Specific role for p85/p110β in GTP-binding-protein-mediated activation of Akt
Specific role for p85/p110β in GTP-binding-protein-mediated activation of Akt
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DOI：
10.1042/bj20050671
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发表时间：
2005-12-15
影响因子：
4.1
通讯作者：
Hazeki, O
中科院分区：
文献类型：
--
作者：
Kubo, H;Hazeki, K;Hazeki, O
我们制备了同时表达IR（胰岛素受体）和A、R（A，腺苷受体）的CHO（中国仓鼠卵巢）细胞。用胰岛素或 PIA [N(6)-(2-苯基异丙基)腺苷]（一种特定的 A, R 激动剂）处理细胞，以 PI3K-（磷酸肌醇 3-激酶）依赖性方式增加细胞中的 Akt 活性。将 p110 转染到细胞中增强了 PIA 的作用，而对胰岛素的影响很小。引入可产生靶向 p110 beta 的 shRNA（短发夹 RNA）的 pH1 载体，消除了 PIA 诱导的 Akt 激活。相比之下，针对 p110 α 的 shRNA 探针不会削弱 PIA 的效果。 PIA 在 p110 α 缺陷细胞中的作用可被 Delta p85 和 β ARK-CT（β 肾上腺素受体激酶 C 末端肽）有效减弱。 Delta p85 衍生蛋白的两个 SH2 结构域具有点突变，但不会损害 PIA 作用。这些结果表明。酪氨酸磷酸化蛋白和 G beta gamma（GTP 结合蛋白的 beta gamma 亚基）对于完整细胞中 p110 beta 的特定功能是必需的。 p110 beta-middle（p110 beta的中间部分）可能在GPCR（GTP结合蛋白偶联受体）的信号接收中发挥重要作用，因为中间部分的转染会损害PIA敏感性。
We prepared CHO (Chinese hamster ovary) cells expressing both IR (insulin receptor) and A, R (A, adenosine receptor). Treatment of the cells with insulin or PIA [N(6)-(2-phenylisopropyl)adenosine], a specific A, R agonist increased Akt activity in the cells in a PI3K- (phosphoinositide 3-kinase) dependent manner. Transfection of p110 into the cells augmented the action of PIA with little effect on insulin. Introduction of a pH1 vector producing shRNA (short hairpin RNA) that targets p110 beta abolished PIA-induced Akt activation. By contrast, an shRNA probe targeting p110 alpha did not impair the effects of PIA. The effect of PIA in p110 alpha-deficient cells was attenuated effectively by both Delta p85 and beta ARK-CT (beta-adrenergic receptor kinase-C-terminal peptide). A Delta p85-derived protein possessing point mutations in its two SH2 domains did not impair PIA action. These results suggest that. tyrosine-phosphorylated proteins and G beta gamma (beta gamma subunits of GTP-binding protein) are necessary for the specific function of p110 beta in intact cells. The p110 beta-middle (middle part of p110 beta) may play an important role in signal reception from GPCRs (GTP-binding-protein-coupled receptor), because transfection of the middle part impaired PIA sensitivity.