Csermely P, Kahn C R
Research Division, Joslin Diabetes Center, Boston, Massachusetts 02215.
Biochemistry. 1992 Oct 20;31(41):9940-6. doi: 10.1021/bi00156a012.
Insulin binding to its plasma membrane receptor stimulates a cascade of protein kinases and phosphatases which ultimately affects multiple processes in the membrane, cytosol, and nucleus of the cell, including transcription of specific genes. To gain insight into the relationship between the kinase cascade and the mechanism of insulin-induced nuclear events, we have studied the effect of insulin on the phosphorylation of DNA-binding nuclear proteins in differentiated NIH-3T3-F442A adipocytes. Insulin induced the phosphorylation of seven DNA-binding proteins: pp34, pp40, pp48, pp62, pp64, pp66, and pp72. The half-maximal response was observed at 10-30 min and reached its maximum at 60 min. The insulin-induced phosphorylation of each of these proteins was dose-dependent with ED50S of 2-10 nM. The phosphorylation of pp62, pp64, and pp72 took place on serine residues. On the basis of immunoprecipitation and immunoblotting experiments with anti-lamin antibodies, we found that the insulin-induced DNA-binding phosphoproteins pp62, pp64, pp66, and possibly pp48 were related to lamins A and C. The ED50 for insulin-stimulated lamin phosphorylation was approximately 10 nM, and phosphorylation was half-maximal at 30 min. The insulin-dependent phosphorylation of lamins and other DNA-binding proteins (pp34, pp40, and pp72) may play a mediatory role in the long-term effects of insulin.
胰岛素与其质膜受体结合会刺激一系列蛋白激酶和磷酸酶，最终影响细胞的膜、胞质溶胶和细胞核中的多个过程，包括特定基因的转录。为了深入了解激酶级联与胰岛素诱导的核事件机制之间的关系，我们研究了胰岛素对分化的NIH-3T3-F442A脂肪细胞中DNA结合核蛋白磷酸化的影响。胰岛素诱导了七种DNA结合蛋白的磷酸化：pp34、pp40、pp48、pp62、pp64、pp66和pp72。在10 - 30分钟时观察到半数最大反应，并在60分钟时达到最大值。这些蛋白各自的胰岛素诱导磷酸化呈剂量依赖性，半数有效剂量（ED50）为2 - 10 nM。pp62、pp64和pp72的磷酸化发生在丝氨酸残基上。基于用抗核纤层蛋白抗体进行的免疫沉淀和免疫印迹实验，我们发现胰岛素诱导的DNA结合磷蛋白pp62、pp64、pp66以及可能的pp48与核纤层蛋白A和C有关。胰岛素刺激核纤层蛋白磷酸化的ED50约为10 nM，磷酸化在30分钟时达到半数最大。核纤层蛋白和其他DNA结合蛋白（pp34、pp40和pp72）的胰岛素依赖性磷酸化可能在胰岛素的长期作用中起介导作用。
