RNA recognition motif 4 (RRM4) found in vertebrate heterogeneous nuclear ribonucleoprotein L (hnRNP-L)
This subgroup corresponds to the RRM4 of hnRNP-L, a higher eukaryotic specific subunit of human KMT3a (also known as HYPB or hSet2) complex required for histone H3 Lys-36 trimethylation activity. It plays both, nuclear and cytoplasmic, roles in mRNA export of intronless genes, IRES-mediated translation, mRNA stability, and splicing. hnRNP-L shows significant sequence homology with polypyrimidine tract-binding protein (PTB or hnRNP I). Both hnRNP-L and PTB are localized in the nucleus but excluded from the nucleolus. hnRNP-L is an RNA-binding protein with three RNA recognition motifs (RRMs), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain).