title: Lasp anchors the Drosophila male stem cell niche and mediates spermatid individualization.
abstract: Lasp family proteins contain an amino-terminal LIM domain, two actin-binding nebulin repeats and a carboxyl-terminal SH3 domain. Vertebrate Lasp-1 localizes to focal adhesions and the leading edge of migrating cells, and is required for cell migration. To assess the in vivo function of Lasp, we generated a null mutant in Drosophila Lasp. Lasp(1) is homozygous viable, but male sterile. In Lasp mutants the stem cell niche is no longer anchored to the apical tip of the testis, and actin cone migration is perturbed resulting in improper spermatid individualization. Hub cell mislocalization can by phenocopied by expressing Lasp or betaPS integrin RNAi transgenes in somatic cells, and Lasp genetically interacts with betaPS integrin, demonstrating that Lasp functions together with integrins in hub cells to anchor the stem cell niche. Finally, we show that the stem cell niche is maintained even if it is not properly localized.
authors.affiliation: Department of Biology, McGill University, 1205 Dr. Penfield Avenue, Montreal, QC, Canada H3A 1B1.
authors.forename: Soojin
authors.initials: S
authors.lastname: Lee
authors.forename: Lili
authors.initials: L
authors.lastname: Zhou
authors.forename: Jieun
authors.initials: J
authors.lastname: Kim
authors.forename: Stephen
authors.initials: S
authors.lastname: Kalbfleisch
authors.forename: Frieder
authors.initials: F
authors.lastname: Schöck
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics; D005260:Female; D017344:Genes, Insect; D007246:Infertility; D008297:Male; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010053:Ovary / Q000166:cytology; D013087:Spermatids / Q000166:cytology* / Q000648:ultrastructure; D055153:Stem Cell Niche / Q000166:cytology* / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology*; D013737:Testis / Q000166:cytology / Q000648:ultrastructure
chemical_list: D000199:Actins; D029721:Drosophila Proteins; C533497:Lasp protein, Drosophila; D008840:Microfilament Proteins