Sequence-specific RNA-binding protein which participates in the control of pre-mRNA splicing (By similarity). Can either activate or suppress exon inclusion. Acts additively with RBMX to promote exon 7 inclusion of the survival motor neuron SMN2. Activates the splicing of MAPT/Tau exon 10. Alters pre-mRNA splicing patterns by antagonizing the effects of splicing regulators, like RBMX. Binds to the AG-rich SE2 domain in the SMN exon 7 RNA. Binds to pre-mRNA (By similarity). Found in a pre-mRNA exonic splicing enhancer (ESE) complex with TRA2B/SFRS10, SNRNP70, SNRPA1 and SRRM1. Binds to A3 enhancer proteins SFRS4, SFRS5, SFRS6 and SFRS9. Interacts with CPSF6, RBMY1A1, RBMX, RNPS1 and phosphorylated SFRS13A (By similarity). Interacts with SAFB/SAFB1 (By similarity). Interacts with ILDR1 (via C-terminus) and ILDR2 (By similarity). Phosphorylated in the RS domains. Belongs to the splicing factor SR family.