RNA recognition motif 1 (RRM1) found in the Spen (split end) protein family
This subfamily corresponds to the RRM1 domain in the Spen (split end) family which includes RNA binding motif protein 15 (RBM15), putative RNA binding motif protein 15B (RBM15B), and similar proteins found in Metazoa. RBM15, also termed one-twenty two protein 1 (OTT1), conserved in eukaryotes, is a novel mRNA export factor and component of the NXF1 pathway. It binds to NXF1 and serves as receptor for the RNA export element RTE. It also possesses mRNA export activity and can facilitate the access of DEAD-box protein DBP5 to mRNA at the nuclear pore complex (NPC). RNA-binding protein 15B (RBM15B), also known as one twenty-two 3 (OTT3), is a paralog of RBM15 and therefore has post-transcriptional regulatory activity. It is a nuclear protein sharing with RBM15 the association with the splicing factor compartment and the nuclear envelope as well as the binding to mRNA export factors NXF1 and Aly/REF. Members in this family belong- to the Spen (split end) protein family, which share a domain architecture comprising of three N-terminal RNA recognition motifs (RRMs), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal SPOC (Spen paralog and ortholog C-terminal) domain.