Essential function of TORC2 in PKC and Akt turn motif phosphorylation, maturation and signalling.

Abstract

Protein kinase C (PKC) is involved in a wide array of cellular processes such as cell proliferation, differentiation and apoptosis. Phosphorylation of both turn motif (TM) and hydrophobic motif (HM) are important for PKC function. Here, we show that the mammalian target of rapamycin complex 2 (mTORC2) has an important function in phosphorylation of both TM and HM in all conventional PKCs, novel PKCepsilon as well as Akt. Ablation of mTORC2 components (Rictor, Sin1 or mTOR) abolished phosphorylation on the TM of both PKCalpha and Akt and HM of Akt and decreased HM phosphorylation of PKCalpha. Interestingly, the mTORC2-dependent TM phosphorylation is essential for PKCalpha maturation, stability and signalling. Our study demonstrates that mTORC2 is involved in post-translational processing of PKC by facilitating TM and HM phosphorylation and reveals a novel function of mTORC2 in cellular regulation.