Involvement of phosphoinositide 3-kinase in insulin- or IGF-1-induced membrane ruffling

EMBO J. 1994 May 15;13(10):2313-21.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Androstadienes / pharmacology
  • Cell Membrane / drug effects
  • Cell Membrane / physiology*
  • Cell Membrane / ultrastructure
  • Cell-Free System
  • Dose-Response Relationship, Drug
  • Enzyme Activation / drug effects
  • Epidermal Growth Factor / pharmacology
  • Humans
  • Insulin / pharmacology*
  • Insulin Receptor Substrate Proteins
  • Insulin-Like Growth Factor I / pharmacology*
  • Microinjections
  • Molecular Sequence Data
  • Phosphatidylinositol 3-Kinases
  • Phosphopeptides / pharmacology
  • Phosphoproteins / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Tumor Cells, Cultured
  • Wortmannin


  • Androstadienes
  • IRS1 protein, human
  • Insulin
  • Insulin Receptor Substrate Proteins
  • Phosphopeptides
  • Phosphoproteins
  • Epidermal Growth Factor
  • Insulin-Like Growth Factor I
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Wortmannin