在脂肪细胞中，t-SNARE 蛋白 syntaxin4 和 SNAP23，但不是 v-SNARE 蛋白 VAMP2，对于将 GLUT4 囊泡锚定在质膜上是不可或缺的。
The t-SNAREs syntaxin4 and SNAP23 but not v-SNARE VAMP2 are indispensable to tether GLUT4 vesicles at the plasma membrane in adipocyte.
机构信息
Division of Diabetes, Metabolism, and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan.
出版信息
Biochem Biophys Res Commun. 2010 Jan 15;391(3):1336-41. doi: 10.1016/j.bbrc.2009.12.045. Epub 2009 Dec 16.
SNARE proteins (VAMP2, syntaxin4, and SNAP23) have been thought to play a key role in GLUT4 trafficking by mediating the tethering, docking and subsequent fusion of GLUT4-containing vesicles with the plasma membrane. The precise functions of these proteins have remained elusive, however. We have now shown that depletion of the vesicle SNARE (v-SNARE) VAMP2 by RNA interference in 3T3-L1 adipocytes inhibited the fusion of GLUT4 vesicles with the plasma membrane but did not affect tethering of the vesicles to the membrane. In contrast, depletion of the target SNAREs (t-SNAREs) syntaxin4 or SNAP23 resulted in impairment of GLUT4 vesicle tethering to the plasma membrane. Our results indicate that the t-SNAREs syntaxin4 and SNAP23 are indispensable for the tethering of GLUT4 vesicles to the plasma membrane, whereas the v-SNARE VAMP2 is not required for this step but is essential for the subsequent fusion event.
SNARE 蛋白（VAMP2、syntaxin4 和 SNAP23）被认为在 GLUT4 转运中发挥关键作用，通过介导含 GLUT4 的囊泡与质膜的连接、对接和随后融合。然而，这些蛋白质的确切功能仍然难以捉摸。我们现在已经表明，在 3T3-L1 脂肪细胞中通过 RNA 干扰耗尽囊泡 SNARE（v-SNARE）VAMP2 会抑制 GLUT4 囊泡与质膜的融合，但不会影响囊泡与膜的连接。相比之下，耗尽靶 SNARE（t-SNARE）syntaxin4 或 SNAP23 会导致 GLUT4 囊泡与质膜的连接受损。我们的结果表明，t-SNAREs syntaxin4 和 SNAP23 对于 GLUT4 囊泡与质膜的连接是不可或缺的，而 v-SNARE VAMP2 对于这一步骤不是必需的，但对于随后的融合事件是必需的。
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