Insulin induces tyrosine phosphorylation of Shc and stimulates Shc/GRB2 association in insulin-sensitive tissues of the intact rat.
Shc is a novel type of tyrosine-phosphorylated protein activated in response to a wide variety of polypeptide ligands. In this study, we used immunoprecipitation and immunoblotting to examine the effect of insulin on Shc tyrosine phosphorylation and Shc/GRB2 association in insulin-sensitive tissues of the intact rat. Following an infusion of insulin, Shc was tyrosine-phosphorylated in the liver, skeletal muscle, and adipose tissue in a time- and dose-dependent fashion, which peaked 5 min after exposure to the hormone and, except in the case of adipose tissue, returned to basal values after 15 min. There was coimmunoprecipitation of Shc and the insulin receptor after stimulation with insulin. Receptor tyrosine kinase activity toward Shc was also observed. Following an infusion of insulin, Shc was found to associate with GRB2. These results demonstrate that after stimulation of rat tissues with insulin, Shc binds to the insulin receptor, is tyrosine-phosphorylated, and subsequently associated with GRB2.
Departamento de Clínica Médica, FCM, UNICAMP, Campinas, SP, Brasil.
V
V
Páez-Espinosa
C R
CR
Carvalho
F
F
Alvarez-Rojas
L
L
Janeri
L A
LA
Velloso
A C
AC
Boschero
M J
MJ
Saad
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D051380:GRB2 Adaptor Protein; D015151:Immunoblotting; D007163:Immunosorbent Techniques; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D007328:Insulin; D011506:Proteins; D055765:Shc Signaling Adaptor Proteins; C528035:Shc1 protein, rat; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019000:Phosphotyrosine; D020794:Receptor Protein-Tyrosine Kinases; D011972:Receptor, Insulin