RNPC3 serves as a bridging factor between the U11 and U12 snRNPs. It contains two RNA recognition motifs (RRMs), connected by a linker that includes a proline-rich region. It binds to the U11-associated 59K protein via its RRM1 and employs the RRM2 to bind hairpin III of the U12 small nuclear RNA (snRNA). The proline-rich region might be involved in protein-protein interactions [, ]. RBM41 contains only one RRM. Its biological function remains unclear.
