SFPQ
SFPQ (splicing factor proline and glutamine rich, also known as PSF and PPP1R140) is a multifunctional DNA- and RNA-binding protein of the nucleus. It is an essential pre-mRNA splicing factor that also contributes to transcriptional regulation, DNA repair and innate immune signalling. Browse Assay Genie's current range of SFPQ research reagents below, or read on for the biology behind the target.
SFPQ is a DNA- and RNA-binding protein involved in several nuclear processes. It is an essential pre-mRNA splicing factor, required early in spliceosome formation and for the second catalytic step of splicing, probably as a heteromer with NONO. It binds pre-mRNA in the spliceosome C complex, specifically binds intronic polypyrimidine tracts, and interacts with U5 snRNA. It is also implicated in the regulation of signal-induced alternative splicing: in resting T-cells a phosphorylated form is sequestered by THRAP3 away from PTPRC/CD45 pre-mRNA, and reduced phosphorylation after T-cell activation is proposed to release it so that it can repress exon inclusion.
Beyond splicing, SFPQ acts in transcription and DNA metabolism. It can function as a transcriptional activator, while repression involves an interaction with SIN3A and recruitment of histone deacetylases. The long isoform binds the DNA-binding domains of nuclear hormone receptors such as RXRA and acts as a corepressor in the absence of ligand. SFPQ also represses the CLOCK-BMAL1 heterodimer, helping to regulate the circadian clock, and is required for the assembly of nuclear speckles. In vitro, the SFPQ-NONO heteromer promotes DNA end joining with the Ku dimer, modulates topoisomerase I activity, and may contribute to double-strand break repair. SFPQ also assembles into the HDP-RNP complex, a platform for IRF3 phosphorylation in the cGAS-STING pathway during DNA virus-mediated innate immune responses.
The SFPQ gene is found in the HGNC groups for protein phosphatase 1 regulatory subunits and RNA binding motif containing proteins, which explains the alias PPP1R140. Its older name described it as polypyrimidine tract-binding protein-associated. NCBI Gene places the protein in chromatin, the nuclear matrix and paraspeckles, and links it to positive regulation of oxidative stress-induced intrinsic apoptotic signalling. The mouse ortholog is Sfpq.
SFPQ is required early in spliceosome formation and for splicing catalytic step II, making it a useful factor for studying splicing and alternative splicing.
SFPQ interacts with SIN3A and histone deacetylases and with nuclear hormone receptors, acting as both activator and corepressor of transcription.
The SFPQ-NONO heteromer stimulates DNA end joining with Ku and may contribute to double-strand break repair and homologous DNA pairing.
SFPQ represses CLOCK-BMAL1 activity and assembles into the HDP-RNP complex that promotes IRF3 phosphorylation through the cGAS-STING pathway.
SFPQ is an essential pre-mRNA splicing factor that binds intronic polypyrimidine tracts and acts early in spliceosome formation. It also regulates transcription, supports nuclear speckle assembly, takes part in DNA repair processes and contributes to innate immune signalling through the HDP-RNP complex.
SFPQ is also known as PSF and PPP1R140. Earlier HGNC names were splicing factor proline/glutamine rich (polypyrimidine tract-binding protein-associated) and splicing factor proline/glutamine-rich. UniProt describes a long isoform with distinct nuclear hormone receptor corepressor activity.
A mouse ortholog, Sfpq, is recorded for the human SFPQ gene. The source data do not give a rat ortholog. Researchers using an SFPQ antibody or other reagent in a given species should check the datasheet of any product for its validated reactivity.
Binding partners, splicing regulators and pathway proteins linked to SFPQ function, where pages are available.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P23246; product specifications from Assay Genie datasheets.