Glut-4 is translocated to both caveolae and non-caveolar lipid rafts, but is partially internalized through caveolae in insulin-stimulated adipocytes  

作　　者：Taichang Yuan 

机构地区：[1]State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China, [2]Graduate School of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China

出　　处：《Cell Research》2007年第9期772-782,共11页细胞研究（英文版）

摘　　要：Caveolae and non-caveolar lipid rafts are two types of membrane lipid microdomains that play important roles in insulin-stimulated glucose uptake in adipocytes. In order to ascertain their specific functions in this process, caveolae were ablated by caveolin-1 RNA interference. In Cav-1 RNAi adipocytes, neither insulin-stimulated glucose uptake nor Glut-4 （glucose transporter 4） translocation to membrane lipid microdomains was affected by the ablation of caveolae. With a modified sucrose density gradient, caveolae and non-caveolar lipid rafts could be separated. In the wild-type 3T3- L l adipocytes, Glut-4 was found to be translocated into both caveolae and non-caveolar lipid rafts. However, in Cav1 RNAi adipocytes, Glut-4 was localized predominantly in non-caveolar lipid rafts. After the removal of insulin, caveolaelocalized Glut-4 was internalized faster than non-caveolar lipid raft-associated Glut-4. The internalization of Glut-4 from plasma membrane was significantly decreased in Cav-1 RNAi adipocytes. These results suggest that insulin-stimulated Glut-4 translocation and glucose uptake are caveolae-independent events. Caveolae play a role in the internalization of Glut-4 from plasma membrane after the removal of insulin.

关 键 词：Glut-4 translocation Glut-4 internalization lipid rafts CAVEOLAE sucrose density gradient flotation 

分 类 号：Q53[生物学—生物化学]