PRMT7 and cancer: The detailed characterization of these PRMT7-regulated mono-methylation revealed several features: PRMT7 preferentially methylates a consensus GAR (glycine and arginine) motif; PRMT7 often methylates multiple arginine sites in a given protein; phosphorylation sites are often found in the vicinity of PRMT7-regulated arginine methylation sites; PRMT7-regulated methylation sites and sequences in the vicinity are vulnerable to mutations in cancers.