RNA recognition motif 1 and 2 in poly [ADP-ribose] polymerase PARP-10, RNA recognition motif 2 in PARP-14, RNA recognition motif in N-myc-interactor (Nmi), interferon-induced 35 kDa protein (IFP 35), RNA-binding protein 43 (RBM43) and similar proteins
This subfamily corresponds to the RRM1 and RRM2 of PARP-10, RRM2 of PARP-14, RRM of N-myc-interactor (Nmi), interferon-induced 35 kDa protein (IFP 35) and RNA-binding protein 43 (RBM43). PARP-10 is a novel oncoprotein c-Myc-interacting protein with poly(ADP-ribose) polymerase activity. It is localized to the nuclear and cytoplasmic compartments. In addition to PARP activity, PARP-10 is also involved in the control of cell proliferation by inhibiting c-Myc- and E1A-mediated cotransformation of primary cells. PARP-10 may also play a role in nuclear processes including the regulation of chromatin, gene transcription, and nuclear/cytoplasmic transport. PARP-10 contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two overlapping C-terminal domains composed of a glycine-rich region and a region with homology to catalytic domains of PARP enzymes (PARP domain). In addition, PARP-10 contains two ubiquitin-interacting motifs (UIM). PARP-14, also termed aggressive lymphoma protein 2, is a member of the B aggressive lymphoma (BAL) family of macrodomain-containing PARPs. Like PARP-10, PARP-14 also includes two RRMs at the N-terminus. Nmi, also termed N-myc and STAT interactor, is an interferon inducible protein that interacts with c-Myc, N-Myc, Max and c-Fos, and other transcription factors containing bHLH-ZIP, bHLH or ZIP domains. Besides binding Myc proteins, Nmi also associates with all the Stat family of transcription factors except Stat2. In response to cytokine (e.g. IL-2 and IFN-gamma) stimulation, Nmi can enhance Stat-mediated transcriptional activity through recruiting the Stat1 and Stat5 transcriptional coactivators, CREB-binding protein (CBP) and p300. IFP 35 is an interferon-induced leucine zipper protein that can specifically form homodimers. Distinct from known bZIP proteins, IFP 35 lacks a basic domain critical for DNA binding. In addition, IFP 35 may negatively regulate other bZIP transcription factors by protein-protein interaction. For instance, it can form heterodimers with B-ATF, a member of the AP1 transcription factor family. Both Nmi and IFP35 harbor one RRM. RBM43 is a putative RNA-binding protein containing one RRM, but its biological function remains unclear.