AKT1 dephosphorylation by PP2A-B56-beta,gamma

The protein phosphatase 2A (PP2A) complex containing a regulatory subunit B56 beta (PPP2R5B) or B56 gamma (PPP2R5C) dephosphorylates activated AKT1 on threonine residue T308 and serine residue S473, thus halting PI3K/AKT signaling (Rocher et al. 2007). Phosphatidylinositol-5-phosphate (PI5P) negatively regulates PP2A-mediated dephosphorylation of AKT1 by promoting, through an unknown mechanism, an inhibitory phosphorylation on tyrosine residue Y307 (Chen et al. 1992) of the catalytic subunit of PP2A (Ramel et al. 2009).

蛋白质磷酸酶2A（PP2A）复合物中的调节亚基B56β（PPP2R5B）或B56γ（PPP2R5C）能够去磷酸化激活的AKT1上的苏氨酸残基T308和丝氨酸残基S473，从而中止PI3K/AKT信号传导（Rocher等，2007）。磷脂酰肌醇-5-磷酸（PI5P）通过一种未知的机制，通过促进PP2A催化亚基上的酪氨酸残基Y307的抑制性磷酸化，负向调节PP2A介导的AKT1去磷酸化（Chen等，1992；Ramel等，2009）。