RNA-binding protein that acts as a regulator of alternative pre-mRNA splicing. Involved in apoptotic cell death through the regulation of the apoptotic factor BCL2L1 isoform expression. Modulates the ratio of proapoptotic BCL2L1 isoform S to antiapoptotic BCL2L1 isoform L mRNA expression. When overexpressed, stimulates proapoptotic BCL2L1 isoform S 5′-splice site (5′-ss) selection, whereas its depletion caused the accumulation of antiapoptotic BCL2L1 isoform L. Promotes BCL2L1 isoform S 5′-ss usage through the 5′-CGGGCA-3′ RNA sequence. Its association with LUC7L3 promotes U1 snRNP binding to a weak 5′ ss in a 5′-CGGGCA-3′-dependent manner. Binds to the exonic splicing enhancer 5′-CGGGCA-3′ RNA sequence located within exon 2 of the BCL2L1 pre-mRNA. Also involved in the generation of an abnormal and truncated splice form of SCN5A in heart failure.
