title: Remote control of insulin secretion by fat cells in Drosophila.
abstract: Insulin-like peptides (ILPs) couple growth, metabolism, longevity, and fertility with changes in nutritional availability. In Drosophila, several ILPs called Dilps are produced by the brain insulin-producing cells (IPCs), from which they are released into the hemolymph and act systemically. We show here that in response to nutrient deprivation, brain Dilps are no longer secreted and accumulate in the IPCs. We further demonstrate that the larval fat body, a functional homolog of vertebrate liver and white fat, couples the level of circulating Dilps with dietary amino acid levels by remotely controlling Dilp release through a TOR/RAPTOR-dependent mechanism. We finally use ex vivo tissue coculture to demonstrate that a humoral signal emitted by the fat body transits through the hemolymph and activates Dilp secretion in the IPCs. Thus, the availability of nutrients is remotely sensed in fat body cells and conveyed to the brain IPCs by a humoral signal controlling ILP release.
authors.affiliation: Institute for Developmental Biology and Cancer, CNRS/University of Nice-Sophia Antipolis, Parc Valrose, 06108 Nice, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Géminard
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Rulifson
authors.forename: Pierre
authors.initials: P
authors.lastname: Léopold
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; C518293:raptor protein, Drosophila