Sequence-specific RNA-binding protein which participates in the control of pre-mRNA splicing. 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, RNPS1 and phosphorylated SFRS13A (By similarity). Interacts with RBMX and SAFB/SAFB1 (PubMed:9671816, PubMed:19282290). Interacts with ILDR1 (via C-terminus) and ILDR2 (By similarity). Induced by reoxygenation following hypoxia and by exposure to silica. Repressed by interferon gamma, LPS and TPA. Phosphorylated in the RS domains. Belongs to the splicing factor SR family.