Insulin-like growth factor I stimulates tyrosine phosphorylation of p130(Cas), focal adhesion kinase, and paxillin. Role of phosphatidylinositol 3'-kinase and formation of a p130(Cas).Crk complex.
Addition of insulin growth factor-I (IGF-I) to quiescent Swiss 3T3 cells rapidly induced tyrosine phosphorylation of the p130Crk-associated substrate (p130(Cas)), a novel adaptor protein localized at focal adhesions. Half-maximal effect was obtained at 0. 6 nM. IGF-I also promoted the formation of a complex between p130(Cas) and c-Crk and elicited a parallel increase in the tyrosine phosphorylation of p125(Fak) and paxillin. IGF-I-induced p130(Cas), p125(Fak), and paxillin tyrosine phosphorylation could be dissociated from mitogen-activated protein kinase kinase, p70(S6K), and protein kinase C activation. In contrast, the structurally unrelated phosphatidylinositol 3-kinase inhibitors wortmannin and LY294002 markedly attenuated the increase in tyrosine phosphorylation of p130(Cas), p125(Fak), and paxillin induced by IGF-I. Cytochalasin D, which disrupts the network of actin microfilaments, completely prevented tyrosine phosphorylation of p130(Cas), p125(Fak), and paxillin and the formation of a p130(Cas). Crk complex in response to IGF-I. Thus, our results identified a phosphatidylinositol 3-kinase-dependent pathway that requires the integrity of the actin cytoskeleton to induce tyrosine phosphorylation of p130(Cas), p125(Fak), and paxillin in response to IGF-I and suggest that tyrosine phosphorylation of these focal adhesion proteins, together with the recruitment of c-Crk into a complex with p130(Cas), may play a novel role in IGF-I signal transduction.
Casamassima
A
A
Imperial Cancer Research Fund, Lincoln's Inn Fields, London WC2A 3PX, United Kingdom.
Rozengurt
E
E
D016475:3T3 Cells; D000199:Actins / Q000502:physiology; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002867:Chromones / Q000494:pharmacology; D050719:Crk-Associated Substrate Protein; D015638:Cytochalasin D / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases; D009025:Morpholines / Q000494:pharmacology; D051419:Paxillin; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000032:analysis; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014443:Tyrosine / Q000032:analysis; D000077191:Wortmannin
D000199:Actins; D000730:Androstadienes; D015815:Cell Adhesion Molecules; D002867:Chromones; D050719:Crk-Associated Substrate Protein; D015638:Cytochalasin D; D003598:Cytoskeletal Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D007334:Insulin-Like Growth Factor I; D020929:Mitogen-Activated Protein Kinase Kinases; D009025:Morpholines; D051419:Paxillin; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins; D019000:Phosphotyrosine; D011493:Protein Kinase C; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D050717:Retinoblastoma-Like Protein p130; D019893:Ribosomal Protein S6 Kinases; D014443:Tyrosine; D000077191:Wortmannin; C493842:Bcar1 protein, mouse; C496062:Pxn protein, mouse; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C496051:Ptk2 protein, mouse