title: Rheb GTPase is a direct target of TSC2 GAP activity and regulates mTOR signaling.
abstract: Tuberous sclerosis complex (TSC) is a genetic disease caused by mutation in either TSC1 or TSC2. The TSC1 and TSC2 gene products form a functional complex and inhibit phosphorylation of S6K and 4EBP1. These functions of TSC1/TSC2 are likely mediated by mTOR. Here we report that TSC2 is a GTPase-activating protein (GAP) toward Rheb, a Ras family GTPase. Rheb stimulates phosphorylation of S6K and 4EBP1. This function of Rheb is blocked by rapamycin and dominant-negative mTOR. Rheb stimulates the phosphorylation of mTOR and plays an essential role in regulation of S6K and 4EBP1 in response to nutrients and cellular energy status. Our data demonstrate that Rheb acts downstream of TSC1/TSC2 and upstream of mTOR to regulate cell growth.
authors.affiliation: Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Inoki
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Tian
authors.initials: T
authors.lastname: Xu
authors.forename: Kun-Liang
authors.initials: KL
authors.lastname: Guan
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D002455:Cell Division; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D020558:GTP Phosphohydrolases / Q000378:metabolism; D005799:Genes, Dominant; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008954:Models, Biological; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D000076205:Ras Homolog Enriched in Brain Protein; D012097:Repressor Proteins / Q000378:metabolism*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases; D013997:Time Factors; D000077004:Tuberous Sclerosis Complex 1 Protein; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins
chemical_list: D000903:Antibiotics, Antineoplastic; D009479:Neuropeptides; D011506:Proteins; C490211:RHEB protein, human; D000076205:Ras Homolog Enriched in Brain Protein; D012097:Repressor Proteins; C000624650:TSC1 protein, human; C000624653:TSC2 protein, human; D000077004:Tuberous Sclerosis Complex 1 Protein; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; D006160:Guanosine Triphosphate; D011494:Protein Kinases; C546842:MTOR protein, human; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; C448959:ribosomal protein S6 kinase, 70kD, polypeptide 2; D020558:GTP Phosphohydrolases; D020559:Monomeric GTP-Binding Proteins; D020123:Sirolimus