RNA-binding protein involved in the regulation of smooth muscle cell differentiation and proliferation in the gastrointestinal system (PubMed:25064856). Binds NOG mRNA, the major inhibitor of the bone morphogenetic protein (BMP) pathway. Mediates an increase of NOG mRNA levels, thereby contributing to the negative regulation of BMP signaling pathway and promoting reversible dedifferentiation and proliferation of smooth muscle cells (By similarity). Acts as a pre- mRNA alternative splicing regulator (By similarity). Mediates ACTN1 and FLNB alternative splicing (By similarity). Likely binds to mRNA tandem CAC trinucleotide or CA dinucleotide motifs (PubMed:24860013). {ECO:0000250|UniProtKB:B5DFF2, ECO:0000250|UniProtKB:Q9W6I1, ECO:0000269|PubMed:24860013, ECO:0000269|PubMed:25064856}. This is the function of RBPMS2 (RNA binding protein, mRNA processing factor 2, ENSG00000166831).