PHF5A
Description
The PHF5A (PHD finger protein 5A) is a protein-coding gene located on chromosome 22.
PHF5A is a component of the 17S U2 SnRNP complex, a large ribonucleoprotein complex involved in removing introns from transcribed pre-mRNAs. It plays a critical role in early spliceosome assembly and in recognizing the intron branch site during pre-mRNA splicing. Within the 17S U2 SnRNP complex, PHF5A is part of the SF3B subcomplex, essential for the formation of the 'A' complex through the stable binding of U2 snRNP to the branchpoint sequence in pre-mRNA. PHF5A also functions as a component of the minor spliceosome, responsible for splicing U12-type introns in pre-mRNAs. Additionally, PHF5A participates in RNA polymerase II elongation as part of the PAF1 complex (PAF1C). This complex is crucial for maintaining embryonic stem cell self-renewal and cellular reprogramming. PHF5A contributes to pluripotency by recruiting and stabilizing PAF1C on pluripotency gene loci and regulating the expression of these genes. It regulates the deposition of elongation-associated histone modifications, including dimethylated histone H3 'Lys-79' (H3K79me2) and trimethylated histone H3 'Lys-36' (H3K36me3), on PAF1C targets, self-renewal and pluripotency genes. PHF5A also regulates RNA polymerase II promoter-proximal pause release of the PAF1C targets and self-renewal genes, as well as the levels of elongating ( 'Ser-2' phosphorylated) RNA polymerase II in their gene bodies. Further, PHF5A regulates muscle specification in adult stem cells by stabilizing PAF1C in chromatin to promote myogenic differentiation. It acts as a transcriptional regulator by binding to the GJA1/Cx43 promoter and enhancing its up-regulation by ESR1/ER-alpha.
PHF5A is also known as INI, Rds3, SAP14b, SF3B7, SF3b14b, bK223H9.2.
