The adapter protein Grb10 associates preferentially with the insulin receptor as compared with the IGF-I receptor in mouse fibroblasts.
To identify receptor-associated proteins that may contribute to the specificity of insulin and IGF-I signaling responses, a mouse embryo library was screened using the yeast two-hybrid system. Multiple receptor-interactive clones encoding the SH2 domain of the adapter protein Grb10 were isolated. Subsequent cloning of the full-length Grb10 sequence from a ... mouse fat cDNA library defined a previously unknown Grb10 variant, that appears to be the predominant isoform in mouse tissues. Receptor-deficient R- cells (fibroblasts from mice with homologous disruption of the IGF-I receptor gene) and transfected R- cells expressing either insulin receptors (R-IR cells) or IGF-I receptors (R+ cells) were used to investigate the specificity of Grb10 interaction with the two related receptors. Hormone-activated insulin receptors in R-IR cells coprecipitated with three species, all recognized as Grb10 isoforms by specific Grb10 antibody. Under the same conditions, Grb10 was essentially undetectable in IGF-I receptor immunoprecipitates from stimulated R+ cells. Grb10 association with insulin receptors was maximal at 10 nM insulin stimulation and sustained from 5-10 min after hormone stimulation in R-IR cells. In conclusion, Grb10 interacts preferentially with insulin vs. IGF-I receptors in intact cells and, thus, may have a role in mediating insulin receptor-specific cellular responses.
Mesh Terms:
Animals, Blotting, Northern, Cloning, Molecular, DNA Primers, DNA, Complementary, Electrophoresis, Agar Gel, Electrophoresis, Polyacrylamide Gel, Fibroblasts, GRB10 Adaptor Protein, Gene Expression Regulation, Gene Library, Genetic Variation, Immunoblotting, Insulin, Isomerism, Lac Operon, Mice, Nucleic Acid Hybridization, Plasmids, Polymerase Chain Reaction, Precipitin Tests, Proteins, Receptor, IGF Type 1, Receptor, Insulin, Signal Transduction, Transfection, Yeasts
Animals, Blotting, Northern, Cloning, Molecular, DNA Primers, DNA, Complementary, Electrophoresis, Agar Gel, Electrophoresis, Polyacrylamide Gel, Fibroblasts, GRB10 Adaptor Protein, Gene Expression Regulation, Gene Library, Genetic Variation, Immunoblotting, Insulin, Isomerism, Lac Operon, Mice, Nucleic Acid Hybridization, Plasmids, Polymerase Chain Reaction, Precipitin Tests, Proteins, Receptor, IGF Type 1, Receptor, Insulin, Signal Transduction, Transfection, Yeasts
J. Clin. Invest.
Date: Mar. 01, 1997
PubMed ID: 9062339
View in: Pubmed Google Scholar
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