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.

[2] It has a polypeptide (L) chain type that is 348 residues long, and is made up of alpha helices and beta sheets.

[3] 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.

In breast cancer, CARM1 methylates chromatin remodeling factor BAF155 to enhance tumor progression and metastasis.

CARM1-mediated MDH1 methylation reduces cellular NADPH level and sensitizes cells to oxidative stress, thereby suppressing cell proliferation and colony formation.