INSULIN-RESPONSIVE HUMAN ADIPOCYTES EXPRESS 2 GLUCOSE-TRANSPORTER ISOFORMS AND TARGET THEM TO DIFFERENT VESICLES
INSULIN-RESPONSIVE HUMAN ADIPOCYTES EXPRESS 2 GLUCOSE-TRANSPORTER ISOFORMS AND TARGET THEM TO DIFFERENT VESICLES
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DOI：
10.1210/jc.77.1.286
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发表时间：
1993-07-01
影响因子：
5.8
通讯作者：
OLEFSKY, JM
中科院分区：
文献类型：
--
作者：
PILCH, PF;WILKINSON, W;OLEFSKY, JM
我们的特点是胰岛素依赖性增加葡萄糖转运在人类脂肪细胞中使用亚细胞分级分离和特异性抗体的两种亚型的葡萄糖转运蛋白，在这些细胞中表达。从未经处理的人脂肪细胞中分离的质膜几乎仅含有葡萄糖转运蛋白的红细胞/GLUT 1亚型，而肌肉脂肪/GLUT 4转运蛋白亚型在静息细胞的细胞内微粒体膜中最丰富。在脂肪细胞暴露于胰岛素后，肌-脂肪同种型在质膜中显著增加，而红细胞同种型对胰岛素的反应几乎没有变化。因此，通过两种转运蛋白亚型的亲和标记证实，总胰岛素介导的质膜葡萄糖转运蛋白的增加必须是由于肌肉脂肪/GLUT 4转运蛋白的增加。这两种亚型存在于不同的囊泡群体中，如含有肌脂肪亚型的囊泡的免疫吸附所示，所述囊泡基本上缺乏红细胞转运蛋白。这些数据表明，胰岛素介导的人脂肪细胞中葡萄糖转运的增加是唯一含有肌肉脂肪葡萄糖转运蛋白同种型的囊泡易位的结果。
We have characterized the insulin-dependent increase in glucose transport in human adipocytes using subcellular fractionation and antibodies specific for the two isoforms of the glucose transporter that are expressed in these cells. Plasma membranes isolated from untreated human fat cells contain the erythroid/GLUT1 isoform of the glucose transporter almost exclusively whereas the muscle-fat/GLUT4 transporter isoform is most abundant in intracellular microsomal membranes in resting cells. After exposure of adipocytes to insulin, the muscle-fat isoform is dramatically increased in the plasma membrane whereas the erythroid isoform barely changes in response to insulin. Thus, the total insulin-mediated increase in plasma membrane glucose transporters, confirmed by affinity labeling of both transporter isoforms, must be due to the increase in the muscle-fat/GLUT4 transporter. The two isoforms exist in different vesicle populations as shown by immunoadsorption of the muscle fat isoform-containing vesicles which are essentially devoid of the erythroid transporter. These data indicate that the insulin-mediated increases in glucose transport in human fat cells is a result of the translocation of vesicles uniquely containing the muscle-fat glucose transporter isoform.