RNA-binding protein required for the formation of nuclear paraspeckles (PubMed:22416126). Binds to poly(A), poly(G) and poly(U) RNA homopolymers (PubMed:22416126). Regulates, cooperatively with NONO and SFPQ, androgen receptor-mediated gene transcription activity in Sertoli cell line (By similarity). Regulates the circadian clock by repressing the transcriptional activator activity of the CLOCK-BMAL1 heterodimer (By similarity). Plays a role in the regulation of DNA virus-mediated innate immune response by assembling into the HDP-RNP complex, a complex that serves as a platform for IRF3 phosphorylation and subsequent innate immune response activation through the cGAS-STING pathway (PubMed:28712728). {ECO:0000250|UniProtKB:Q8R326, ECO:0000269|PubMed:22416126, ECO:0000269|PubMed:28712728}. This is the function of PSPC1 (paraspeckle component 1, Ensembl gene identifier ENSG00000121390).