PRMT4/CARM1 Antibody #4438

Protein arginine N-methyltransferase 4 (PRMT4), also known as coactivator-associated arginine methyltransferase 1 (CARM1), is a member of the protein arginine N-methyltransferase (PRMT) family of proteins, which catalyze the transfer of a methyl group from S-adenosylmethionine (AdoMet) to a guanidine nitrogen of arginine (1). There are two types of PRMT proteins. While both types catalyze the formation of mono-methyl arginine, type I PRMTs (PRMT1, 3, 4 and 6) add an additional methyl group to produce asymmetric di-methyl arginine and type II PRMTs (PRMT 5 and 7) produce symmetric di-methyl arginine (1). Mono-methyl arginine, but not di-methyl arginine, can be converted to citrulline through deimination performed by enzymes such as PADI4 (2). Most of the PRMTs methylate arginine residues found within glycine-arginine rich (GAR) domains of proteins, such as RGG, RG and RXR repeats (1). However, PRMT4/CARM1 and PRMT5 instead methylate arginine residues within PGM (proline-, glycine-, methionine-rich) motifs (3). PRMT4 methylates Arg2, 17 and 26 of histone H3 and cooperates synergistically with p300/CBP and p160 coactivators to enhance transcriptional activation by nuclear receptor proteins (4). In addition, PRMT4 methylates many non-histone proteins, including transcriptional coactivators (p300/CBP, SRC-3) (5,6,7,8), splicing factors (SmB, CA150, SAP49, UIC) (3), RNA binding proteins (PABP1, Sam68, HuD, HuR) (9,10,11), and thymocyte cyclic AMP-regulated phosphoprotein (TARPP) (12), suggesting additional functions in transcriptional regulation, mRNA processing and thymocyte maturation. Methylation of the splicing factor CA150 by PRMT4 facilitates an interaction with the Tudor domain of SMN, suggesting a role for PRMT4 in spinal muscular atrophy (3).