Regulation of Glucose Transport by ROCK1 Differs from That of ROCK2 and Is Controlled by Actin Polymerization
Regulation of Glucose Transport by ROCK1 Differs from That of ROCK2 and Is Controlled by Actin Polymerization
复制标题
DOI：
10.1210/en.2011-1036
复制
发表时间：
2012-04-01
期刊：
影响因子：
4.8
通讯作者：
Kim, Young-Bum
中科院分区：
文献类型：
--
作者：
Chun, Kwang-Hoon;Araki, Kazushi;Kim, Young-Bum
Rho相关卷曲螺旋蛋白激酶（ROCK）1在调节全身葡萄糖稳态中的作用已有报道。然而，ROCK 1对脂肪细胞和肌肉细胞中胰岛素依赖性葡萄糖转运的细胞自主作用尚未阐明。为了确定ROCK 1在葡萄糖转运中的具体作用，对3 T3-L1脂肪细胞和L 6成肌细胞中的ROCK 1表达进行生物学调节。在这里，我们表明，小干扰RNA介导的ROCK 1消耗减少胰岛素诱导的脂肪细胞和成肌细胞中的葡萄糖转运，而腺病毒介导的ROCK 1表达以剂量依赖性方式增加这一点，表明ROCK 1是允许的葡萄糖转运。ROCK 1的抑制也损害了3 T3-L1脂肪细胞中葡萄糖转运蛋白4的易位。重要的是，当ROCK 1表达时，胰岛素对脂肪细胞葡萄糖转运的ED 50降低，导致对胰岛素的超敏反应。这些作用依赖于肌动蛋白细胞骨架重塑，因为肌动蛋白聚合的抑制剂显著降低了ROCK 1促进胰岛素刺激的葡萄糖转运的作用。与ROCK 2不同，ROCK 1与胰岛素受体底物（IRS）-1结合未被免疫沉淀法检测到，尽管细胞分级分离证明两种ROCK亚型均与IRS-1定位在低密度微粒体中。此外，胰岛素增加IRS-1酪氨酸612和丝氨酸632/635磷酸化的能力被ROCK 1抑制减弱。用丙氨酸取代IRS-1丝氨酸632/635减少了胰岛素刺激的磷脂酰肌醇3-激酶活化和3 T3-L1脂肪细胞中的葡萄糖转运，表明IRS-1的这些丝氨酸残基的磷酸化是ROCK 2同种型在体外的底物，对于胰岛素最大限度地刺激葡萄糖转运至关重要。我们的研究确定ROCK 1作为一个重要的积极调节胰岛素作用的葡萄糖转运脂肪细胞和肌肉细胞。（内分泌学153：1649-1662，2012）
A role of Rho-associated coiled-coil-containing protein kinase (ROCK) 1 in regulating whole-body glucose homeostasis has been reported. However, cell-autonomous effects of ROCK1 on insulin-dependent glucose transport in adipocytes and muscle cells have not been elucidated. To determine the specific role of ROCK1 in glucose transport directly, ROCK1 expression in 3T3-L1 adipocytes and L6 myoblasts was biologically modulated. Here, we show that small interfering RNA-mediated ROCK1 depletion decreased insulin-induced glucose transport in adipocytes and myoblasts, whereas adenovirus-mediated ROCK1 expression increased this in a dose-dependent manner, indicating that ROCK1 is permissive for glucose transport. Inhibition of ROCK1 also impaired glucose transporter 4 translocation in 3T3-L1 adipocytes. Importantly, the ED50 of insulin for adipocyte glucose transport was reduced when ROCK1 was expressed, leading to hypersensitivity to insulin. These effects are dependent on actin cytoskeleton remodeling, because inhibitors of actin polymerization significantly decreased ROCK1's effect to promote insulin-stimulated glucose transport. Unlike ROCK2, ROCK1 binding to insulin receptor substrate (IRS)-1 was not detected by immunoprecipitation, although cell fractionation demonstrated both ROCK isoforms localize with IRS-1 in low-density microsomes. Moreover, insulin's ability to increase IRS-1 tyrosine 612 and serine 632/635 phosphorylation was attenuated by ROCK1 suppression. Replacing IRS-1 serine 632/635 with alanine reduced insulin-stimulated phosphatidylinositol 3-kinase activation and glucose transport in 3T3-L1 adipocytes, indicating that phosphorylation of these serine residues of IRS-1, which are substrates of the ROCK2 isoform in vitro, are crucial for maximal stimulation of glucose transport by insulin. Our studies identify ROCK1 as an important positive regulator of insulin action on glucose transport in adipocytes and muscle cells. (Endocrinology 153: 1649-1662, 2012)