Involvement of phosphoinositide 3-kinase in insulin- or IGF-1-induced membrane ruffling.
Insulin, IGF-1 or EGF induce membrane ruffling through their respective tyrosine kinase receptors. To elucidate the molecular link between receptor activation and membrane ruffling, we microinjected phosphorylated peptides containing YMXM motifs or a mutant 85 kDa subunit of phosphoinositide (PI) 3-kinase (delta p85) which lacks a binding site for the catalytic 110 kDa subunit of PI 3-kinase into the cytoplasm of human epidermoid carcinoma KB cells. Both inhibited the association of insulin receptor substrate-1 (IRS-1) with PI 3-kinase in a cell-free system and also inhibited insulin- or IGF-1-induced, but not EGF-induced, membrane ruffling in KB cells. Microinjection of nonphosphorylated analogues, phosphorylated peptides containing the EYYE motif or wild-type 85 kDa subunit (Wp85), all of which did not inhibit the association of IRS-1 with PI 3-kinase in a cell-free system, did not inhibit membrane ruffling in KB cells. In addition, wortmannin, an inhibitor of PI 3-kinase activity, inhibited insulin- or IGF-1-induced membrane ruffling. These results suggest that the association of IRS-1 with PI 3-kinase followed by the activation of PI 3-kinase are required for insulin- or IGF-1-induced, but not for EGF-induced, membrane ruffling.
Kotani
K
K
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Yonezawa
K
K
Hara
K
K
Ueda
H
H
Kitamura
Y
Y
Sakaue
H
H
Ando
A
A
Chavanieu
A
A
Calas
B
B
Grigorescu
F
F
D000595:Amino Acid Sequence; D000730:Androstadienes / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D002474:Cell-Free System; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D008845:Microinjections; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases; D010748:Phosphopeptides / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D000077191:Wortmannin
D000730:Androstadienes; C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D010748:Phosphopeptides; D010750:Phosphoproteins; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D000077191:Wortmannin