title: Balance between apical membrane growth and luminal matrix resistance determines epithelial tubule shape.
abstract: The morphological stability of biological tubes is crucial for the efficient circulation of fluids and gases. Failure of this stability causes irregularly shaped tubes found in multiple pathological conditions. Here, we report that Drosophila mutants of the ESCRT III component Shrub/Vps32 exhibit a strikingly elongated sinusoidal tube phenotype. This is caused by excessive apical membrane synthesis accompanied by the ectopic accumulation and overactivation of Crumbs in swollen endosomes. Furthermore, we demonstrate that the apical extracellular matrix (aECM) of the tracheal tube is a viscoelastic material coupled with the apical membrane. We present a simple mechanical model in which aECM elasticity, apical membrane growth, and their interaction are three vital parameters determining the stability of biological tubes. Our findings demonstrate a mechanical role for the extracellular matrix and suggest that the interaction of the apical membrane and an elastic aECM determines the final morphology of biological tubes independent of cell shape.
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan. Electronic address: dong@cdb.riken.jp.
authors.forename: Bo
authors.initials: B
authors.lastname: Dong
authors.affiliation: Physicochimie Curie (Institut Curie/CNRS-UMR168/UPMC), Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
authors.forename: Edouard
authors.initials: E
authors.lastname: Hannezo
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan. Electronic address: shayashi@cdb.riken.jp.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D048430:Cell Shape / Q000502:physiology; D004330:Drosophila / Q000254:growth & development*; D029721:Drosophila Proteins / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000502:physiology*; D004848:Epithelium / Q000254:growth & development*; D005109:Extracellular Matrix / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology*; D014132:Trachea / Q000166:cytology / Q000254:growth & development*
chemical_list: D029721:Drosophila Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D009419:Nerve Tissue Proteins; C513148:Shrb protein, Drosophila