PT  - JOURNAL ARTICLE
AU  - Lynch, Allison M.
AU  - Lucas, Bethany G.
AU  - Winkelman, Jonathan D.
AU  - Martin, Sterling C.T.
AU  - Block, Samuel D.
AU  - Audhya, Anjon
AU  - Gardel, Margaret L.
AU  - Hardin, Jeff
TI  - TES-1/Tes protects junctional actin networks under tension from self-injury during epidermal morphogenesis in the <em>C. elegans</em> embryo
AID  - 10.1101/2021.09.30.462556
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.09.30.462556
4099  - http://biorxiv.org/content/early/2021/10/01/2021.09.30.462556.short
4100  - http://biorxiv.org/content/early/2021/10/01/2021.09.30.462556.full
AB  - During embryonic morphogenesis, the integrity of epithelial tissues depends on the ability of cells in tissue sheets to undergo rapid changes in cell shape while preventing self-injury to junctional actin networks. LIM domain-containing repeat (LCR) proteins are recruited to sites of strained actin filaments in cultured cells [1–3], and are therefore promising candidates for mediating self-healing of actin networks, but whether they play similar roles in living organisms has not been determined. Here, we establish roles for Caenorhabditis elegans TES-1/Tes, an actin-binding LCR protein present at apical junctions, during epithelial morphogenesis. TES-1::GFP is recruited to apical junctions during embryonic elongation, when junctions are under tension; in embryos in which stochastic failure of cell elongation occurs, TES-1 is only strongly recruited to junctions in cells that successfully elongate, and recruitment is severely compromised in genetic backgrounds in which cell shape changes do not successfully occur. tes-1 mutant embryos display junctional F-actin defects, and loss of TES-1 strongly enhances tension-dependent injury of junctional actin networks in hypomorphic mutant backgrounds for CCC components, suggesting that TES-1 helps to prevent self-injury of junctional actin networks during rapid cell shape change. Consistent with such role, a fragment of TES-1 containing its LIM domains localizes to stress fiber strain sites (SFSS) in cultured vertebrate cells. Together, these data establish TES-1 as a tension-sensitive stabilizer of the junctional actin cytoskeleton during embryonic morphogenesis.Competing Interest StatementThe authors have declared no competing interest.AJadherens junctionCCCcadherin-catenin complexCFBcircumferential filament bundleDICdifferential interference contrastLIMLin-l1, Isl-1, Mec-3PETPrickle, Espinas, Testin