IndraLab
Statements
"Overexpression of BTBD10 increased phosphorylation levels of Akts at both Thr(308) and Ser(473) while the reduction of the endogenous BTBD10 level resulted in a decrease in the phosphorylation levels of Akts. In vitro analysis indicated that BTBD10 bound to protein phosphatase 2A (PP2A) and inhibited dephosphorylation of Akts by PP2A."
"Regulation of phosphorylation of Thr-308 of Akt, cell proliferation, and survival by the B55alpha regulatory subunit targeting of the protein phosphatase 2A holoenzyme to Akt.|Phosphorylation of Akt at regulatory residues Thr-308 and Ser-473 leads to its full activation. The protein phosphatase 2A (PP2A) has long been known to negatively regulate Akt activity. The PP2A holoenzyme consists of the structural subunit (A), catalytic subunit (C), and a variable regulatory subunit (B)."
"Akt1 and akt2 are phosphorylated and activated by the protein kinase pdk1 at thr-308 or thr-309, respectively, in the activation t-loop, and further activation occurs through phosphorylation at ser-473 or ser-474, respectively. In this paper, we demonstrate that this is indeed the case, and report the purification and initial characterization of a 3 phosphoinositide-dependent protein kinase, pdk1, which activates pkb by phosphorylating it at thr308. Akt is directly phosphorylated and activated by pdk1. Akt/pkb activation requires the phosphorylation of thr308 in the activation loop by the phosphoinositide-dependent kinase 1 (pdk1)."
"Protein kinase B (PKB) was recently reported to be activated on the phosphorylation of Thr(308) by Ca(2+)/calmodulin-dependent protein kinase kinase alpha (CaM-kinase kinase alpha), suggesting that PKB was regulated through not only the phosphoinositide 3-kinase pathway but also the Ca(2+)/calmodulin protein kinase pathway."
"Together, these results suggest a mechanism in which 3' phosphoinositide lipid-dependent translocation of pkb to the plasma membrane promotes serine 473 phosphorylation, which is, in turn, necessary for pdk1-mediated phosphorylation of threonine 308 and, consequentially, full pkb activation."