Plays a role in constitutive splicing and can modulate the selection of alternative splice sites. Interacts (via RS domain) with PHF5A (via N-terminus) (By similarity). Found in a pre-mRNA splicing complex with SRSF4/SFRS4, SRSF5/SFRS5, SNRNP70, SNRPA1, SRRM1 and SRRM2. Extensively phosphorylated on serine residues in the RS domain. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the splicing factor SR family.