Fig. 3: PRMT5 catalyzes symmetric dimethylation of AKT1 at R391.
From: PRMT5-mediated arginine methylation activates AKT kinase to govern tumorigenesis
a, b IB analysis of WCLs and immunoprecipitation (IP) products derived from MCF7 cells. IgG was used as a negative control. c In vitro methylation of AKT1 in the presence of 3H-SAM. GST-AKT1, PRMT5-WT, and PRMT5-E444Q proteins were purified from HEK293 cells. d Sequence of the evolutionarily conserved residue R391 (red) in AKT. e In vitro methylation of AKT1-KD-WT and AKT1-KD-R391K in the presence of 3H-SAM. Recombinant GST-AKT1-WT and AKT1-KD-R391K proteins were purified from bacteria and HA-PRMT5/MEP50 proteins were immunopurified from HEK293 cells. f IB analysis of WCLs and IP products derived from MCF7 cells stably expressing AKT1-WT or R391K. Flag-PRMT5/MEP50 was transiently transfected into these cells. g Knockout of PRMT5 abrogates AKT1-R391 methylation. IB analysis of WCLs and IP products derived from PRMT5-knockout cells or control cells transfected with HA-AKT1. h Representative images of IHC staining for PRMT5 and R391-me2s in a breast cancer tissue array (n = 100 tissue specimens). Scale bar, 50 μm. i Quantification of cases with PRMT5 and R391-me2s staining (n = 100 tissue specimens). P-values were calculated using two-tailed χ2-test. Similar results were obtained in n ≥ 2 independent experiments in a–c and e–g. Uncropped immunoblots and statistical source data are provided in Source Data files.
