PRMT1 methylate’s (mono & asymmetric dimethylation) the guanidino nitrogens of arginyl residues present in a glycine and arginine-rich domain (may methylate HNRNPA1 and histones) methylate’s SUPT5H. The PRMT1 protein functions as a histone methyltransferase specific for H4. PRMT1 is an essential factor in oncogenesis and is a potential novel therapeutic target in cancer. PRMT1-mediated methylation serves as a positive modulator of IR/IRS-1/PI3K pathway and glucose uptake in skeletal muscle cells. CAF1 is a new regulator of PRMT1-dependent arginine methylation. PRMT1 arginine-methylate’s MRE11 therefore it regulates the activity of MRE11-RAD50-NBS1 complex during the intra-S-phase DNA damage checkpoint response. PRMT1 plays a post-translationally part in regulating the transcriptional activity. PRMT1 is found predominantly in the cytoplasm, though a fraction of PRMT1 is located in the nucleus.