GLUT4 recycles via a trans-Golgi network (TGN) subdomain enriched in Syntaxins 6 and 16 but not TGN38:: Involvement of an acidic targeting motif
GLUT4 recycles via a trans-Golgi network (TGN) subdomain enriched in Syntaxins 6 and 16 but not TGN38:: Involvement of an acidic targeting motif
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DOI：
10.1091/mbc.e02-06-0315
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发表时间：
2003-03-01
影响因子：
3.3
通讯作者：
James, DE
中科院分区：
文献类型：
--
作者：
Shewan, AM;van Dam, EM;James, DE
胰岛素通过触发葡萄糖转运蛋白GLUT 4的胞吐作用刺激脂肪和肌肉细胞中的葡萄糖转运。为了确定GLUT 4的细胞内运输，我们研究了GLUT 4的表位标记版本从细胞表面的内化。GLUT 4迅速穿过内体系统到达核周位置。该核周GLUT 4区室不与内体标志物（内体抗原I蛋白、转铁蛋白）或TGN 38共定位，但显示与TGN靶（t）-可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）突触融合蛋白6和16显著重叠。这些结果证实了囊泡免疫分离。与突触融合蛋白6和16在GLUT 4运输中的作用一致，我们发现它们的表达在脂肪细胞分化期间显著上调，胰岛素刺激它们向细胞表面移动。GLUT 4在核内体和高尔基体网络之间的运输通过GLUT 4羧基端的酸性靶向基序进行调节，因为缺乏该基序的突变体保留在核内体中。我们的结论是，GLUT 4是迅速从细胞表面转运到一个子域的trans-Golgi网络，是丰富的t-SNARE的突触融合蛋白6和16和酸性靶向基序在C-末端尾部的GLUT 4在这个过程中起着重要的作用。
Insulin stimulates glucose transport in fat and muscle cells by triggering exocytosis of the glucose transporter GLUT4. To define the intracellular trafficking of GLUT4, we have studied the internalization of an epitope-tagged version of GLUT4 from the cell surface. GLUT4 rapidly traversed the endosomal system en route to a perinuclear location. This perinuclear GLUT4 compartment did not colocalize with endosomal markers (endosomal antigen I protein, transferrin) or TGN38, but showed significant overlap with the TGN target (t)-soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) Syntaxins 6 and 16. These results were confirmed by vesicle immunoisolation. Consistent with a role for Syntaxins 6 and 16 in GLUT4 trafficking we found that their expression was up-regulated significantly during adipocyte differentiation and insulin stimulated their movement to the cell surface. GLUT4 trafficking between endosomes and trans-Golgi network was regulated via an acidic targeting motif in the carboxy terminus of GLUT4, because a mutant lacking this motif was retained in endosomes. We conclude that GLUT4 is rapidly transported from the cell surface to a subdomain of the trans-Golgi network that is enriched in the t-SNAREs Syntaxins 6 and 16 and that an acidic targeting motif in the C-terminal tail of GLUT4 plays an important role in this process.