Involved in the packaging of pre-mRNA into hnRNP particles, transport of poly(A) mRNA from the nucleus to the cytoplasm and modulation of splice site selection. Plays a role in the splicing of pyruvate kinase PKM by binding repressively to sequences flanking PKM exon 9, inhibiting exon 9 inclusion and resulting in exon 10 inclusion and production of the PKM M2 isoform. Binds to the IRES and thereby inhibits the translation of the apoptosis protease activating factor APAF1. May bind to specific miRNA hairpins. Identified in the spliceosome C complex. Identified in a IGF2BP1-dependent mRNP granule complex containing untranslated mRNAs. Interacts with SEPT6. Interacts with C9orf72. Interacts with KHDRBS1. Interacts with UBQLN2 (By similarity). Interacts with PPIA/CYPA (By similarity). Localized in cytoplasmic mRNP granules containing untranslated mRNAs. Shuttles continuously between the nucleus and the cytoplasm along with mRNA. Component of ribonucleosomes. Sumoylated.