In vivo regulation of CrkII and CrkL proto-oncogenes in the uterus by insulin-like growth factor-I. Differential effects on tyrosine phosphorylation and association with paxillin.
Changes in CrkII and CrkL phosphorylation are associated with insulin-like growth factor receptor activation in cultured cells. We examined whether similar changes also occur following administration of recombinant human insulin-like growth factor-I to the intact animal. In female rats starved overnight, CrkL phosphorylation was significantly increased 12 min after insulin-like growth factor-I administration. Tyrosine phosphorylation of CrkII was not detectable in either control or treated animals. Paxillin, a 65-70-kDa phosphoprotein containing high affinity binding sites common for the Src homology 2 (SH2) domains of CrkII and CrkL, was observed in both CrkII and CrkL immunoprecipitates. Insulin-like growth factor-I treatment stimulated the association of CrkII with paxillin. In contrast, the same treatment resulted in the dissociation of the CrkL-paxillin complex. Similar effects of insulin-like growth factor-I treatment on the association of CrkL with tyrosine phosphorylated paxillin were observed in fibroblasts overexpressing CrkL. This study demonstrates that the activation of the insulin-like growth factor-I receptor induces changes in the tyrosine phosphorylation and protein-protein interactions of the Crk proteins in vivo. The different responses of CrkL and CrkII to insulin-like growth factor-I receptor activation suggest distinct roles for these two adapter proteins in signal transduction.
Butler
A A
AA
Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-1770, USA.
Blakesley
V A
VA
Koval
A
A
deJong
R
R
Groffen
J
J
LeRoith
D
D
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics*; D010052:Ovariectomy; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics*; D011518:Proto-Oncogene Proteins; D050737:Proto-Oncogene Proteins c-crk; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C082869:CRKL protein; C493872:Crk protein, rat; D003598:Cytoskeletal Proteins; D004967:Estrogens; C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; C526296:Irs1 protein, rat; D009687:Nuclear Proteins; D051419:Paxillin; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D050737:Proto-Oncogene Proteins c-crk; C496062:Pxn protein, mouse; C496063:Pxn protein, rat; D014443:Tyrosine; D007334:Insulin-Like Growth Factor I; D011494:Protein Kinases; D017526:Receptor, IGF Type 1