title: Vesicle-Mediated Steroid Hormone Secretion in Drosophila melanogaster.
abstract: Steroid hormones are a large family of cholesterol derivatives regulating development and physiology in both the animal and plant kingdoms, but little is known concerning mechanisms of their secretion from steroidogenic tissues. Here, we present evidence that in Drosophila, endocrine release of the steroid hormone ecdysone is mediated through a regulated vesicular trafficking mechanism. Inhibition of calcium signaling in the steroidogenic prothoracic gland results in the accumulation of unreleased ecdysone, and the knockdown of calcium-mediated vesicle exocytosis components in the gland caused developmental defects due to deficiency of ecdysone. Accumulation of synaptotagmin-labeled vesicles in the gland is observed when calcium signaling is disrupted, and these vesicles contain an ABC transporter that functions as an ecdysone pump to fill vesicles. We propose that trafficking of steroid hormones out of endocrine cells is not always through a simple diffusion mechanism as presently thought, but instead can involve a regulated vesicle-mediated release process.
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA; Department of Entomology, Institute for Integrative Genome Biology, Center for Disease Vector Research, University of California, Riverside, Riverside, CA 92521, USA. Electronic address: naoki.yamanaka@ucr.edu.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamanaka
authors.affiliation: University Imaging Centers, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Marqués
authors.affiliation: Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: moconnor@umn.edu.
authors.forename: Michael B
authors.initials: MB
authors.lastname: O'Connor
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004058:Diffusion; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D004440:Ecdysone / Q000378:metabolism*; D004702:Endocrine Glands / Q000378:metabolism; D005089:Exocytosis; D055785:Gene Knockdown Techniques; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000166:cytology / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism*; D050857:Synaptotagmins / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; C102514:Atet protein, Drosophila; D029721:Drosophila Proteins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D050857:Synaptotagmins; D004440:Ecdysone; D000255:Adenosine Triphosphate