Characterization of the role of the Rab GTPase-activating protein AS160 in insulin-regulated GLUT4 trafficking
Characterization of the role of the Rab GTPase-activating protein AS160 in insulin-regulated GLUT4 trafficking
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DOI：
10.1074/jbc.m503897200
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发表时间：
2005-11-11
影响因子：
4.8
通讯作者：
James, DE
中科院分区：
文献类型：
--
作者：
Larance, M;Ramm, G;James, DE
胰岛素刺激葡萄糖转运蛋白GLUT 4从细胞内囊泡移位至质膜。在本研究中，我们进行了一个全面的蛋白质组学分析的亲和纯化的GLUT 4囊泡从3 T3-L1脂肪细胞，以发现潜在的GLUT 4运输的监管机构。除了先前确定的GLUT 4储存囊泡的组成部分，包括胰岛素调节的氨基肽酶和囊泡可溶性N-乙基马来酰亚胺因子附着蛋白（v-SNARE）VAMP 2，我们已经确定了三个新的Rab蛋白，Rab 10，Rab 11和Rab 14，GLUT 4囊泡。我们还发现，假定的Rab GTP酶激活蛋白AS 160（Akt底物160 kDa）与基础状态下的GLUT 4囊泡相关，并响应于胰岛素而解离。这种关联很可能是由胰岛素调节的氨基肽酶的胞质尾部介导的，该氨基肽酶在体外和体内均与AS 160相互作用。与AS 160在基础状态下的抑制作用一致，使用短发夹RNA降低脂肪细胞中AS 160的表达以胰岛素非依赖性方式增加GLUT 4的质膜水平。这些发现支持AS 160在胰岛素调节的GLUT 4运输中的重要作用。
Insulin stimulates the translocation of the glucose transporter GLUT4 from intracellular vesicles to the plasma membrane. In the present study we have conducted a comprehensive proteomic analysis of affinity-purified GLUT4 vesicles from 3T3-L1 adipocytes to discover potential regulators of GLUT4 trafficking. In addition to previously identified components of GLUT4 storage vesicles including the insulin-regulated aminopeptidase insulin-regulated aminopeptidase and the vesicle soluble N-ethylmaleimide factor attachment protein (v-SNARE) VAMP2, we have identified three new Rab proteins, Rab10, Rab11, and Rab14, on GLUT4 vesicles. We have also found that the putative Rab GTPase-activating protein AS160 (Akt substrate of 160 kDa) is associated with GLUT4 vesicles in the basal state and dissociates in response to insulin. This association is likely to be mediated by the cytosolic tail of insulin-regulated aminopeptidase, which interacted both in vitro and in vivo with AS160. Consistent with an inhibitory role of AS160 in the basal state, reduced expression of AS160 in adipocytes using short hairpin RNA increased plasma membrane levels of GLUT4 in an insulin-independent manner. These findings support an important role for AS160 in the insulin regulated trafficking of GLUT4.