Colca J R, DeWald D B, Pearson J D, Palazuk B J, Laurino J P, McDonald J M
J Biol Chem. 1987 Aug 25;262(24):11399-402.
Phosphorylation of cellular proteins is known to play an important role in mediating the metabolic effects of insulin in target cells. Here we show that exposure of intact adipocytes to physiological concentrations of insulin results in phosphorylation of the calcium receptor protein, calmodulin. The identity of the phosphorylated protein as being calmodulin in intact cells was demonstrated by two-dimensional electrophoresis, N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W7)-affinity chromatography, and positive staining with the Ca2+ binding protein stain Stains All. Phosphorylation of calmodulin occurred at physiological insulin concentrations with maximum stimulation (608 +/- 114% over basal) at 50 microunits/ml (3.3 X 10(-10) M) insulin. The 32Pi incorporated into calmodulin was stable to base, indicating that phosphotyrosine was involved and thus implicating the insulin-receptor tyrosine kinase as being responsible for its phosphorylation. The phosphorylation of calmodulin may represent an important component of the mechanism for intracellular signaling not only for insulin, but potentially for other physiological regulators of cellular metabolism.
已知细胞蛋白质的磷酸化在介导胰岛素对靶细胞的代谢作用中发挥重要作用。在此我们表明，完整的脂肪细胞暴露于生理浓度的胰岛素会导致钙受体蛋白钙调蛋白发生磷酸化。通过二维电泳、N-(6-氨基己基)-5-氯-1-萘磺酰胺（W7）亲和层析以及用Ca2+结合蛋白染色剂“全染剂”进行阳性染色，证实完整细胞中发生磷酸化的蛋白为钙调蛋白。钙调蛋白的磷酸化在生理胰岛素浓度下发生，在胰岛素浓度为50微单位/毫升（3.3×10−10 M）时刺激作用最大（比基础水平高608±114%）。掺入钙调蛋白的32Pi对碱稳定，表明涉及磷酸酪氨酸，因此提示胰岛素受体酪氨酸激酶负责其磷酸化。钙调蛋白的磷酸化可能不仅是胰岛素细胞内信号传导机制的一个重要组成部分，而且可能是细胞代谢其他生理调节因子的重要组成部分。
