title: Microtubule-dependent balanced cell contraction and luminal-matrix modification accelerate epithelial tube fusion.
abstract: Connection of tubules into larger networks is the key process for the development of circulatory systems. In Drosophila development, tip cells of the tracheal system lead the migration of each branch and connect tubules by adhering to each other and simultaneously changing into a torus-shape. We show that as adhesion sites form between fusion cells, myosin and microtubules form polarized bundles that connect the new adhesion site to the cells' microtubule-organizing centres, and that E-cadherin and retrograde recycling endosomes are preferentially deposited at the new adhesion site. We demonstrate that microtubules help balancing tip cell contraction, which is driven by myosin, and is required for adhesion and tube fusion. We also show that retrograde recycling and directed secretion of a specific matrix protein into the fusion-cell interface promote fusion. We propose that microtubule bundles connecting these cell-cell interfaces coordinate cell contractility and apical secretion to facilitate tube fusion.
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
authors.forename: Kagayaki
authors.initials: K
authors.lastname: Kato
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
authors.forename: Bo
authors.initials: B
authors.lastname: Dong
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
authors.forename: Housei
authors.initials: H
authors.lastname: Wada
authors.affiliation: Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, Illinois 60611, USA.
authors.forename: Miho
authors.initials: M
authors.lastname: Tanaka-Matakatsu
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Yagi
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 Rokko-dai, Nada-ku, Kobe, Hyogo 657-8501, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D015820:Cadherins / Q000378:metabolism; D002459:Cell Fusion; D002465:Cell Movement; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology*; D005109:Extracellular Matrix / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007365:Intercellular Junctions / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009218:Myosins / Q000378:metabolism; D010641:Phenotype; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014132:Trachea / Q000166:cytology
chemical_list: D000199:Actins; D015820:Cadherins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D009218:Myosins