Caveolin-1 Loss of Function Accelerates Glucose Transporter 4 and Insulin Receptor Degradation in 3T3-L1 Adipocytes
Caveolin-1 Loss of Function Accelerates Glucose Transporter 4 and Insulin Receptor Degradation in 3T3-L1 Adipocytes
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DOI：
10.1210/en.2008-1520
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发表时间：
2009-08-01
期刊：
影响因子：
4.8
通讯作者：
Camps, Marta
中科院分区：
文献类型：
--
作者：
Gonzalez-Munoz, Elena;Lopez-Iglesias, Carmen;Camps, Marta
小窝是一种特殊类型的脂筏，由小窝蛋白的寡聚体稳定。小窝尤其富含脂肪细胞。在这里，我们分析了小窝蛋白-1基因敲除和小窝消融对脂肪细胞功能的影响。为此，我们使用慢病毒载体通过小干扰RNA方法获得了几个小凹蛋白-1表达降低(95%)的多克隆小鼠3T3-L1细胞系。通过慢病毒感染携带适当干扰RNA的慢病毒载体获得对照细胞系。Caveolin-1基因敲除的脂肪细胞的小凹数量急剧减少(减少95%)，霍乱毒素标记在动态质膜微区重组。Caveolin-1的缺失导致葡萄糖转运蛋白4(GLUT4)和胰岛素受体蛋白水平的特异性下降。这种减少并不是脂肪细胞分化的普遍缺陷或基因表达改变的结果，而是这些蛋白质更快的降解所致。Caveolin-1基因敲除的脂肪细胞显示胰岛素刺激的葡萄糖转运减少，胰岛素引发的GLUT4募集到细胞表面，以及胰岛素受体激活。总之，我们的数据表明，小窝蛋白-1功能的丧失通过降低稳定性和胰岛素受体和GLUT4的表达减少了最大胰岛素反应。我们认为小窝蛋白-1/小窝蛋白控制脂肪细胞中的胰岛素作用。(内分泌学150：3493-3502,2009)
Caveolae are a specialized type of lipid rafts that are stabilized by oligomers of caveolin protein. Caveolae are particularly enriched in adipocytes. Here we analyzed the effects of caveolin-1 knockdown and caveolae ablation on adipocyte function. To this end, we obtained several multiclonal mouse 3T3-L1 cell lines with a reduced expression of caveolin-1 (95% reduction) by a small interfering RNA approach using lentiviral vectors. Control cell lines were obtained by lentiviral infection with lentiviral vectors encoding appropriate scrambled RNAs. Caveolin-1 knockdown adipocytes showed a drastic reduction in the number of caveolae (95% decrease) and cholera toxin labeling was reorganized in dynamic plasma membrane microdomains. Caveolin-1 depletion caused a specific decrease in glucose transporter 4 (GLUT4) and insulin receptor protein levels. This reduction was not the result of a generalized defect in adipocyte differentiation or altered gene expression but was explained by faster degradation of these proteins. Caveolin-1 knockdown adipocytes showed reductions in insulin-stimulated glucose transport, insulin-triggered GLUT4 recruitment to the cell surface, and insulin receptor activation. In all, our data indicate that caveolin-1 loss of function reduces maximal insulin response through lowered stability and diminished expression of insulin receptors and GLUT4. We propose that caveolin-1/caveolae control insulin action in adipose cells. (Endocrinology 150: 3493-3502, 2009)