STUDIES ON INSULIN-STIMULATED PHOSPHORYLATION OF ACETYL-COA CARBOXYLASE, ATP CITRATE LYASE AND OTHER PROTEINS IN RAT EPIDIDYMAL ADIPOSE-TISSUE - EVIDENCE FOR ACTIVATION OF A CYCLIC AMP-INDEPENDENT PROTEIN-KINASE
STUDIES ON INSULIN-STIMULATED PHOSPHORYLATION OF ACETYL-COA CARBOXYLASE, ATP CITRATE LYASE AND OTHER PROTEINS IN RAT EPIDIDYMAL ADIPOSE-TISSUE - EVIDENCE FOR ACTIVATION OF A CYCLIC AMP-INDEPENDENT PROTEIN-KINASE
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DOI：
10.1042/bj2180733
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发表时间：
1984-01-01
影响因子：
4.1
通讯作者：
DENTON, RM
中科院分区：
文献类型：
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作者：
BROWNSEY, RW;EDGELL, NJ;DENTON, RM
通过将来自[γ-32P]ATP的32P掺入通过十二烷基硫酸钠/聚丙烯酰胺凝胶电泳分离的磷蛋白中，研究了从先前在不存在或存在胰岛素的情况下温育的大鼠附睾脂肪组织制备的高速上清液级分中的蛋白激酶活性。经胰岛素处理的组织的上清液级分中的几种内源蛋白中 32P 的掺入显着增加。其中包括乙酰 CoA 羧化酶和 ATP 柠檬酸裂解酶（在暴露于胰岛素的脂肪细胞内表现出磷酸化增加），以及亚基 MW 78,000 和 43,000 的 2 个未知蛋白质。胰岛素增加的蛋白激酶活性与 cAMP 依赖性蛋白激酶不同，不依赖于 Ca2+，并且不受透析或凝胶过滤的明显影响。在由胰岛素处理的组织制备的高速上清液级分中，添加的纯化脂肪细胞乙酰辅酶A羧化酶和ATP柠檬酸裂合酶的磷酸化率也增加了60-90%。没有发现磷蛋白磷酸酶活性有任何持续变化的证据。胰岛素对乙酰辅酶A羧化酶、ATP柠檬酸裂合酶和其他表现出磷酸化增加的细胞内蛋白质的作用涉及细胞质中不依赖于cAMP的蛋白激酶活性的增加。讨论了这种增加反映了质膜易位的可能性，可能是在与胰岛素受体相关的蛋白酪氨酸激酶磷酸化之后。
Protein kinase activity in high speed supernatant fractions prepared from rat epididymal adipose tissue previously incubated in the absence or presence of insulin was investigated by following the incorporation of 32P from [.gamma.-32P]ATP into phosphoproteins separated by sodium dodecyl sulfate/polyacrylamide-gel electrophoresis. Incorporation of 32P into several endogenous proteins in the supernatant fractions from insulin-treated tissue was significantly increased. These included acetyl CoA carboxylase and ATP citrate lyase (which exhibit increased phosphorylation within fat cells exposed to insulin), together with 2 unknown proteins of subunit MW 78,000 and 43,000. The protein kinase activity increased by insulin was distinct from cAMP-dependent protein kinase, was not dependent on Ca2+ and was not appreciably affected by dialysis or gel filtration. The rate of phosphorylation of added purified fat cell acetyl CoA carboxylase and ATP citrate lyase was also increased by 60-90% in high speed supernatant fractions prepared from insulin-treated tissue. No evidence for any persistent changes in phosphoprotein phosphatase activity was found. Insulin action on acetyl-CoA carboxylase, ATP citrate lyase and other intracellular proteins exhibiting increased phosphorylation involves an increase in cAMP-independent protein kinase activity in the cytoplasm. The possibility that the increase reflects translocation from the plasma membrane, perhaps after phosphorylation by the protein tyrosine kinase associated with insulin receptors, is discussed.