title: Regulators of autophagosome formation in Drosophila muscles.
abstract: Given the diversity of autophagy targets and regulation, it is important to characterize autophagy in various cell types and conditions. We used a primary myocyte cell culture system to assay the role of putative autophagy regulators in the specific context of skeletal muscle. By treating the cultures with rapamycin (Rap) and chloroquine (CQ) we induced an autophagic response, fully suppressible by knockdown of core ATG genes. We screened D. melanogaster orthologs of a previously reported mammalian autophagy protein-protein interaction network, identifying several proteins required for autophagosome formation in muscle cells, including orthologs of the Rab regulators RabGap1 and Rab3Gap1. The screen also highlighted the critical roles of the proteasome and glycogen metabolism in regulating autophagy. Specifically, sustained proteasome inhibition inhibited autophagosome formation both in primary culture and larval skeletal muscle, even though autophagy normally acts to suppress ubiquitin aggregate formation in these tissues. In addition, analyses of glycogen metabolic genes in both primary cultured and larval muscles indicated that glycogen storage enhances the autophagic response to starvation, an important insight given the link between glycogen storage disorders, autophagy, and muscle function.
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Zirin
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Joppe
authors.initials: J
authors.lastname: Nieuwenhuis
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Samsonova
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Rong
authors.initials: R
authors.lastname: Tao
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America; Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Norbert
authors.initials: N
authors.lastname: Perrimon
mesh_terms: D000818:Animals; D001343:Autophagy / Q000235:genetics*; D002450:Cell Communication / Q000235:genetics; D002738:Chloroquine / Q000008:administration & dosage; D004331:Drosophila melanogaster; D020690:GTPase-Activating Proteins / Q000235:genetics / Q000378:metabolism; D006003:Glycogen / Q000096:biosynthesis; D007814:Larva; D032342:Muscle Cells / Q000166:cytology / Q000378:metabolism; D018482:Muscle, Skeletal / Q000254:growth & development* / Q000378:metabolism; D009135:Muscular Diseases / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D010588:Phagosomes / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D060066:Protein Interaction Maps / Q000235:genetics*; D020123:Sirolimus / Q000008:administration & dosage; D025801:Ubiquitin / Q000235:genetics; D020692:rab3 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020690:GTPase-Activating Proteins; D025801:Ubiquitin; D002738:Chloroquine; D006003:Glycogen; D020692:rab3 GTP-Binding Proteins; D020123:Sirolimus