title: EGF-induced activation of 70-kDa S6 kinase in CHO cells expressing human EGF receptors.
abstract: We investigated epidermal growth factor (EGF)-induced activation of 85-kDa/110-kDa phosphatidylinositol (PI)-3-kinase and 70-kDa S6 kinase in Chinese hamster ovary cells expressing the human EGF receptor. EGF-induced activation of p70 S6 kinase was comparable to that induced by insulin, whereas that of PI-3-kinase in anti-phosphotyrosine immunoprecipitates was very small compared with insulin. Wortmannin, a p85/p110 PI-3-kinase inhibitor, inhibited EGF-induced activation of p70 S6 kinase in a dose-dependent manner. Given that several proteins homologous to catalytic subunit of p85/p110 PI-3-kinase have been identified and that wortmannin inhibits distinct form of PI-3-kinase, the present results suggest that wortmannin-sensitive kinases that resemble catalytic subunit of p85/p110 PI-3-kinase may participate in the signaling pathway from EGF receptors to p70 S6 kinase.
authors.affiliation: Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kido
authors.forename: Y
authors.initials: Y
authors.lastname: Okabayashi
authors.forename: T
authors.initials: T
authors.lastname: Okutani
authors.forename: Y
authors.initials: Y
authors.lastname: Sugimoto
authors.forename: K
authors.initials: K
authors.lastname: Sakaguchi
authors.forename: M
authors.initials: M
authors.lastname: Kasuga
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D007700:Kinetics; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D019893:Ribosomal Protein S6 Kinases; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D007328:Insulin; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D017346:Protein Serine-Threonine Kinases; D019893:Ribosomal Protein S6 Kinases; D000077191:Wortmannin