DNA- and RNA binding protein, involved in several nuclearprocesses. Essential pre-mRNA splicing factor required early inspliceosome formation and for splicing catalytic step II, probably as aheteromer with NONO. Binds to pre-mRNA in spliceosome C complex, andspecifically binds to intronic polypyrimidine tracts. Involved inregulation of signal-induced alternative splicing. During splicing ofPTPRC/CD45, a phosphorylated form is sequestered by THRAP3 from thepre-mRNA in resting T-cells; T-cell activation and subsequent reducedphosphorylation is proposed to lead to release from THRAP3 allowingbinding to pre-mRNA splicing regulatotry elements which represses exoninclusion. Interacts with U5 snRNA, probably by binding to a purine-rich sequence located on the 3' side of U5 snRNA stem 1b. May beinvolved in a pre-mRNA coupled splicing and polyadenylation process ascomponent of a snRNP-free complex with SNRPA/U1A. The SFPQ-NONOheteromer associated with MATR3 may play a role in nuclear retention ofdefective RNAs. SFPQ may be involved in homologous DNA pairing; invitro, promotes the invasion of ssDNA between a duplex DNA and producesa D-loop formation. The SFPQ-NONO heteromer may be involved in DNAunwinding by modulating the function of topoisomerase I/TOP1; in vitro, stimulates dissociation of TOP1 from DNA after cleavage and enhancesits jumping between separate DNA helices. The SFPQ-NONO heteromer bindsDNA. The SFPQ-NONO heteromer may be involved in DNAnon-homologous end joining (NHEJ) required for double-strand breakrepair and V (D) J recombination and may stabilize paired DNA ends; invitro, the complex strongly stimulates DNA end joining, binds directlyto the DNA substrates and cooperates with the Ku70/G22P1-Ku80/XRCC5 (Ku) dimer to establish a functional preligation complex. SFPQ isinvolved in transcriptional regulation. Functions as transcriptionalactivator. Transcriptional repression is mediated byan interaction of SFPQ with SIN3A and subsequent recruitment of histonedeacetylases (HDACs). The SFPQ-NONO-NR5A1 complex binds to the CYP17promoter and regulates basal and cAMP-dependent transcriptionalactivity. SFPQ isoform Long binds to the DNA binding domains (DBD) ofnuclear hormone receptors, like RXRA and probably THRA, and acts astranscriptional corepressor in absence of hormone ligands. Binds theDNA sequence 5'-CTGAGTC-3' in the insulin-like growth factor responseelement (IGFRE) and inhibits IGF-I-stimulated transcriptional activity. Regulates the circadian clock by repressing the transcriptionalactivator activity of the CLOCK-ARNTL/BMAL1 heterodimer. Required forthe transcriptional repression of circadian target genes, such as PER1, mediated by the large PER complex through histone deacetylation. Required for the assembly of nuclear speckles. Plays a role in the regulation of DNA virus-mediatedinnate immune response by assembling into the HDP-RNP complex, acomplex that serves as a platform for IRF3 phosphorylation andsubsequent innate immune response activation through the cGAS-STINGpathway. [1]

MSRDRFRSRGGGGGGFHRRGGGGGRGGLHDFRSPPPGMGLNQNRGPMGPGPGQSGPKPPIPPPPPHQQQQQPPPQQPPPQQPPPHQPPPHPQPHQQQQPPPPPQDSSKPVVAQGPGPAPGVGSAPPASSSAPPATPPTSGAPPGSGPGPTPTPPPAVTSAPPGAPPPTPPSSGVPTTPPQAGGPPPPPAAVPGPGPGPKQGPGPGGPKGGKMPGGPKPGGGPGLSTPGGHPKPPHRGGGEPRGGRQHHPPYHQQHHQGPPPGGPGGRSEEKISDSEGFKANLSLLRRPGEKTYTQRCRLFVGNLPADITEDEFKRLFAKYGEPGEVFINKGKGFGFIKLESRALAEIAKAELDDTPMRGRQLRVRFATHAAALSVRNLSPYVSNELLEEAFSQFGPIERAVVIVDDRGRSTGKGIVEFASKPAARKAFERCSEGVFLLTTTPRPVIVEPLEQLDDEDGLPEKLAQKNPMYQKERETPPRFAQHGTFEYEYSQRWKSLDEMEKQQREQVEKNMKDAKDKLESEMEDAYHEHQANLLRQDLMRRQEELRRMEELHNQEMQKRKEMQLRQEEERRRREEEMMIRQREMEEQMRRQREESYSRMGYMDPRERDMRMGGGGAMNMGDPYGSGGQKFPPLGGGGGIGYEANPGVPPATMSGSMMGSDMRTERFGQGGAGPVGGQGPRGMGPGTPAGYGRGREEYEGPNKKPRF