Scaffolding protein that specifically recognizes and binds dimethylarginine-containing proteins. In nucleus, acts as a coactivator: recognizes and binds asymmetric dimethylation on the 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. Component of mRNA stress granules. Interacts with FMR1, FXR1, FXR2, EWSR1, FUS, SERBP1, EEF1A1 and DDX3X or DDX3Y, and with the small nuclear ribonucleoprotein-associated proteins SNRPB and SNRPN. Interacts with 'Lys-48'-linked tetra-ubiquitin, but not with monoubiquitin or 'Lys-63'-linked ubiquitin chains. May interact with the exon junction complex (EJC) composed at least of CASC3, EIF4A3, MAGOH and RBM8A. Interacts with POLR2A (via the C-terminal domain (CTD)). Predominantly cytoplasmic. Associated with actively translating polyribosomes and with mRNA stress granules. Detected in heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. The Tudor domain specifically recognizes and binds asymmetric dimethylation of histone H3 'Arg-17' (H3R17me2a) and histones H4 'Arg-3', 2 tags for epigenetic transcriptional activation.