INSULIN, OXYTOCIN, AND VASOPRESSIN STIMULATE PROTEIN KINASE-C ACTIVITY IN ADIPOCYTE PLASMA-MEMBRANES
INSULIN, OXYTOCIN, AND VASOPRESSIN STIMULATE PROTEIN KINASE-C ACTIVITY IN ADIPOCYTE PLASMA-MEMBRANES
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DOI：
10.1073/pnas.87.3.1052
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发表时间：
1990-02-01
影响因子：
11.1
通讯作者：
LONDOS, C
中科院分区：
文献类型：
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作者：
EGAN, JJ;SALTIS, J;LONDOS, C
用胰岛素、加压素或催产素孵育分离的大鼠脂肪细胞，可使质膜结合蛋白激酶C（PKC）活性增加100- 400%。PKC活性测定的程序，几乎是无背景的，从而允许在高度稀释的样品溶解膜的蛋白激酶活性测定。PKC活性的激素依赖性增加仅限于质膜。70 pM胰岛素对激酶的刺激为半最大值，激素效应迅速。催产素和加压素对PKC产生类似于胰岛素的作用，但加压素刺激的幅度表现出季节性变化。用佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）处理细胞导致细胞质中PKC活性的丧失和质膜活性的增加，表明酶的易位。通过活性测量，不可能确定胰岛素是否刺激激酶的易位。然而，针对PKC的多克隆抗体的质膜蛋白质印迹分析表明，至少有一些胰岛素刺激的PKC活性导致酶易位。
Incubation of isolated rat adipocytes with insulin, vasopressin, or oxytocin increased plasma membrane-bound protein kinase C (PKC) activity by 100-400%. PKC activity was assayed by a procedure that is virtually background-free, thus permitting assay of protein kinase activity in highly diluted samples of solubilized membranes. Hormone-dependent increases in PKC activity were limited to plasma membranes. Stimulation of the kinase was half-maximal with 70 pM insulin, and the hormone effect was rapid. Oxytocin and vasopressin produced effects on PKC similar to insulin, but the magnitude of the vasopressin stimulation exhibited seasonal variations. Treatment of cells with phorbol 12-myristate 13-acetate (PMA) resulted in a loss of PKC activity from the cytosol and a gain in plasma membrane activity, indicative of translocation of the enzyme. With activity measurements it was not possible to determine if insulin stimulated a translocation of the kinase. However, Western blot analysis of plasma membranes with polyclonal antibodies directed against PKC suggest that at least some of the insulin-stimulated PKC activity resulted from enzyme translocation.