Activates pre-mRNA splicing. May inhibit PP1 phosphatase activity. {ECO:0000269|PubMed:10593949, ECO:0000269|PubMed:11375989, ECO:0000269|PubMed:14640981}. This is the function of Ensembl gene identifier ENSG00000084463 (WBP11, WW domain binding protein 11).