Insulin rapidly upregulates protein kinase Cδ gene expression in skeletal muscle
Insulin rapidly upregulates protein kinase Cδ gene expression in skeletal muscle
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DOI：
10.1016/j.cellsig.2005.04.004
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发表时间：
2006-02-01
影响因子：
4.8
通讯作者：
Sampson, SR
中科院分区：
文献类型：
--
作者：
Horovitz-Fried, M;Cooper, DR;Sampson, SR
我们实验室的最新研究表明，蛋白激酶C δ（PKC δ）对胰岛素诱导的骨骼肌葡萄糖转运至关重要，并且胰岛素快速刺激PKC δ活性骨骼肌。本研究的目的是研究PKC δ蛋白可用性的调节机制。在几种哺乳动物骨骼肌模型上进行了研究，并利用了分化肌管的全细胞裂解物。通过Western印迹技术测定PKC δ蛋白水平，通过北方印迹、RT-PCR和Real-Time RT-PCR测定PKC δ RNA水平。胰岛素刺激增加了全细胞裂解物中PKC δ蛋白水平。这种效应不是由于胰岛素抑制PKC δ蛋白降解速率所致。胰岛素也增加35 S-蛋氨酸掺入PKC δ在5-15分钟内。预处理细胞与转录或翻译抑制剂废除胰岛素诱导的PKC δ蛋白水平的增加。我们还发现，胰岛素迅速增加PKC δ RNA的水平，转录抑制剂消除了这种作用。胰岛素诱导的PKC δ表达增加并不因P13激酶或MAP激酶的抑制而降低，表明这些信号传导机制不参与，与PKC δ的胰岛素活化一致。对转染PKC δ启动子的细胞的研究表明，胰岛素在5分钟内激活了启动子。这项研究表明，PKC δ的表达可能在骨骼肌中的胰岛素作用过程中以快速的方式进行调节，并提高了PKC δ可能是胰岛素激活的立即早期反应基因的可能性。(c)2005年爱思唯尔公司All rights reserved.
Recent studies in our laboratories have shown that Protein Kinase C delta (PKC delta) is essential for insulin-induced glucose transport in skeletal muscle, and that insulin rapidly stimulates PKC delta activity skeletal muscle. The purpose of this study was to examine mechanisms of regulation of PKC delta protein availability. Studies were done on several models of mammalian skeletal muscle and utilized whole cell lysates of differentiated myotubes. PKC delta protein levels were determined by Western blotting techniques, and PKC delta RNA levels were determined by Northern blotting, RT-PCR and Real-Time RT-PCR. Insulin stimulation increased PKC delta protein levels in whole cell lysates. This effect was not due to an inhibition by insulin of the rate of PKC delta protein degradation. Insulin also increased 35 S-methionine incorporation into PKC delta within 5-15 min. Pretreatment of cells with transcription or translation inhibitors abrogated the insulin-induced increase in PKC delta protein levels. We also found that insulin rapidly increased the level of PKC delta RNA, an effect abolished by inhibitors of transcription. The insulin-induced increase in PKC delta expression was not reduced by inhibition of either P13 Kinase or MAP kinase, indicating that these signaling mechanisms are not involved, consistent with insulin activation of PKC delta. Studies on cells transfected with the PKC delta promoter demonstrate that insulin activated the promoter within 5 min. This study indicates that the expression of PKC delta may be regulated in a rapid manner during the course of insulin action in skeletal muscle and raise the possibility that PKC delta may be an immediate early response gene activated by insulin. (c) 2005 Elsevier Inc. All rights reserved.