisms by which actin network organization controls contractile tension generation. We then discuss recent findings indicating that similar principles apply in cells.
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59
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Abstract
D'Arcy Thompson was a proponent of applying mathematical and physical principles to biological systems, an approach that is becoming increasingly common in developmental biology. Indeed, the recent integration of quantitative experimental data, force measurements and mathematical modeling has changed our understanding of morphogenesis - the shaping of an organism during development. Emerging evidence suggests that the subcellular organization of contractile cytoskeletal networks plays a key role in force generation, while on the tissue level the spatial organization of forces determines the morphogenetic output. Inspired by D'Arcy Thompson's On Growth and Form, we review our current understanding of how biological forms are created and maintained by the generation and organization of contractile forces at the cell and tissue levels. We focus on recent advances in our understanding of how cells actively sculpt tissues and how forces are involved in specific morphogenetic processes.
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Affiliation(s)
- Natalie C Heer
- 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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60
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Perez-Mockus G, Mazouni K, Roca V, Corradi G, Conte V, Schweisguth F. Spatial regulation of contractility by Neuralized and Bearded during furrow invagination in Drosophila. Nat Commun 2017; 8:1594. [PMID: 29150614 PMCID: PMC5693868 DOI: 10.1038/s41467-017-01482-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 09/21/2017] [Indexed: 12/22/2022] Open
Abstract
Embryo-scale morphogenesis arises from patterned mechanical forces. During Drosophila gastrulation, actomyosin contractility drives apical constriction in ventral cells, leading to furrow formation and mesoderm invagination. It remains unclear whether and how mechanical properties of the ectoderm influence this process. Here, we show that Neuralized (Neur), an E3 ubiquitin ligase active in the mesoderm, regulates collective apical constriction and furrow formation. Conversely, the Bearded (Brd) proteins antagonize maternal Neur and lower medial-apical contractility in the ectoderm: in Brd-mutant embryos, the ventral furrow invaginates properly but rapidly unfolds as medial MyoII levels increase in the ectoderm. Increasing contractility in the ectoderm via activated Rho similarly triggers furrow unfolding whereas decreasing contractility restores furrow invagination in Brd-mutant embryos. Thus, the inhibition of Neur by Brd in the ectoderm differentiates the mechanics of the ectoderm from that of the mesoderm and patterns the activity of MyoII along the dorsal-ventral axis.
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Affiliation(s)
- Gantas Perez-Mockus
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015, Paris, France.,CNRS, UMR3738, F-75015, Paris, France.,Univ. Pierre et Marie Curie, Cellule Pasteur UPMC, F-75015, Paris, France
| | - Khalil Mazouni
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015, Paris, France.,CNRS, UMR3738, F-75015, Paris, France
| | - Vanessa Roca
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015, Paris, France.,CNRS, UMR3738, F-75015, Paris, France
| | - Giulia Corradi
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015, Paris, France.,CNRS, UMR3738, F-75015, Paris, France
| | - Vito Conte
- Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology, 08028, Barcelona, Spain.
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015, Paris, France. .,CNRS, UMR3738, F-75015, Paris, France.
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61
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Viscoelastic Dissipation Stabilizes Cell Shape Changes during Tissue Morphogenesis. Curr Biol 2017; 27:3132-3142.e4. [DOI: 10.1016/j.cub.2017.09.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/27/2017] [Accepted: 09/05/2017] [Indexed: 12/22/2022]
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62
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Abstract
Contractile actomyosin networks are central to cell shape change, rearrangements, and migration during animal tissue morphogenesis. In this issue of Developmental Cell, Coravos and Martin (2016) report that the actin network is radially polarized in apically constricting cells, suggesting a constriction model similar to the contraction mechanism in muscle sarcomeres.
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63
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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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64
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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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65
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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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66
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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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67
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Milanini J, Fayad R, Partisani M, Lecine P, Borg JP, Franco M, Luton F. EFA6 regulates lumen formation through alpha-actinin 1. J Cell Sci 2017; 131:jcs.209361. [DOI: 10.1242/jcs.209361] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 12/11/2017] [Indexed: 01/07/2023] Open
Abstract
A key step of epithelial morphogenesis is the creation of the lumen. Luminogenesis by hollowing proceeds through the fusion of apical vesicles at cell-cell contact. The small nascent lumens grow through extension, coalescence and enlargement coordinated with cell division to give rise to a single central lumen. Here, using MDCK cells grown in 3D-culture, we show that EFA6A participates in luminogenesis. EFA6A recruits α-actinin 1 (ACTN1) through direct binding. In polarized cells, ACTN1 was found to be enriched at the tight junction where it acts as a primary effector of EFA6A for normal luminogenesis. Both proteins are essential for the lumen extension and enlargement, where they mediate their effect by regulating the cortical acto-myosin contractility. Finally, ACTN1 was also found to act as an effector for the isoform EFA6B in the human mammary tumoral MCF7 cell line. EFA6B restored the glandular morphology of this tumoral cell line in an ACTN1-dependent manner. Thus, we identified new regulators of cyst luminogenesis essential for the proper maturation of a newly-formed lumen into a single central lumen.
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Affiliation(s)
- Julie Milanini
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Racha Fayad
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Mariagrazia Partisani
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Patrick Lecine
- Centre de Recherche en Cancérologie de Marseille (CRCM), "Cell Polarity, Cell Signalling and Cancer", Equipe Labellisée Ligue Contre le Cancer, Inserm U1068, Marseille, F-13009, France; CNRS, UMR7258, Marseille, F-13009, France; Institut Paoli-Calmettes, Marseille, F-13009, France; Aix-Marseille University, UM105, Marseille, F-13284, France
- present address: BIOASTER, Lyon, France
| | - Jean-Paul Borg
- Centre de Recherche en Cancérologie de Marseille (CRCM), "Cell Polarity, Cell Signalling and Cancer", Equipe Labellisée Ligue Contre le Cancer, Inserm U1068, Marseille, F-13009, France; CNRS, UMR7258, Marseille, F-13009, France; Institut Paoli-Calmettes, Marseille, F-13009, France; Aix-Marseille University, UM105, Marseille, F-13284, France
| | - Michel Franco
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
| | - Frédéric Luton
- Université Côte d'Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Valbonne, France
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