PRAS40 and PRR5-Like Protein Are New mTOR Interactors that Regulate Apoptosis (original) (raw)
Figure 3
mTOR phosphorylates PRAS40 and PRR5L, and PRAS40 inhibits mTOR kinase activity. A. mTOR phosphorylates PRAS40 and PRR5L.
Kinase assays were performed using mTORC1 or mTORC2 immunopurified from HEK293 cells, and purified PRAS40, GST-PRR5L (PRR5L) or 4E-BP as substrates. Rapamycin (100 nM) and purified FKBP12 were added directly to the reaction. Both PRR5L and PRAS40 are phosphorylated in vitro by both mTORCs. Phosphorylation by mTORC1 was rapamycin-sensitive. B. PRAS40 inhibits mTORC1 kinase activity toward 4E-BP and PRAS40 itself. Kinase assays were performed using mTORC1 immunopurified from HEK293 cells, purified 4E-BP as a substrate, and increasing concentrations of PRAS40. PRAS40 inhibits mTORC1 autophosphorylation and mTORC1 phosphorylation of 4E-BP and PRAS40, in a concentration-dependent manner.