mTORC2 targets AGC kinases through Sin1-dependent recruitment
mTORC2 targets AGC kinases through Sin1-dependent recruitment
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DOI：
10.1042/bj20110678
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发表时间：
2011-10-15
影响因子：
4.1
通讯作者：
Parker, Peter J.
中科院分区：
文献类型：
--
作者：
Cameron, Angus J. M.;Linch, Mark D.;Parker, Peter J.
蛋白激酶TOR（雷帕霉素的靶标）是具有显著临床相关性的细胞生长和代谢的关键调节剂。在哺乳动物中，TOR通过两种不同的多蛋白复合物mTORC 1和mTORC 2（分别为哺乳动物TOR复合物1和2）发出信号，其亚基似乎定义了操作途径。雷帕霉素选择性靶向mTORC 1功能，特异性ATP竞争性激酶抑制剂的出现使得能够评估mTORC 1和mTORC 2双重阻断。然而，对mTORC 2组分的分子作用或靶向该途径的相对重要性知之甚少。在本研究中，我们已经确定了mTORC 2亚基Sin 1作为PKC（蛋白激酶C）激酶结构域的直接结合伴侣，并将相互作用映射到Sin 1的中心高度保守区域。利用PKC磷酸化的构象依赖性，我们证明mTORC 2是必不可少的急性启动的PKC。缺乏PKC相互作用结构域的Sin 1突变体的诱导表达，从mTORC 2置换内源性Sin 1并破坏PKC磷酸化。PK B（蛋白激酶B）/Akt磷酸化也被这些Sin 1突变体抑制，但不是mTORC 1底物p70（s6 k）（S6激酶），这提供了Sin 1作为募集mTORC 2靶标的选择性接头的证据。这种可诱导的选择性mTORC 2干预用于证明mTORC 2在三维培养中细胞增殖中的关键作用。
The protein kinase TOR (target of rapamycin) is a key regulator of cell growth and metabolism with significant clinical relevance. In mammals, TOR signals through two distinct multi-protein complexes, mTORC1 and mTORC2 (mammalian TOR complex 1 and 2 respectively), the subunits of which appear to define the operational pathways. Rapamycin selectively targets mTORC1 function, and the emergence of specific ATP-competitive kinase inhibitors has enabled assessment of dual mTORC1 and mTORC2 blockade. Little is known, however, of the molecular action of mTORC2 components or the relative importance of targeting this pathway. In the present study, we have identified the mTORC2 subunit Sin 1 as a direct binding partner of the PKC (protein kinase C) epsilon kinase domain and map the interaction to the central highly conserved region of Sin 1. Exploiting the conformational dependence for PKC phosphorylation, we demonstrate that mTORC2 is essential for acute priming of PKC. Inducible expression of Sin 1 mutants, lacking the PKC-interaction domain, displaces endogenous Sin 1 from mTORC2 and disrupts PKC phosphorylation. PKB (protein kinase B)/Akt phosphorylation is also suppressed by these Sin 1 mutants, but not the mTORC1 substrate p70(s6k) (S6 kinase), providing evidence that Sin 1 serves as a selectivity adaptor for the recruitment of mTORC2 targets. This inducible selective mTORC2 intervention is used to demonstrate a key role for mTORC2 in cell proliferation in three-dimensional culture.