Vesicle-associated membrane protein 2 plays a specific role in the insulin-dependent trafficking of the facilitative glucose transporter GLUT4 in 3T3-L1 adipocytes
Vesicle-associated membrane protein 2 plays a specific role in the insulin-dependent trafficking of the facilitative glucose transporter GLUT4 in 3T3-L1 adipocytes
复制标题
DOI：
10.1074/jbc.273.3.1444
复制
发表时间：
1998-01-16
影响因子：
4.8
通讯作者：
James, DE
中科院分区：
文献类型：
--
作者：
Martin, LB;Shewan, A;James, DE
囊泡相关膜蛋白2（VAMP 2）与胰岛素调节的脂肪细胞中GLUT 4的运输有关。已经提出VAMP 2与GLUT 4共定位于胞内后贮藏区室（Martin，S.，Tellam，J.，利文斯通，C.，斯洛特，J.W.，Gould，G. W.，和James，D. E.（1996）J. Cell Biol.134，625-635），这表明它可能发挥不同于内体v-SNARE的作用（可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体），如也在脂肪细胞中表达的纤维素泡蛋白。本研究检查了重组谷胱甘肽S-转移酶（GST）融合蛋白的作用，所述融合蛋白包括VAMP 1，VAMP 2，GST-VAMPS和GST-cellubrevin对胰岛素刺激的3 T3-L1脂肪细胞GLUT 4转位的抑制作用相似，GST-VAMPS抑制胰岛素刺激的GLUT 4转位约35%，而GST-VAMP 1和GST-cellubrevin则无此作用。对应于VAMP 2独特N末端的合成肽也以剂量依赖性方式抑制胰岛素刺激的GLUT 4转位，该肽对鸟苷5 ′-3-O-（硫代）三磷酸刺激的GLUT 4易位或对胰岛素刺激的GLUT 1易位均无影响。这些结果暗示GLUT 4和GLUT 1可能经历胰岛素刺激的从分开的细胞内区室向细胞表面的易位。将脂肪细胞与转铁蛋白-辣根过氧化物酶缀合物一起孵育以填充巡回内吞系统，之后将细胞与H2 O2和二氨基联苯胺一起孵育。这种处理完全阻断了胰岛素刺激的GLUT 1的运动，而在GLUT 4的情况下，向表面的运动被延迟，但在30分钟后仍达到与在胰岛素刺激的对照细胞中观察到的水平相似的水平。这些结果表明，VAMP 2的N末端在胰岛素依赖性的GLUT 4从其细胞内储存室向细胞表面的募集中起着独特的作用。
Vesicle-associated membrane protein 2 (VAMP2) has been implicated in the insulin-regulated trafficking of GLUT4 in adipocytes. It has been proposed that VAMP2 co-localizes with GLUT4 in a postendocytic storage compartment (Martin, S., Tellam, J., Livingstone, C., Slot, J. W., Gould, G. W., and James, D. E. (1996) J. Cell Biol. 134, 625-635), suggesting that it may play a role distinct from endosomal v-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) such as cellubrevin that are also expressed in adipocytes, The present study examines the effects of recombinant glutathione S-transferase (GST) fusion proteins encompassing the entire cytoplasmic tails of VAMP1, VAMP2, and cellubrevin on insulin-stimulated GLUT4 translocation in streptolysin O permeabilized 3T3-L1 adipocytes, GST-VAMPS inhibited insulin-stimulated GLUT4 trans location by similar to 35%, whereas GST-VAMP1 and GST-cellubrevin were without effect, A synthetic peptide corresponding to the unique N terminus of VAMP2 also inhibited insulin-stimulated GLUT4 translocation in a dose-dependent manner, This peptide had no effect on either guanosine 5'-3-O-(thio)triphosphate-stimulated GLUT4 translocation or on insulin-stimulated GLUT1 translocation, These results imply that GLUT4 and GLUT1 may undergo insulin stimulated translocation to the cell surface from separate intracellular compartments, To confirm this, adipocytes were incubated with a transferrin-horseradish peroxidase conjugate to fill the itinerant endocytic system after which cells were incubated with H2O2 and diaminobenzidine. This treat ment completely blocked insulin-stimulated movement of GLUT1, whereas in the case of GLUT4, movement to the surface was delayed but still reached similar levels to that observed in insulin-stimulated control cells after 30 min, These results suggest that the N terminus of VAMP2 plays a unique role in the insulin-dependent recruitment of GLUT4 from its intracellular storage compartment to the cell surface.