RhoA GTPase inhibition organizes contraction during epithelial 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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The Drosophila afadin homologue Canoe regulates linkage of the actin cytoskeleton to adherens junctions during apical constriction

The Journal of Cell Biology ◽

10.1083/jcb.200904001 ◽

2009 ◽

Vol 186 (1) ◽

pp. 57-73 ◽

Cited By ~ 150

Author(s):

Jessica K. Sawyer ◽

Nathan J. Harris ◽

Kevin C. Slep ◽

Ulrike Gaul ◽

Mark Peifer

Keyword(s):

Actin Cytoskeleton ◽

Cell Shape ◽

Shape Change ◽

Adherens Junctions ◽

Apical Constriction ◽

Cell Shape Change ◽

Mediate Cell Adhesion ◽

Mediate Cell ◽

Actomyosin Cytoskeleton ◽

Core Part

Cadherin-based adherens junctions (AJs) mediate cell adhesion and regulate cell shape change. The nectin–afadin complex also localizes to AJs and links to the cytoskeleton. Mammalian afadin has been suggested to be essential for adhesion and polarity establishment, but its mechanism of action is unclear. In contrast, Drosophila melanogaster’s afadin homologue Canoe (Cno) has suggested roles in signal transduction during morphogenesis. We completely removed Cno from embryos, testing these hypotheses. Surprisingly, Cno is not essential for AJ assembly or for AJ maintenance in many tissues. However, morphogenesis is impaired from the start. Apical constriction of mesodermal cells initiates but is not completed. The actomyosin cytoskeleton disconnects from AJs, uncoupling actomyosin constriction and cell shape change. Cno has multiple direct interactions with AJ proteins, but is not a core part of the cadherin–catenin complex. Instead, Cno localizes to AJs by a Rap1- and actin-dependent mechanism. These data suggest that Cno regulates linkage between AJs and the actin cytoskeleton during morphogenesis.

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Dynamic myosin phosphorylation regulates contractile pulses and tissue integrity during epithelial morphogenesis

The Journal of Cell Biology ◽

10.1083/jcb.201402004 ◽

2014 ◽

Vol 206 (3) ◽

pp. 435-450 ◽

Cited By ~ 101

Author(s):

Claudia G. Vasquez ◽

Mike Tworoger ◽

Adam C. Martin

Keyword(s):

Cell Shape ◽

Shape Change ◽

Epithelial Morphogenesis ◽

Nonmuscle Myosin ◽

Apical Constriction ◽

Tissue Integrity ◽

Cell Shape Change ◽

Nonmuscle Myosin Ii ◽

A Cell ◽

Coupling Dynamic

Apical constriction is a cell shape change that promotes epithelial bending. Activation of nonmuscle myosin II (Myo-II) by kinases such as Rho-associated kinase (Rok) is important to generate contractile force during apical constriction. Cycles of Myo-II assembly and disassembly, or pulses, are associated with apical constriction during Drosophila melanogaster gastrulation. It is not understood whether Myo-II phosphoregulation organizes contractile pulses or whether pulses are important for tissue morphogenesis. Here, we show that Myo-II pulses are associated with pulses of apical Rok. Mutants that mimic Myo-II light chain phosphorylation or depletion of myosin phosphatase inhibit Myo-II contractile pulses, disrupting both actomyosin coalescence into apical foci and cycles of Myo-II assembly/disassembly. Thus, coupling dynamic Myo-II phosphorylation to upstream signals organizes contractile Myo-II pulses in both space and time. Mutants that mimic Myo-II phosphorylation undergo continuous, rather than incremental, apical constriction. These mutants fail to maintain intercellular actomyosin network connections during tissue invagination, suggesting that Myo-II pulses are required for tissue integrity during morphogenesis.

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A Critical Role of the PINCH-Integrin-linked Kinase Interaction in the Regulation of Cell Shape Change and Migration

Journal of Biological Chemistry ◽

10.1074/jbc.m108257200 ◽

2001 ◽

Vol 277 (1) ◽

pp. 318-326 ◽

Cited By ~ 82

Author(s):

Yongjun Zhang ◽

Lida Guo ◽

Ka Chen ◽

Chuanyue Wu

Keyword(s):

Cell Shape ◽

Shape Change ◽

Critical Role ◽

Cell Shape Change ◽

Integrin Linked Kinase ◽

And Migration

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Apical constriction: A cell shape change that can drive morphogenesis

Developmental Biology ◽

10.1016/j.ydbio.2009.09.009 ◽

2010 ◽

Vol 341 (1) ◽

pp. 5-19 ◽

Cited By ~ 267

Author(s):

Jacob M. Sawyer ◽

Jessica R. Harrell ◽

Gidi Shemer ◽

Jessica Sullivan-Brown ◽

Minna Roh-Johnson ◽

...

Keyword(s):

Cell Shape ◽

Shape Change ◽

Apical Constriction ◽

Cell Shape Change ◽

A Cell

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Uncoupling apical constriction from tissue invagination

eLife ◽

10.7554/elife.22235 ◽

2017 ◽

Vol 6 ◽

Cited By ~ 29

Author(s):

SeYeon Chung ◽

Sangjoon Kim ◽

Deborah J Andrew

Keyword(s):

Cell Shape ◽

Shape Change ◽

Rho Kinase ◽

Tissue Level ◽

Tube Formation ◽

Intrinsic Properties ◽

Apical Constriction ◽

Cell Shape Change ◽

Polarized Epithelia ◽

Muscle Myosin

Apical constriction is a widely utilized cell shape change linked to folding, bending and invagination of polarized epithelia. It remains unclear how apical constriction is regulated spatiotemporally during tissue invagination and how this cellular process contributes to tube formation in different developmental contexts. Using Drosophila salivary gland (SG) invagination as a model, we show that regulation of folded gastrulation expression by the Fork head transcription factor is required for apicomedial accumulation of Rho kinase and non-muscle myosin II, which coordinate apical constriction. We demonstrate that neither loss of spatially coordinated apical constriction nor its complete blockage prevent internalization and tube formation, although such manipulations affect the geometry of invagination. When apical constriction is disrupted, compressing force generated by a tissue-level myosin cable contributes to SG invagination. We demonstrate that fully elongated polarized SGs can form outside the embryo, suggesting that tube formation and elongation are intrinsic properties of the SG.

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Faculty Opinions recommendation of folded gastrulation, cell shape change and the control of myosin localization.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1027741.793481719 ◽

2013 ◽

Author(s):

Alpha Yap

Keyword(s):

Cell Shape ◽

Shape Change ◽

Cell Shape Change

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Morphological change of cell-membrane-integrated crystalline structure induced by cell shape change inEuglena gracilis

PROTOPLASMA ◽

10.1007/bf02524264 ◽

2000 ◽

Vol 214 (1-2) ◽

pp. 73-79 ◽

Cited By ~ 3

Author(s):

K. Murata ◽

M. Okamoto ◽

T. Suzaki

Keyword(s):

Cell Membrane ◽

Morphological Change ◽

Crystalline Structure ◽

Cell Shape ◽

Shape Change ◽

Cell Shape Change

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The role of microtubules in chick blastoderm expansion—a quantitative study using colchicine

Development ◽

10.1242/dev.34.1.265 ◽

1975 ◽

Vol 34 (1) ◽

pp. 265-277

Author(s):

J. R. Downie

Keyword(s):

Cell Division ◽

Cell Shape ◽

Shape Change ◽

Cell Sheet ◽

Cell Movement ◽

Vitelline Membrane ◽

General Context ◽

Chick Blastoderm ◽

Cell Shape Change ◽

Cytoplasmic Microtubules

Since their discovery, cytoplasmic microtubules have been much studied in the context of cell movement and cell shape change. Much of the work has used drugs, particularly colchicine and its relatives, which break down microtubules — the so-called anti-tubulins. Colchicine inhibits the orientated movements of many cell types in vitro, and disrupts cell shape change in several morphogenetic situations. The investigation reported here used chick blastoderm expansion in New culture in an attempt to quantify the colchicine effect on orientated cell movement. However, although colchicine could halt blastoderm expansion entirely, a simple interpretation was not possible. (1) Colchicine at concentrations capable of blocking mitosis, and of disrupting all or most of the cytoplasmic microtubules of the cells studied, inhibited blastoderm expansion, often resulting in an overall retraction of the cell sheet. (2) Though blastoderm expansion does normally involve considerable cell proliferation, the colchicine effect could not be ascribed to a block on cell division since aminopterin, which stops cell division without affecting microtubules, did not inhibit expansion. (3) Blastoderm expansion is effected by the locomotion of a specialized band of edge cells at the blastoderm periphery. These are the only cells normally attached to the vitelline membrane — the substrate for expansion. When most of the blastoderm was excised, leaving the band of edge cells, and the cultures then treated with colchicine, expansion occurred normally. The colchicine effect on blastoderm expansion could not therefore be ascribed to a direct effect on the edge cells. (4) An alternative site of action of the drug is the remaining cells of the blastoderm. These normally become progressively flatter as expansion proceeds. If flattening in these cells is even partially dependent on their cytoplasmic microtubules, disruption of these microtubules might result in the inherent contractility of the cells resisting and eventually halting edge cell migration. That cell shape in these cells is dependent on microtubules was demonstrated by treating flat blastoderm fragments with colchicine. On incubation, the area occupied by these fragments decreased by 25–30 % more than controls. The significance of these results in the general context of orientated cell movements and cell shape determination is discussed, with particular emphasis on the analogous system of Fundulus epiboly.

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Autonomy and non-autonomy in Drosophila mesoderm determination and morphogenesis

Development ◽

10.1242/dev.120.4.853 ◽

1994 ◽

Vol 120 (4) ◽

pp. 853-859 ◽

Cited By ~ 3

Author(s):

M. Leptin ◽

S. Roth

Keyword(s):

Cell Shape ◽

Shape Change ◽

Developmental Program ◽

Cell Shape Change ◽

Ventral Furrow ◽

Large Numbers ◽

The Individual ◽

Mutant Cells ◽

Transplantation Experiments ◽

Shape Changes

The mesoderm in Drosophila invaginates by a series of characteristic cell shape changes. Mosaics of wild-type cells in an environment of mutant cells incapable of making mesodermal invaginations show that this morphogenetic behaviour does not require interactions between large numbers of cells but that small patches of cells can invaginate independent of their neighbours' behaviour. While the initiation of cell shape change is locally autonomous, the shapes the cells assume are partly determined by the individual cell's environment. Cytoplasmic transplantation experiments show that areas of cells expressing mesodermal genes ectopically at any position in the egg form an invagination. We propose that ventral furrow formation is the consequence of all prospective mesodermal cells independently following their developmental program. Gene expression at the border of the mesoderm is induced by the apposition of mesodermal and non-mesodermal cells.

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