RNA-binding protein which binds to intronic polypyrimidine tracts and mediates negative regulation of exons splicing. May antagonize in a tissue-specific manner the ability of NOVA1 to activate exon selection. In addition to its function in pre-mRNA splicing, plays also a role in the regulation of translation. {ECO:0000250|UniProtKB:Q91Z31, ECO:0000269|PubMed:11003644, ECO:0000269|PubMed:12667457}. [Isoform 5]: Reduced affinity for RNA. . This is the function of Ensembl gene identifier ENSG00000117569 (PTBP2, polypyrimidine tract binding protein 2).