RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein 6 (RBM6)
This subgroup corresponds to the RRM2 of RBM6, also termed lung cancer antigen NY-LU-12, or protein G16, or RNA-binding protein DEF-3, which has been predicted to be a nuclear factor based on its nuclear localization signal. It shows high sequence similarity to RNA-binding protein 5 (RBM5 or LUCA15 or NY-REN-9). Both, RBM6 and RBM5, specifically bind poly(G) RNA. They contain two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two C2H2-type zinc fingers, a nuclear localization signal, and a G-patch/D111 domain. In contrast to RBM5, RBM6 has two additional unique domains: the decamer repeat occurring more than 20 times, and the POZ (poxvirus and zinc finger) domain. The POZ domain may be involved in protein-protein interactions and inhibit binding of target sequences by zinc fingers.