May be required for progression through G1 and entry into S phase of cell growth. May play a regulatory role in pre-mRNA splicing. Autoregulates its own expression. Plays a role in constitutive splicing and can modulate the selection of alternative splice sites (By similarity). Found in a pre-mRNA splicing complex with SRSF4/SFRS4, SRSF5/SFRS5, SNRNP70, SNRPA1, SRRM1 and SRRM2 (By similarity). Interacts (via RS domain) with PHF5A (via N-terminus). Extensively phosphorylated on serine residues in the RS domain. Belongs to the splicing factor SR family.