Heterogeneous nuclear ribonucleoprotein (hnRNP) that associates with nascent pre-mRNAs, packaging them into hnRNP particles. The hnRNP particle arrangement on nascent hnRNA is non-random and sequence-dependent and serves to condense and stabilize the transcripts and minimize tangling and knotting. Packaging plays a role in various processes such as transcription, pre-mRNA processing, RNA nuclear export, subcellular location, mRNA translation and stability of mature mRNAs. Forms hnRNP particles with at least 20 other different hnRNP and heterogeneous nuclear RNA in the nucleus (PubMed:19099192). Involved in transport of specific mRNAs to the cytoplasm in oligodendrocytes and neurons: acts by specifically recognizing and binding the A2RE (21 nucleotide hnRNP A2 response element) or the A2RE11 (derivative 11 nucleotide oligonucleotide) sequence motifs present on some mRNAs, and promotes their transport to the cytoplasm (PubMed:9578590, PubMed:10567417). Specifically binds single-stranded telomeric DNA sequences, protecting telomeric DNA repeat against endonuclease digestion (PubMed:15659580). Also binds other RNA molecules, such as primary miRNA (pri-miRNAs): acts as a nuclear 'reader' of the N6-methyladenosine (m6A) mark by specifically recognizing and binding a subset of nuclear m6A-containing pri-miRNAs. Binding to m6A-containing pri-miRNAs promotes pri-miRNA processing by enhancing binding of DGCR8 to pri-miRNA transcripts. Involved in miRNA sorting into exosomes following sumoylation, possibly by binding (m6A)-containing pre-miRNAs. Acts as a regulator of efficiency of mRNA splicing, possibly by binding to m6A-containing pre-mRNAs. 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 (By similarity). Also plays a role in the activation of the innate immune response. Mechanistically, senses the presence of viral DNA in the nucleus, homodimerizes and is demethylated by JMJD6. In turn, translocates to the cytoplasm where it activates the TBK1-IRF3 pathway, leading to interferon alpha/beta production (By similarity). Homodimer; dimerization is required for nucleocytoplasmic translocation. Identified in the spliceosome C complex. Identified in a IGF2BP1-dependent mRNP granule complex containing untranslated mRNAs. Interacts with IGF2BP1. Interacts with C9orf72. Interacts with DGCR8. Interacts with TARDBP. Interacts with CKAP5. Interacts with TBK1. Interacts with STING1. Interacts with SRC (By similarity). Interacts with PPIA/CYPA (By similarity). Mainly localizes in the cytoplasm in neural cells. Localized in cytoplasmic mRNP granules containing untranslated mRNAs. Component of ribonucleosomes. Not found in the nucleolus. Found in exosomes following sumoylation. Additional isoforms seem to exist. In the brain, isoform A2 and isoform B1 are abundant in large ganglion-type neurons, such as Purkinje cells, and are less abundant in neighboring glia cells. Isoform A2 is more abundant than isoform B1 in brain. In testis, isoform A2 and isoform B1 are present in spermatogonia and spermatocytes, but not in spermatids or sperm. Isoform A2 is more abundant in the adrenal medulla than in the cortical cells. Isoform B1 is found in both adrenal medulla and cortical cells. Isoform A2 is more abundant than isoform B1 in the adrenal gland. Isoform A2 and isoform B1 are both detected in pancreas and kidney, and at lower levels in heart and lung. Isoform B1 is more abundant than isoform A2 in heart, lung and intestine (at protein level). Isoform A2b and isoform B1b are testis-specific. The disordered region, when incubated at high concentration, is able to polymerize into labile, amyloid-like fibers and form cross-beta polymerization structures, probably driving the formation of hydrogels. In contrast to irreversible, pathogenic amyloids, the fibers polymerized from LC regions disassemble upon dilution. A number of evidence suggests that formation of cross-beta structures by LC regions mediate the formation of RNA granules, liquid-like droplets, and hydrogels. Asymmetric dimethylation at Arg-266 constitutes the major methylation site (PubMed:24098712). According to a report, methylation affects subcellular location and promotes nuclear localization (PubMed:10772824). According to another report, methylation at Arg-266 does not influence nucleocytoplasmic shuttling (PubMed:24098712). Sumoylated in exosomes, promoting miRNAs-binding.