title: Nanotubes mediate niche-stem-cell signalling in the Drosophila testis.
abstract: Stem cell niches provide resident stem cells with signals that specify their identity. Niche signals act over a short range such that only stem cells but not their differentiating progeny receive the self-renewing signals. However, the cellular mechanisms that limit niche signalling to stem cells remain poorly understood. Here we show that the Drosophila male germline stem cells form previously unrecognized structures, microtubule-based nanotubes, which extend into the hub, a major niche component. Microtubule-based nanotubes are observed specifically within germline stem cell populations, and require intraflagellar transport proteins for their formation. The bone morphogenetic protein (BMP) receptor Tkv localizes to microtubule-based nanotubes. Perturbation of microtubule-based nanotubes compromises activation of Dpp signalling within germline stem cells, leading to germline stem cell loss. Moreover, Dpp ligand and Tkv receptor interaction is necessary and sufficient for microtubule-based nanotube formation. We propose that microtubule-based nanotubes provide a novel mechanism for selective receptor-ligand interaction, contributing to the short-range nature of niche-stem-cell signalling.
authors.affiliation: 1] Life Sciences Institute, Department of Cell and Developmental Biology Medical School, University of Michigan, Ann Arbor, Michigan 48109, USA [2] Howard Hughes Medical Institute, University of Michigan Ann Arbor, Michigan 48109, USA [3] Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
authors.forename: Mayu
authors.initials: M
authors.lastname: Inaba
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Buszczak
authors.affiliation: 1] Life Sciences Institute, Department of Cell and Developmental Biology Medical School, University of Michigan, Ann Arbor, Michigan 48109, USA [2] Howard Hughes Medical Institute, University of Michigan Ann Arbor, Michigan 48109, USA.
authors.forename: Yukiko M
authors.initials: YM
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D008297:Male; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism*; D043942:Nanotubes; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D055153:Stem Cell Niche / Q000502:physiology*; D013737:Testis / Q000166:cytology*
chemical_list: D029721:Drosophila Proteins; D008024:Ligands; D011956:Receptors, Cell Surface; C064196:dpp protein, Drosophila; C090169:tkv protein, Drosophila; D017346:Protein Serine-Threonine Kinases