Kasuga, Zick, Blith, Karlsson, Haring, and Kahn. 1982. “Insulin Stimulation of Phosphorylation of the Beta Subunit of the Insulin Receptor. Formation of Both Phosphoserine and Phosphotyrosine”. J Biol Chem 257 (17): 9891-4.
Abstract
Rat hepatoma cells were labeled with [32P]orthophosphate and the insulin receptor subunits were identified by immunoprecipitation and sodium dodecyl sulfate-acrylamide gel electrophoresis. In the basal state, only the Mr = 95,000 (beta) subunit of the insulin receptor was phosphorylated. The covalent labeling with 32P of this subunit was stimulated about 3-fold by insulin (10(-6) M). This stimulation was due to an increase in the content of phosphoserine, the appearance of phosphotyrosine, and a possible increase in phosphothreonine as well. These results suggest phosphorylation of the insulin receptor at multiple sites is an early event in insulin action.
Last updated on 03/08/2023