title: The Caenorhabditis elegans vab-10 spectraplakin isoforms protect the epidermis against internal and external forces.
abstract: Morphogenesis of the Caenorhabditis elegans embryo is driven by actin microfilaments in the epidermis and by sarcomeres in body wall muscles. Both tissues are mechanically coupled, most likely through specialized attachment structures called fibrous organelles (FOs) that connect muscles to the cuticle across the epidermis. Here, we report the identification of new mutations in a gene known as vab-10, which lead to severe morphogenesis defects, and show that vab-10 corresponds to the C. elegans spectraplakin locus. Our analysis of vab-10 reveals novel insights into the role of this plakin subfamily. vab-10 generates isoforms related either to plectin (termed VAB-10A) or to microtubule actin cross-linking factor plakins (termed VAB-10B). Using specific antibodies and mutations, we show that VAB-10A and VAB-10B have distinct distributions and functions in the epidermis. Loss of VAB-10A impairs the integrity of FOs, leading to epidermal detachment from the cuticle and muscles, hence demonstrating that FOs are functionally and molecularly related to hemidesmosomes. We suggest that this isoform protects against forces external to the epidermis. In contrast, lack of VAB-10B leads to increased epidermal thickness during embryonic morphogenesis when epidermal cells change shape. We suggest that this isoform protects cells against tension that builds up within the epidermis.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, BP10142, CU de Strasbourg, Illkirch Cedex F-67404, France.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Bosher
authors.forename: Bum-Soo
authors.initials: BS
authors.lastname: Hahn
authors.forename: Renaud
authors.initials: R
authors.lastname: Legouis
authors.forename: Satis
authors.initials: S
authors.lastname: Sookhareea
authors.forename: Robby M
authors.initials: RM
authors.lastname: Weimer
authors.forename: Anne
authors.initials: A
authors.lastname: Gansmuller
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Chisholm
authors.forename: Ann M
authors.initials: AM
authors.lastname: Rose
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bessereau
authors.forename: Michel
authors.initials: M
authors.lastname: Labouesse
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000483:Alleles; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000648:ultrastructure; D004817:Epidermis / Q000196:embryology / Q000378:metabolism* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D020043:Genes, Essential; D008854:Microscopy, Electron; D009154:Mutation; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D020033:Protein Isoforms; C475260:VAB-10 protein, C elegans