Insulin stimulation of phosphorylation of the beta subunit of the insulin receptor. Formation of both phosphoserine and phosphotyrosine.

作者：Masato Kasuga, Yehiel Zick, D L Blith, Fredrik Karlsson, Hans-Ulrich Häring, C. Ronald Kahn · 发表于：Journal of Biological Chemistry · 年份：1982 · DOI：10.1016/s0021-9258(18)33955-3 · 被引用次数：439 · 研究领域：Metabolism, Diabetes, and Cancer、Pancreatic function and diabetes、Receptor Mechanisms and Signaling

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.