title: Stable and dynamic microtubules coordinately determine and maintain Drosophila bristle shape.
abstract: Within interphase cells, microtubules (MTs) are organized in a cell-specific manner to support cell shape and function. Here, we report that coordination between stable and dynamic MTs determines and maintains the highly elongated bristle cell shape. By following MT-decorating hooks and by tracking EB1 we identified two MT populations within bristles: a stable MT population polarized with their minus ends distal to the cell body, and a dynamic MT population that exhibits mixed polarity. Manipulating MT dynamics by Klp10A downregulation demonstrates that MTs can initiate new shaft extensions and thus possess the ability to determine growth direction. Actin filament bundling subsequently supports the newly formed shaft extensions. Analysis of ik2 mutant bristles, established by elongation defects in the Drosophila ikkε homolog, led to the observation that stable and dynamic MT orientation and polarized organization are important for proper bristle elongation. Thus, we demonstrate for the first time that coordination between stable and dynamic MT sets that are axially organized yet differently polarized drives cell elongation.
authors.affiliation: Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel.
authors.forename: Amir
authors.initials: A
authors.lastname: Bitan
authors.forename: Ido
authors.initials: I
authors.lastname: Rosenbaum
authors.forename: Uri
authors.initials: U
authors.lastname: Abdu
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016764:Cell Polarity / Q000502:physiology; D048430:Cell Shape / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051550:I-kappa B Kinase / Q000378:metabolism; D007399:Interphase / Q000502:physiology*; D016547:Kinesins / Q000378:metabolism; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000502:physiology* / Q000648:ultrastructure; D010590:Phalloidine; D058618:Sensilla / Q000166:cytology* / Q000502:physiology; D059008:Time-Lapse Imaging
chemical_list: D029721:Drosophila Proteins; C405804:EB1 microtubule binding proteins; D008869:Microtubule-Associated Proteins; D049452:Green Fluorescent Proteins; D010590:Phalloidine; D051550:I-kappa B Kinase; C481339:KLP10A protein, Drosophila; D016547:Kinesins