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). Could play an important role in development and differentiation in the spleen and thymus. Found in a pre-mRNA splicing complex with SRSF4/SFRS4, SRSF5/SFRS5, SNRNP70, SNRPA1, SRRM1 and SRRM2. Interacts (via RS domain) with PHF5A (via N-terminus) (By similarity). Highly expressed in spleen and thymus. By insulin and hepatectomy. Extensively phosphorylated on serine residues in the RS domain. Belongs to the splicing factor SR family.