Evidence for insulin-dependent activation of S6 and microtubule-associated protein-2 kinases via a human insulin receptor/v-ros hybrid

• Published in: The Journal of biological chemistry Vol. 265; no. 5; pp. 2713 - 2719
• Main Authors: BOULTON, T. G, GREGORY, J. S, SONG-MUH JONG, LU-HAI WANG, ELLIS, L, COBB, M. H
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15-02-1990
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Calcium-Calmodulin-Dependent Protein Kinases; Cell Line; Enzyme Activation; Enzymes and enzyme inhibitors; Fundamental and applied biological sciences. Psychology; Fusion Proteins, gag-onc - genetics; Fusion Proteins, gag-onc - metabolism; Insulin - pharmacology; Kinetics; microtubule-associated protein 2; Mutation; protein b68; Protein Kinases - metabolism; protein-tyrosine kinase S6; Receptor, Insulin - genetics; Receptor, Insulin - metabolism; Ribosomal Protein S6 Kinases; Ros protein; S6 kinase; Transfection; Transferases; v-ros; Phosphorylation; V-Onc gene; Stimulation; Insulin; Biological activity; Chromatography; Immunoprecipitation reaction; Cell line; Transfection; Protein kinase; Mutation; Hybrid gene; Chimera; Hormonal receptor
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)39860-6

The abilities of a series of six mutants of the human insulin receptor, an insulin receptor/v-ros hybrid (IR-ros) and the
P68gag-ros transforming protein to stimulate S6 protein kinase have been assessed. Insulin receptor mutants in which either
1 or 2 tyrosine residues have been replaced with phenylalanine (YF1, YF3) have lost some or all of the capacity to mediate
the activation of S6 kinase in response to insulin. None of the four mutants that contain deletions (spBam, spBamYF3, iBgl,
T-t) elicit an insulin-dependent stimulation of S6 kinase. A previous study of the IRros hybrid receptor demonstrated that
it was unable to cause either insulin-stimulated thymidine incorporation or glucose uptake (Ellis, L., Morgan, D. O., Jong,
S.-M., Wang, L.-H., Roth, R. A., and Rutter, W. J. (1987) Proc. Natl. Acad. Sci. U. S. A. 84, 5101-5105). In contrast, the
IRros chimera appears to mediate the activation of S6 protein kinase by insulin. In further evaluating the biological activities
of the IRros hybrid, we have examined its effects on a microtubule-associated protein-2 (MAP2) kinase that is thought to be
an early target in the cascade of reactions leading to increased S6 phosphorylation (Sturgill, T. W., Ray, L. B., Erickson,
E., and Maller, J. L. (1988) Nature 334, 715-718). We find that the IRros receptor stimulates the MAP2 protein kinase from
3- to 6-fold in insulin-treated cells, conferring more than a 30-fold increase in the insulin sensitivity of MAP2 kinase activation.