CARM1 (coactivator-associated arginine methyltransferase 1), also known as PRMT4 (protein arginine N-methyltransferase 4), is an enzyme (EC 2.1.1.125) encoded by the CARM1 gene found in human beings, as well as many other mammals. It has a polypeptide (L) chain type that is 348 residues long, and is made up of alpha helices and beta sheets. Its main function includes catalyzing the transfer of a methyl group from S-Adenosyl methionine to the side chain nitrogens of arginine residues within proteins to form methylated arginine derivatives and S-Adenosyl-L-homocysteine. CARM1 is a secondary coactivator through its association with p160 family (SRC-1, GRIP1, AIB) of coactivators. It is responsible for moving cells toward the inner cell mass in developing blastocysts.