Plays a role in pre-mRNA splicing. Involved in both constitutive and alternative pre-mRNA splicing. May have a role in the recognition of the 3' splice site during the second step of splicing (By similarity). Interacts (via Arg/Ser-rich domain) with LUC7L3, RBM39 and RSF1. Shuttles between the nucleus and cytoplasm. Phosphorylated.