Protein arginine methyltransferase 9 (PRMT9)

Protein arginine methyltransferase 9 (PRMT9) is a type II methyltransferase enzyme in the protein arginine methyltransferase family, encoded by the PRMT9 gene in humans. It catalyzes symmetric dimethylation of arginine residues on target proteins, with SF3B2 (splicing factor 3B subunit 2) identified as its primary substrate via methylation of arginine 508[1][2][3]. PRMT9 regulates pre-mRNA alternative splicing in neurons and has implications for cognitive function and synapse development; loss-of-function mutations in PRMT9 cause intellectual disability in humans and mice by dysregulating alternative splicing[2][3]. It also participates in innate immune regulation by methylating MAVS and suppressing spontaneous antiviral signaling, helping to maintain cellular homeostasis in the absence of viral infection[4][5]. PRMT9 is structurally distinct within the PRMT family, possessing two AdoMet-binding motifs and three N-terminal tetratricopeptide repeats[4][7]. Its direct link to disease is emerging, with roles in neurodevelopmental disorders, antiviral defense, and likely cancer biology. No clinically approved inhibitors or interacting drugs have been described as of current literature, and targeted therapy remains an area of research. Safety concerns with PRMT9 modulation relate primarily to risks of aberrant splicing and immune response alteration[1][2][5].

Other names

PRMT9PRMT10 (secondary, less common)protein arginine N-methyltransferase 9

Inhibition of arginine methylation (drug action would be predicted, but specific inhibitors are not described in available sources); Modulation of immune responses via interference with MAVS methylation