title: SHP-2 regulates cell growth by controlling the mTOR/S6 kinase 1 pathway.
abstract: Cell growth (accumulation in cell mass) ensues through the promotion of macromolecular biosynthesis. S 6 ribosomal kinase 1 (S6K1), which is activated by the mammalian target of rapamycin, is critical for cell growth. The early events that control S6K1 signaling remain unclear. Here we show that SHP-2 suppresses S6K1 activity under conditions of growth factor deprivation. We show that under conditions of growth factor deprivation, S6K1 activity was increased in fibroblasts lacking functional SHP-2 and in cells where knock down of SHP-2 expression was established by small interference RNA. Consistent with these findings, fibroblasts lacking functional SHP-2 exhibited increased cell size as compared with wild type cells. Growth factor deprivation reduces cellular energy, and the energy-sensing 5'-AMP-activated protein kinase (AMPK) negatively regulates S6K1. We found that SHP-2 promoted AMPK activity under conditions of growth factor deprivation (low energy), suggesting that SHP-2 negatively regulates S6K1 via an AMPK-dependent pathway. These results implicate SHP-2 as an early mediator in the S6K1 signaling pathway to limit cell growth in low energy states.
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Christina I
authors.initials: CI
authors.lastname: Zito
authors.forename: Hui
authors.initials: H
authors.lastname: Qin
authors.forename: John
authors.initials: J
authors.lastname: Blenis
authors.forename: Anton M
authors.initials: AM
authors.lastname: Bennett
mesh_terms: D000263:Adenylate Kinase / Q000502:physiology; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology; D049109:Cell Proliferation; D054736:Elongation Factor 2 Kinase; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D051379:Mice; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D011494:Protein Kinases / Q000502:physiology*; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000502:physiology*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D011494:Protein Kinases; C546843:mTOR protein, mouse; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; C448901:ribosomal protein S6 kinase, 70kD, polypeptide 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517690:Eef2k protein, mouse; D054736:Elongation Factor 2 Kinase; D000263:Adenylate Kinase; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse