Arginine methyltransferase that methylates the guanidino nitrogens of arginyl residues in proteins such as STAT3, FBL, histone H4. Acts as a coactivator (with NCOA2) of the androgen receptor (AR)-mediated transactivation. Acts as a coactivator (with estrogen) of estrogen receptor (ER)-mediated transactivation. Enhances PGR, PPARG, RARA-mediated transactivation. May inhibit NF-kappa-B transcription and promote apoptosis. Represses E2F1 transcriptional activity (in a RB1-dependent manner). May be involved in growth regulation. L-arginyl-[protein] + 2 S-adenosyl-L-methionine = 2 H(+) + N(omega),N(omega)-dimethyl-L-arginyl-[protein] + 2 S-adenosyl-L-homocysteine Self-associates. Interacts with RB1 and E2F1 (By similarity). Interacts with NCOA6 coactivator. Interacts (via SH3 domain) with PRMT8. Interacts with AR. Interacts with NFKBIA. Interacts with ESR1, ESR2, PGR, PPARG, RARA, RXRA and THRB. Interacts with HNRNPUL1. Translocates from the cytoplasm to the nucleus, after hormone exposure. Excluded from nucleolus. Excluded from nucleolus. Excluded from nucleolus. Predominantly cytoplasmic. Widely expressed. Highly expressed in androgen target organs such as heart, prostate, skeletal muscle, ovary and spinal cord. Higher expression in breast cancer tissues. Higher expression in breast cancer tissues. Doesn't interact with ESR1. Higher expression in breast cancer tissues. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family.