Scaffolding protein that specifically recognizes and binds dimethylarginine-containing proteins. In nucleus, acts as a core histone tails associated with transcriptional activation (H3R17me2a and H4R3me2a) and recruits proteins at these arginine- methylated loci. In cytoplasm, may play a role in the assembly and/or disassembly of mRNA stress granules and in the regulation of translation of target mRNAs by binding Arg/Gly-rich motifs (GAR) in dimethylarginine-containing proteins (By similarity).