PMID: 2484434Jan 1, 1989Paper

Antiphosphotyrosine antibodies modulate insulin receptor kinase activity and insulin action

Cellular Signalling
R BallottiE Van Obberghen

Abstract

Insulin elicits the autophosphorylation of the beta-subunit of its receptor on tyrosine residues: this effect appears to be the earliest post-binding event involved in insulin action. In the present study we have raised highly specific antibodies to phosphotyrosine residues, and we have taken advantage of these antibodies to further evaluate the role of the insulin receptor tyrosine kinase in the generation of insulin's biological responses. Using a cell-free phosphorylation assay, we show here that these antibodies increase the tyrosine kinase activity of the receptor, and its phosphorylation on tyrosine residues. In contrast, the antibodies do not interfere with dephosphorylation of the insulin receptor. Introduction of the same antibodies in living Fao hepatoma cells enhances the effect of insulin on both glucose transport and aminoacid uptake. As a whole our data indicate that the insulin receptor kinase is involved in the generation of an early (glucose transport) and late (aminoacid uptake) response to insulin. Further, conformational changes in phosphotyrosine containing domains of the insulin receptor appear to modulate insulin's biological effects. Finally, the injection of antibodies in intact cells provides us with a...Continue Reading

References

Apr 1, 1986·The Biochemical Journal·S Gammeltoft, E Van Obberghen
Dec 28, 1983·Biochemical and Biophysical Research Communications·A KowalskiE Van Obberghen
Sep 15, 1983·Biochemical and Biophysical Research Communications·R BishopM J Weber

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