title: LC-MS proteomics analysis of the insulin/IGF-1-deficient Caenorhabditis elegans daf-2(e1370) mutant reveals extensive restructuring of intermediary metabolism.
abstract: The insulin/IGF-1 receptor is a major known determinant of dauer formation, stress resistance, longevity, and metabolism in Caenorhabditis elegans. In the past, whole-genome transcript profiling was used extensively to study differential gene expression in response to reduced insulin/IGF-1 signaling, including the expression levels of metabolism-associated genes. Taking advantage of the recent developments in quantitative liquid chromatography mass spectrometry (LC-MS)-based proteomics, we profiled the proteomic changes that occur in response to activation of the DAF-16 transcription factor in the germline-less glp-4(bn2);daf-2(e1370) receptor mutant. Strikingly, the daf-2 profile suggests extensive reorganization of intermediary metabolism, characterized by the upregulation of many core intermediary metabolic pathways. These include glycolysis/gluconeogenesis, glycogenesis, pentose phosphate cycle, citric acid cycle, glyoxylate shunt, fatty acid β-oxidation, one-carbon metabolism, propionate and tyrosine catabolism, and complexes I, II, III, and V of the electron transport chain. Interestingly, we found simultaneous activation of reciprocally regulated metabolic pathways, which is indicative of spatiotemporal coordination of energy metabolism and/or extensive post-translational regulation of these enzymes. This restructuring of daf-2 metabolism is reminiscent to that of hypometabolic dauers, allowing the efficient and economical utilization of internal nutrient reserves and possibly also shunting metabolites through alternative energy-generating pathways to sustain longevity.
authors.affiliation: Biology Department, Ghent University , Proeftuinstraat 86 N1, B-9000 Ghent, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Depuydt
authors.forename: Fang
authors.initials: F
authors.lastname: Xie
authors.forename: Vladislav A
authors.initials: VA
authors.lastname: Petyuk
authors.forename: Arne
authors.initials: A
authors.lastname: Smolders
authors.forename: Heather M
authors.initials: HM
authors.lastname: Brewer
authors.forename: David G
authors.initials: DG
authors.lastname: Camp
authors.forename: Richard D
authors.initials: RD
authors.lastname: Smith
authors.forename: Bart P
authors.initials: BP
authors.lastname: Braeckman
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051858:Forkhead Transcription Factors; D055785:Gene Knockdown Techniques; D007328:Insulin / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009154:Mutation / Q000235:genetics; D020543:Proteome / Q000032:analysis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D011972:Receptor, Insulin / Q000235:genetics*; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D051858:Forkhead Transcription Factors; D007328:Insulin; D020543:Proteome; D014157:Transcription Factors; C108831:daf-16 protein, C elegans; D007334:Insulin-Like Growth Factor I; C107483:DAF-2 protein, C elegans; D011972:Receptor, Insulin