a serine-arginine-rich splicing regulatory protein. Plays a role in preventing exon skipping, ensuring the accuracy of splicing and regulating alternative splicing. Interacts with other spliceosomal components, via the RS domains, to form a bridge between the 5' and 3' splice site binding components, U1 snRNP and U2AF. Can stimulate binding of U1 snRNP to a 5'-splice-site-containing pre-mRNA. Extensively phosphorylated on serine residues in the serine-arginine rich region. Three splice variant isoforms have been described. ASF/SF2 splicing enhancer (ASE) which can specifically activate ASE-dependent splicing. Isoform ASF-2 and isoform ASF-3 act as splicing repressors. Note: This description may include information from UniProtKB.
Protein type: RNA binding protein; Spliceosome; RNA splicing
Biological Process: transcription from RNA polymerase II promoter; in utero embryonic development; RNA splicing; regulation of mRNA stability; nuclear mRNA 5'-splice site recognition; nuclear mRNA splicing, via spliceosome; regulation of translation; mRNA splice site selection; mRNA export from nucleus; regulation of nuclear mRNA splicing, via spliceosome; regulation of transcription, DNA-dependent; gene expression; mRNA 3'-end processing; mRNA processing; termination of RNA polymerase II transcription; cardiac muscle contraction
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.