title: Cingulin and actin mediate midbody-dependent apical lumen formation during polarization of epithelial cells.
abstract: Coordinated polarization of epithelial cells is a key step during morphogenesis that leads to the formation of an apical lumen. Rab11 and its interacting protein FIP5 are necessary for the targeting of apical endosomes to the midbody and apical membrane initiation site (AMIS) during lumenogenesis. However, the machinery that mediates AMIS establishment and FIP5-endosome targeting remains unknown. Here we identify a FIP5-interacting protein, Cingulin, which localizes to the AMIS and functions as a tether mediating FIP5-endosome targeting. We analysed the machinery mediating AMIS recruitment to the midbody and determined that both branched actin and microtubules are required for establishing the site of the nascent lumen. We demonstrate that the Rac1-WAVE/Scar complex mediates Cingulin recruitment to the AMIS by inducing branched actin formation, and that Cingulin directly binds to microtubule C-terminal tails through electrostatic interactions. We propose a new mechanism for apical endosome targeting and AMIS formation around the midbody during epithelial lumenogenesis.
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Mangan
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Sietsema
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Dongying
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Jeffrey K
authors.initials: JK
authors.lastname: Moore
authors.affiliation: Cell Biology Department, University of Geneva, CH-1211 GENEVA 4, Switzerland.
authors.forename: Sandra
authors.identifier: 0000-0002-6537-4818
authors.initials: S
authors.lastname: Citi
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Rytis
authors.initials: R
authors.lastname: Prekeris
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology* / Q000378:metabolism*; D061985:Madin Darby Canine Kidney Cells; D008565:Membrane Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D055672:Static Electricity; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000199:Actins; D008565:Membrane Proteins; D014404:Tubulin; D051300:Wiskott-Aldrich Syndrome Protein Family; D020830:rac1 GTP-Binding Protein