Arginine methylation-dependent regulation of ASK1 signaling by PRMT1

Protein arginine methylation, catalyzed by protein arginine methyltransferases (PRMTs), is implicated in modulation of cellular processes including gene transcription. The role of PRMTs in the regulation of intracellular signaling pathways has remained obscure, however. We now show that PRMT1 methylates apoptosis signal-regulating kinase 1 (ASK1) at arginine residues 78 and 80 and thereby negatively regulates ASK1 signaling. PRMT1-mediated ASK1 methylation attenuated the H ₂O ₂-induced stimulation of ASK1, with this inhibitory effect of PRMT1 being abolished by replacement of arginines 78 and 80 of ASK1 with lysine. Furthermore, depletion of PRMT1 expression by RNA interference potentiated H ₂O ₂-induced stimulation of ASK1. PRMT1-mediated ASK1 methylation promoted the interaction between ASK1 and its negative regulator thioredoxin, whereas it abrogated the association of ASK1 with its positive regulator TRAF2. Moreover, PRMT1 depletion potentiated paclitaxel-induced ASK1 activation and apoptosis in human breast cancer cells. Together, our results indicate that arginine methylation of ASK1 by PRMT1 contributes to the regulation of stress-induced signaling that controls a variety of cellular events including apoptosis.