Protein arginine methyl transferases-3 and -5 increase cell surface expression of cardiac sodium channel

Abstract

The α-subunit of the cardiac voltage-gated sodium channel (NaV1.5) plays a central role in cardiomyocyte excitability. We have recently reported that NaV1.5 is post-translationally modified by arginine methylation. Here, we aimed to identify the enzymes that methylate NaV1.5, and to describe the role of arginine methylation on NaV1.5 function. Our results show that protein arginine methyl transferase (PRMT)-3 and -5 methylate NaV1.5 in vitro, interact with NaV1.5 in human embryonic kidney (HEK) cells, and increase NaV1.5 current density by enhancing NaV1.5 cell surface expression. Our observations are the first evidence of regulation of a voltage-gated ion channel, including calcium, potassium, sodium and TRP channels, by arginine methylation.

Keywords: AP; ArgMe; Arginine methylation; CFP or YFP; FRET; Förster resonance energy transfer; HEK; IP; Ion channel; L(I–II); Na(V)1.5; PRMT; Post-translational modification; S-(5′-adenosyl)-l-methionine; SAM; Sodium channel; action potential; arginine methylation; beats per minute; bmp; cardiac isoform of the voltage-gated sodium channel α subunit; co-IP; co-immunoprecipitation; cyan or yellow fluorescent protein; human embryonic kidney; immunoprecipitation; linker between domains DI and DII of Na(V)1.5; protein arginine methyltransferase.