Evidence for Direct Activation of mTORC2 Kinase Activity by Phosphatidylinositol 3,4,5-Trisphosphate

• DOI: 10.1074/jbc.m110.195016
• Publication Date: 2011-02-11T04:40:55Z
• Authors: Xiaoqing Gan; Jiyong Wang; Bing Su; Dianqing Wu
• Keywords: Pleckstrin homology domain; mTORC2; Proto-Oncogene Proteins c-akt

mTORC2 (mammalian target of rapamycin complex 2) plays important roles in signal transduction by regulating an array downstream effectors, including protein kinase AKT. However, its regulation upstream regulators remains poorly characterized. Although phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) is known to regulate the phosphorylation AKT Ser(473), hydrophobic motif (HM) site, mTORC2, it not clear whether PtdIns(3,4,5)P(3) can directly activity. Here, we used two membrane-docked mutant proteins, one with and other without pleckstrin homology (PH) domain, as substrates for dissect HM cultured cells vitro assays. In HEK293T cells, insulin constitutively active mutants small GTPase H-Ras PI3K could induce both mutants, which was blocked inhibitor LY294002. Importantly, able stimulate immunoprecipitated mTOR2 complexes assay. vivo assays, containing PH domain appeared be a better substrate than domain. Therefore, these results suggest that via multiple mechanisms. One mechanisms activity mTORC2.