RNA recognition motif (RRM) found in eukaryotic translation initiation factor 4B (eIF-4B) and similar proteins; This subfamily corresponds to the RRM of eIF-4B, a multi-domain RNA-binding protein that has been primarily implicated in promoting the binding of 40S ribosomal subunits to mRNA during translation initiation. It contains two RNA-binding domains; the N-terminal well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), binds the 18S rRNA of the 40S ribosomal subunit and the C-terminal basic domain (BD), including two arginine-rich motifs (ARMs), binds mRNA during initiation, and is primarily responsible for the stimulation of the helicase activity of eIF-4A. eIF-4B also contains a DRYG domain (a region rich in Asp, Arg, Tyr, and Gly amino acids) in the middle, which is responsible for both, self-association of eIF-4B and binding to the p170 subunit of eIF3. Additional research indicates that eIF-4B can interact with the poly(A) binding protein (PABP) in mammalian cells, which can stimulate both, the eIF-4B-mediated activation of the helicase activity of eIF-4A and binding of poly(A) by PABP. eIF-4B has also been shown to interact specifically with the internal ribosome entry sites (IRES) of several picornaviruses which facilitate cap-independent translation initiation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  94 PPYTAFLGNLPYDVSEESIRDFFRGLAISAVRLPREpNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRVDIADQ 173
Cdd:cd12402    1 PPYTAYLGNLPYDVTEDDIEDFFRGLNISSVRLPRE-NGPGRLRGFGYVEFEDRESLIQALSLNEESLKNRRIRVDVAGQ 79

                 ..
gi 528482848 174 SN 175
Cdd:cd12402   80 AQ 81

RNA recognition motif (RRM) found in eukaryotic translation initiation factor 4B (eIF-4B) and similar proteins; This subfamily corresponds to the RRM of eIF-4B, a multi-domain RNA-binding protein that has been primarily implicated in promoting the binding of 40S ribosomal subunits to mRNA during translation initiation. It contains two RNA-binding domains; the N-terminal well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), binds the 18S rRNA of the 40S ribosomal subunit and the C-terminal basic domain (BD), including two arginine-rich motifs (ARMs), binds mRNA during initiation, and is primarily responsible for the stimulation of the helicase activity of eIF-4A. eIF-4B also contains a DRYG domain (a region rich in Asp, Arg, Tyr, and Gly amino acids) in the middle, which is responsible for both, self-association of eIF-4B and binding to the p170 subunit of eIF3. Additional research indicates that eIF-4B can interact with the poly(A) binding protein (PABP) in mammalian cells, which can stimulate both, the eIF-4B-mediated activation of the helicase activity of eIF-4A and binding of poly(A) by PABP. eIF-4B has also been shown to interact specifically with the internal ribosome entry sites (IRES) of several picornaviruses which facilitate cap-independent translation initiation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  94 PPYTAFLGNLPYDVSEESIRDFFRGLAISAVRLPREpNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRVDIADQ 173
Cdd:cd12402    1 PPYTAYLGNLPYDVTEDDIEDFFRGLNISSVRLPRE-NGPGRLRGFGYVEFEDRESLIQALSLNEESLKNRRIRVDVAGQ 79

                 ..
gi 528482848 174 SN 175
Cdd:cd12402   80 AQ 81

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 528482848   99 FLGNLPYDVSEESIRDFFRGLA-ISAVRLPRepNNPERLKGFGYAEFDDIESLLRAL-SLNEENLGNRRIR 167
Cdd:pfam00076   2 FVGNLPPDTTEEDLKDLFSKFGpIKSIRLVR--DETGRSKGFAFVEFEDEEDAEKAIeALNGKELGGRELK 70

mucin-associated surface protein (MASP); Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848 429 TGSESSHPKGSRCRDDEHSENEVFSGQESEPISPTSPSP---TSNQGSLPLKVM---PAPPPKENAWAKRSLGGGANEKE 502
Cdd:PTZ00459 136 SSAESISPSGSRELNVNLTQTEVEGKKETDKNTPAVENPlttGNGENTLPAGIVegnPSPPPPQDGIHSREQDGEGTTSE 215

                         90       100       110
                 ....*....|....*....|....*....|
gi 528482848 503 AppSANAPINKSAPRPNRSADERESGKDEN 532
Cdd:PTZ00459 216 G--QKNVPLPETAATPQSHHDKGSEGTGED 243

RNA recognition motif (RRM) found in eukaryotic translation initiation factor 4B (eIF-4B) and similar proteins; This subfamily corresponds to the RRM of eIF-4B, a multi-domain RNA-binding protein that has been primarily implicated in promoting the binding of 40S ribosomal subunits to mRNA during translation initiation. It contains two RNA-binding domains; the N-terminal well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), binds the 18S rRNA of the 40S ribosomal subunit and the C-terminal basic domain (BD), including two arginine-rich motifs (ARMs), binds mRNA during initiation, and is primarily responsible for the stimulation of the helicase activity of eIF-4A. eIF-4B also contains a DRYG domain (a region rich in Asp, Arg, Tyr, and Gly amino acids) in the middle, which is responsible for both, self-association of eIF-4B and binding to the p170 subunit of eIF3. Additional research indicates that eIF-4B can interact with the poly(A) binding protein (PABP) in mammalian cells, which can stimulate both, the eIF-4B-mediated activation of the helicase activity of eIF-4A and binding of poly(A) by PABP. eIF-4B has also been shown to interact specifically with the internal ribosome entry sites (IRES) of several picornaviruses which facilitate cap-independent translation initiation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  94 PPYTAFLGNLPYDVSEESIRDFFRGLAISAVRLPREpNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRVDIADQ 173
Cdd:cd12402    1 PPYTAYLGNLPYDVTEDDIEDFFRGLNISSVRLPRE-NGPGRLRGFGYVEFEDRESLIQALSLNEESLKNRRIRVDVAGQ 79

                 ..
gi 528482848 174 SN 175
Cdd:cd12402   80 AQ 81

RNA recognition motif (RRM) found in Saccharomyces cerevisiae nucleolar protein 6 (Nop6) and similar proteins; This subfamily corresponds to the RRM of Nop6, also known as Ydl213c, a component of 90S pre-ribosomal particles in yeast S. cerevisiae. It is enriched in the nucleolus and is required for 40S ribosomal subunit biogenesis. Nop6 is a non-essential putative RNA-binding protein with two N-terminal putative nuclear localisation sequences (NLS-1 and NLS-2) and an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It binds to the pre-rRNA early during transcription and plays an essential role in pre-rRNA processing.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 528482848  96 YTAFLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNpERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12400    1 YILFVGNLPYDTTAEDLKEHFKKAGePPSVRLLTDKKT-GKSKGCAFVEFDNQKALQKALKLHHTSLGGRKINV 73

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins; This subfamily corresponds to the RRM domain of CSTF2, its tau variant and eukaryotic homologs. CSTF2, also termed cleavage stimulation factor 64 kDa subunit (CstF64), is the vertebrate conterpart of yeast mRNA 3'-end-processing protein RNA15. It is expressed in all somatic tissues and is one of three cleavage stimulatory factor (CstF) subunits required for polyadenylation. CstF64 contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a CstF77-binding domain, a repeated MEARA helical region and a conserved C-terminal domain reported to bind the transcription factor PC-4. During polyadenylation, CstF interacts with the pre-mRNA through the RRM of CstF64 at U- or GU-rich sequences within 10 to 30 nucleotides downstream of the cleavage site. CSTF2T, also termed tauCstF64, is a paralog of the X-linked cleavage stimulation factor CstF64 protein that supports polyadenylation in most somatic cells. It is expressed during meiosis and subsequent haploid differentiation in a more limited set of tissues and cell types, largely in meiotic and postmeiotic male germ cells, and to a lesser extent in brain. The loss of CSTF2T will cause male infertility, as it is necessary for spermatogenesis and fertilization. Moreover, CSTF2T is required for expression of genes involved in morphological differentiation of spermatids, as well as for genes having products that function during interaction of motile spermatozoa with eggs. It promotes germ cell-specific patterns of polyadenylation by using its RRM to bind to different sequence elements downstream of polyadenylation sites than does CstF64. The family also includes yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins. RNA15 is a core subunit of cleavage factor IA (CFIA), an essential transcriptional 3'-end processing factor from Saccharomyces cerevisiae. RNA recognition by CFIA is mediated by an N-terminal RRM, which is contained in the RNA15 subunit of the complex. The RRM of RNA15 has a strong preference for GU-rich RNAs, mediated by a binding pocket that is entirely conserved in both yeast and vertebrate RNA15 orthologs.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  96 YTAFLGNLPYDVSEESIRDFFR--GLAISaVRL--PREPNNPerlKGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDI 170
Cdd:cd12398    1 RSVFVGNIPYDATEEQLKEIFSevGPVVS-FRLvtDRETGKP---KGYGFCEFRDAETALSAVrNLNGYELNGRPLRVDF 76

                 .
gi 528482848 171 A 171
Cdd:cd12398   77 A 77

RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain); The RRM motif is probably diagnostic of an RNA binding protein. RRMs are found in a variety of RNA binding proteins, including various hnRNP proteins, proteins implicated in regulation of alternative splicing, and protein components of snRNPs. The motif also appears in a few single stranded DNA binding proteins. The RRM structure consists of four strands and two helices arranged in an alpha/beta sandwich, with a third helix present during RNA binding in some cases The C-terminal beta strand (4th strand) and final helix are hard to align and have been omitted in the SEED alignment The LA proteins have an N terminal rrm which is included in the seed. There is a second region towards the C terminus that has some features characteriztic of a rrm but does not appear to have the important structural core of a rrm. The LA proteins are one of the main autoantigens in Systemic lupus erythematosus (SLE), an autoimmune disease.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 528482848   99 FLGNLPYDVSEESIRDFFRGLA-ISAVRLPRepNNPERLKGFGYAEFDDIESLLRAL-SLNEENLGNRRIR 167
Cdd:pfam00076   2 FVGNLPPDTTEEDLKDLFSKFGpIKSIRLVR--DETGRSKGFAFVEFEDEEDAEKAIeALNGKELGGRELK 70

RNA recognition motif 2 (RRM2) found in yeast protein gar2 and similar proteins; This subfamily corresponds to the RRM2 of yeast protein gar2, a novel nucleolar protein required for 18S rRNA and 40S ribosomal subunit accumulation. It shares similar domain architecture with nucleolin from vertebrates and NSR1 from Saccharomyces cerevisiae. The highly phosphorylated N-terminal domain of gar2 is made up of highly acidic regions separated from each other by basic sequences, and contains multiple phosphorylation sites. The central domain of gar2 contains two closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The C-terminal RGG (or GAR) domain of gar2 is rich in glycine, arginine and phenylalanine residues.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 528482848  99 FLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNpERLKGFGYAEFDDIESLLRALSLNE-ENLGNRRIRVD 169
Cdd:cd12448    2 FVGNLPFSATQDALYEAFSQHGsIVSVRLPTDRET-GQPKGFGYVDFSTIDSAEAAIDALGgEYIDGRPIRLD 73

RNA recognition motif 1 (RRM1) found in squamous cell carcinoma antigen recognized by T-cells 3 (SART3) and similar proteins; This subfamily corresponds to the RRM1 of SART3, also termed Tat-interacting protein of 110 kDa (Tip110), an RNA-binding protein expressed in the nucleus of the majority of proliferating cells, including normal cells and malignant cells, but not in normal tissues except for the testes and fetal liver. It is involved in the regulation of mRNA splicing probably via its complex formation with RNA-binding protein with a serine-rich domain (RNPS1), a pre-mRNA-splicing factor. SART3 has also been identified as a nuclear Tat-interacting protein that regulates Tat transactivation activity through direct interaction and functions as an important cellular factor for HIV-1 gene expression and viral replication. In addition, SART3 is required for U6 snRNP targeting to Cajal bodies. It binds specifically and directly to the U6 snRNA, interacts transiently with the U6 and U4/U6 snRNPs, and promotes the reassembly of U4/U6 snRNPs after splicing in vitro. SART3 contains an N-terminal half-a-tetratricopeptide repeat (HAT)-rich domain, a nuclearlocalization signal (NLS) domain, and two C-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGLA-ISAVRLPRepNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRVD 169
Cdd:cd12391    1 TVFVSNLDYSVPEDKIREIFSGCGeITDVRLVK--NYKGKSKGYCYVEFKDEESAQKALKLDRQPVEGRPMFVS 72

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein (hnRNP) H protein family, epithelial splicing regulatory proteins (ESRPs), Drosophila RNA-binding protein Fusilli, RNA-binding protein 12 (RBM12) and similar proteins; The family includes RRM domains in the hnRNP H protein family, G-rich sequence factor 1 (GRSF-1), ESRPs (also termed RBM35), Drosophila Fusilli, RBM12 (also termed SWAN), RBM12B, RBM19 (also termed RBD-1) and similar proteins. The hnRNP H protein family includes hnRNP H (also termed mcs94-1), hnRNP H2 (also termed FTP-3 or hnRNP H'), hnRNP F and hnRNP H3 (also termed hnRNP 2H9), which represent a group of nuclear RNA binding proteins that are involved in pre-mRNA processing. GRSF-1 is a cytoplasmic poly(A)+ mRNA binding protein which interacts with RNA in a G-rich element-dependent manner. It may function in RNA packaging, stabilization of RNA secondary structure, or other macromolecular interactions. ESRP1 (also termed RBM35A) and ESRP2 (also termed RBM35B) are epithelial-specific RNA binding proteins that promote splicing of the epithelial variant of fibroblast growth factor receptor 2 (FGFR2), ENAH (also termed hMena), CD44 and CTNND1 (also termed p120-Catenin) transcripts. Fusilli shows high sequence homology to ESRPs. It can regulate endogenous FGFR2 splicing and functions as a splicing factor. The biological roles of both, RBM12 and RBM12B, remain unclear. RBM19 is a nucleolar protein conserved in eukaryotes. It is involved in ribosome biogenesis by processing rRNA. In addition, it is essential for preimplantation development. Members in this family contain 2~6 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 528482848 102 NLPYDVSEESIRDFFRGLAISA--VRLPREPNNpeRLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12254    6 GLPFSATEEDIRDFFSGLDIPPdgIHIVYDDDG--RPTGEAYVEFASEEDAQRALRRHKGKMGGRYIEV 72

RNA recognition motif (RRM) domain [Translation, ribosomal structure and biogenesis];

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 528482848  99 FLGNLPYDVSEESIRDFFRGL-AISAVRLPREPNNpERLKGFGYAEFDDIESLLRALS-LNEENLGNRRIRVDIA 171
Cdd:COG0724    5 YVGNLPYSVTEEDLRELFSEYgEVTSVKLITDRET-GRSRGFGFVEMPDDEEAQAAIEaLNGAELMGRTLKVNEA 78

RNA recognition motif 1 (RRM1) found in Arabidopsis thaliana phragmoplastin interacting protein 1 (PHIP1) and similar proteins; This subfamily corresponds to the RRM1 of PHIP1. A. thaliana PHIP1 and its homologs represent a novel class of plant-specific RNA-binding proteins that may play a unique role in the polarized mRNA transport to the vicinity of the cell plate. The family members consist of multiple functional domains, including a lysine-rich domain (KRD domain) that contains three nuclear localization motifs (KKKR/NK), two RNA recognition motifs (RRMs), and three CCHC-type zinc fingers. PHIP1 is a peripheral membrane protein and is localized at the cell plate during cytokinesis in plants. In addition to phragmoplastin, PHIP1 interacts with two Arabidopsis small GTP-binding proteins, Rop1 and Ran2. However, PHIP1 interacted only with the GTP-bound form of Rop1 but not the GDP-bound form. It also binds specifically to Ran2 mRNA.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 528482848  98 AFLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNPeRLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12271    1 VYVGGIPYYSTEAEIRSYFSSCGeVRSVDLMRFPDSG-NFRGIAFITFKTEEAAKRALALDGEMLGNRFLKV 71

RNA recognition motif (RRM) found in eukaryotic RNA-binding protein 25 and similar proteins; This subfamily corresponds to the RRM of RBM25, also termed Arg/Glu/Asp-rich protein of 120 kDa (RED120), or protein S164, or RNA-binding region-containing protein 7, an evolutionary-conserved splicing coactivator SRm160 (SR-related nuclear matrix protein of 160 kDa, )-interacting protein. RBM25 belongs to a family of RNA-binding proteins containing a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), at the N-terminus, a RE/RD-rich (ER) central region, and a C-terminal proline-tryptophan-isoleucine (PWI) motif. It localizes to the nuclear speckles and associates with multiple splicing components, including splicing cofactors SRm160/300, U snRNAs, assembled splicing complexes, and spliced mRNAs. It may play an important role in pre-mRNA processing by coupling splicing with mRNA 3'-end formation. Additional research indicates that RBM25 is one of the RNA-binding regulators that direct the alternative splicing of apoptotic factors. It can activate proapoptotic Bcl-xS 5'ss by binding to the exonic splicing enhancer, CGGGCA, and stabilize the pre-mRNA-U1 snRNP through interaction with hLuc7A, a U1 snRNP-associated factor.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  97 TAFLGNLPYDVSEESIRDFFR--GLAISAVRLpREPNNpeRLKGFGYAEFDDIESLLRALS-LNEENLGNRRIRVDIadq 173
Cdd:cd12446    2 TVFVGNIPDDVSDDFIRQLLEkcGKVLSWKRV-QDPSG--KLKAFGFCEFEDPEGALRALRlLNGLELGGKKLLVKV--- 75

                 ....*..
gi 528482848 174 sNDKERD 180
Cdd:cd12446   76 -DAKTKK 81

RNA recognition motif 2 (RRM2) found in Nicotiana sylvestris chloroplastic 33 kDa ribonucleoprotein (NsCP33) and similar proteins; The family includes NsCP33, Arabidopsis thaliana chloroplastic 31 kDa ribonucleoprotein (CP31A) and mitochondrial glycine-rich RNA-binding protein 2 (AtGR-RBP2). NsCP33 may be involved in splicing and/or processing of chloroplast RNA's. AtCP31A, also called RNA-binding protein 1/2/3 (AtRBP33), or RNA-binding protein CP31A, or RNA-binding protein RNP-T, or RNA-binding protein cp31, is required for specific RNA editing events in chloroplasts and stabilizes specific chloroplast mRNAs, as well as for normal chloroplast development under cold stress conditions by stabilizing transcripts of numerous mRNAs under these conditions. CP31A may modulate telomere replication through RNA binding domains. AtGR-RBP2, also called AtRBG2, or glycine-rich protein 2 (AtGRP2), or mitochondrial RNA-binding protein 1a (At-mRBP1a), plays a role in RNA transcription or processing during stress. It binds RNAs and DNAs sequence with a preference to single-stranded nucleic acids. AtGR-RBP2 displays strong affinity to poly(U) sequence. It exerts cold and freezing tolerance, probably by exhibiting an RNA chaperone activity during the cold and freezing adaptation process. Some members in this family contain two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the second RRM motif.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 528482848  99 FLGNLPYDVSEESIRDFFRGL-AISAVRL--PREPNnpeRLKGFGYAEFDDIESLLRALS-LNEENLGNRRIRVDIA 171
Cdd:cd21608    3 YVGNLSWDTTEDDLRDLFSEFgEVESAKVitDRETG---RSRGFGFVTFSTAEAAEAAIDaLNGKELDGRSIVVNEA 76

RNA recognition motif 1 (RRM1) found in vertebrate RNA-binding protein 39 (RBM39) and similar proteins; This subfamily corresponds to the RRM1 of RNA-binding protein 39 (RBM39), RNA-binding protein 23 (RBM23) and similar proteins. RBM39 (also termed HCC1) is a nuclear autoantigen that contains an N-terminal arginine/serine rich (RS) motif and three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). An octapeptide sequence called the RS-ERK motif is repeated six times in the RS region of RBM39. Although the cellular function of RBM23 remains unclear, it shows high sequence homology to RBM39 and contains two RRMs. It may possibly function as a pre-mRNA splicing factor.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGL-AISAVRLPREpNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12283    1 TVFVMQLSLKARERDLYEFFSKAgKVRDVRLIMD-RNSRRSKGVAYVEFYDVESVPLALALTGQRLLGQPIMV 72

RNA recognition motif (RRM) found in cyclophilin-33 (Cyp33) and similar proteins; This subfamily corresponds to the RRM of Cyp33, also termed peptidyl-prolyl cis-trans isomerase E (PPIase E), or cyclophilin E, or rotamase E. Cyp33 is a nuclear RNA-binding cyclophilin with an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal PPIase domain. Cyp33 possesses RNA-binding activity and preferentially binds to polyribonucleotide polyA and polyU, but hardly to polyG and polyC. It binds specifically to mRNA, which can stimulate its PPIase activity. Moreover, Cyp33 interacts with the third plant homeodomain (PHD3) zinc finger cassette of the mixed lineage leukemia (MLL) proto-oncoprotein and a poly-A RNA sequence through its RRM domain. It further mediates downregulation of the expression of MLL target genes HOXC8, HOXA9, CDKN1B, and C-MYC, in a proline isomerase-dependent manner. Cyp33 also possesses a PPIase activity that catalyzes cis-trans isomerization of the peptide bond preceding a proline, which has been implicated in the stimulation of folding and conformational changes in folded and unfolded proteins. The PPIase activity can be inhibited by the immunosuppressive drug cyclosporin A.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 528482848  99 FLGNLPYDVSEESIRDFFRGL-AISAVRLPREPNNpERLKGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDIA 171
Cdd:cd12347    2 YVGGLAEEVDEKVLHAAFIPFgDIVDIQIPLDYET-EKHRGFAFVEFEEAEDAAAAIdNMNESELFGRTIRVNLA 75

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein hnRNP D0, hnRNP A/B, hnRNP DL and similar proteins; This subfamily corresponds to the RRM2 of hnRNP D0, hnRNP A/B, hnRNP DL and similar proteins. hnRNP D0, a UUAG-specific nuclear RNA binding protein that may be involved in pre-mRNA splicing and telomere elongation. hnRNP A/B is an RNA unwinding protein with a high affinity for G- followed by U-rich regions. It has also been identified as an APOBEC1-binding protein that interacts with apolipoprotein B (apoB) mRNA transcripts around the editing site and thus plays an important role in apoB mRNA editing. hnRNP DL (or hnRNP D-like) is a dual functional protein that possesses DNA- and RNA-binding properties. It has been implicated in mRNA biogenesis at the transcriptional and post-transcriptional levels. All memembers in this family contain two putative RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a glycine- and tyrosine-rich C-terminus.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 528482848  99 FLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNPERlKGFGYAEFDDIESLLRALSLNEENLGNRRIRVDIA 171
Cdd:cd12329    3 FVGGLSPETTEEKIREYFGKFGnIVEIELPMDKKTNKR-RGFCFITFDSEEPVKKILETQFHVIGGKKVEVKKA 75

RNA recognition motif 2 (RRM2) found in yeast nucleolar protein 12 (Nop12p) and similar proteins; This subgroup corresponds to the RRM2 of Nop12p, which is encoded by YOL041C from Saccharomyces cerevisiae. It is a novel nucleolar protein required for pre-25S rRNA processing and normal rates of cell growth at low temperatures. Nop12p shares high sequence similarity with nucleolar protein 13 (Nop13p). Both, Nop12p and Nop13p, are not essential for growth. However, unlike Nop13p that localizes primarily to the nucleolus but is also present in the nucleoplasm to a lesser extent, Nop12p is localized to the nucleolus. Nop12p contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 528482848  99 FLGNLPYDVSEESIRDFFRGL-AISAVRLPREPNNpeRL-KGFGYAEFDDIESLLRALSLNE-ENLGNRRIRV 168
Cdd:cd12670    3 FVGNLAFEAEEEGLWRYFGKCgAIESVRIVRDPKT--NVgKGFAYVQFKDENAVEKALLLNEkPTMKGRKLRV 73

RNA recognition motif 2 (RRM2) found in splicing regulatory glutamine/lysine-rich protein 1 (SREK1) and similar proteins; This subfamily corresponds to the RRM2 of SREK1, also termed serine/arginine-rich-splicing regulatory protein 86-kDa (SRrp86), or splicing factor arginine/serine-rich 12 (SFRS12), or splicing regulatory protein 508 amino acid (SRrp508). SREK1 belongs to a family of proteins containing regions rich in serine-arginine dipeptides (SR proteins family), which is involved in bridge-complex formation and splicing by mediating protein-protein interactions across either introns or exons. It is a unique SR family member and it may play a crucial role in determining tissue specific patterns of alternative splicing. SREK1 can alter splice site selection by both positively and negatively modulating the activity of other SR proteins. For instance, SREK1 can activate SRp20 and repress SC35 in a dose-dependent manner both in vitro and in vivo. In addition, SREK1 contains two (some contain only one) RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and two serine-arginine (SR)-rich domains (SR domains) separated by an unusual glutamic acid-lysine (EK) rich region. The RRM and SR domains are highly conserved among other members of the SR superfamily. However, the EK domain is unique to SREK1. It plays a modulatory role controlling SR domain function by involvement in the inhibition of both constitutive and alternative splicing and in the selection of splice-site.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNPERlkgFGYAEFDDIESLLRALSLNEENLGNRRIRVDIADQS 174
Cdd:cd12260    6 TVYVGNLDPSTTADQLLEFFSQAGeVKYVRMAGDETQPTR---YAFVEFAEQTSVINALKLNGKMFGGRPLKVNHSNNA 81

RNA recognition motif 4 (RRM4) found in RNA-binding protein RBM12, RBM12B and similar proteins; This subfamily corresponds to the RRM4 of RBM12 and RBM12B. RBM12, also termed SH3/WW domain anchor protein in the nucleus (SWAN), is ubiquitously expressed. It contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two proline-rich regions, and several putative transmembrane domains. RBM12B show high sequence semilarity with RBM12. It contains five distinct RRMs as well. The biological roles of both RBM12 and RBM12B remain unclear.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 528482848  98 AFLGNLPYDVSEESIRDFFR--GLAISAVRLPREPNNpeRLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12514    2 IRITNLPYDATPVDIQRFFEdhGVRPEDVHLLRNKKG--RGNGEALVTFKSEGDAREVLKLNGKKLGKREAVV 72

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein (hnRNP) H protein family; This subfamily corresponds to the RRM2 of hnRNP H protein family which includes hnRNP H (also termed mcs94-1), hnRNP H2 (also termed FTP-3 or hnRNP H'), hnRNP F and hnRNP H3 (also termed hnRNP 2H9). They represent a group of nuclear RNA binding proteins that are involved in pre-mRNA processing, having similar RNA binding affinities and specifically recognizing the sequence GGGA. They can either stimulate or repress splicing upon binding to a GGG motif. hnRNP H binds to the RNA substrate in the presence or absence of these proteins, whereas hnRNP F binds to the nuclear mRNA only in the presence of cap-binding proteins. Furthermore, hnRNP H and hnRNP H2 are almost identical; both have been found to bind nuclear-matrix proteins. hnRNP H activates exon inclusion by binding G-rich intronic elements downstream of the 5' splice site in the transcripts of c-src, human immunodeficiency virus type 1 (HIV-1), Bcl-X, GRIN1, and myelin. It silences exons when bound to exonic elements in the transcripts of beta-tropomyosin, HIV-1, and alpha-tropomyosin. hnRNP H2 has been implicated in pre-mRNA 3' end formation. hnRNP H3 may be involved in the splicing arrest induced by heat shock. Most family members contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), except for hnRNP H3, in which the RRM1 is absent. RRM1 and RRM2 are responsible for the binding to the RNA at DGGGD motifs, and they play an important role in efficiently silencing the exon. Members in this family can regulate the alternative splicing of the fibroblast growth factor receptor 2 (FGFR2) transcripts, and function as silencers of FGFR2 exon IIIc through an interaction with the exonic GGG motifs. The lack of RRM1 could account for the reduced silencing activity within hnRNP H3. In addition, the family members have an extensive glycine-rich region near the C-terminus, which may allow them to homo- or heterodimerize. The family also includes a cytoplasmic poly(A)+ mRNA binding protein, GRSF-1, which interacts with RNA in a G-rich element-dependent manner. It may function in RNA packaging, stabilization of RNA secondary structure, or other macromolecular interactions. GRSF-1 also contains three potential RRMs responsible for the RNA binding, and two auxiliary domains (an acidic alpha-helical domain and an N-terminal alanine-rich region) that may play a role in protein-protein interactions and provide binding specificity.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 528482848 100 LGNLPYDVSEESIRDFFRGLAISAVRLPREPNNPERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12504    5 LRGLPYGCTKEEIAQFFSGLEIVPNGITLPMDRRGRSTGEAFVQFASQEIAEQALGKHKEKIGHRYIEI 73

RNA recognition motif 2 (RRM2) found in RNA-binding protein 12B (RBM12B) and similar proteins; This subgroup corresponds to the RRM2 of RBM12B which contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). Its biological role remains unclear.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  99 FLGNLPYDVSEESIRDFFRGLAISAVRLPREPNNpeRLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12746    6 FLRGMPYSATEDDVRNFFSGLKVDGVIFLKHPNG--RNNGNGLVKFATKEDASEGLKRHRQYMGSRFIEV 73

RNA recognition motif (RRM) found in cold inducible RNA binding protein (CIRBP), RNA binding motif protein 3 (RBM3) and similar proteins; This subfamily corresponds to the RRM domain of two structurally related heterogenous nuclear ribonucleoproteins, CIRBP (also termed CIRP or A18 hnRNP) and RBM3 (also termed RNPL), both of which belong to a highly conserved cold shock proteins family. The cold shock proteins can be induced after exposure to a moderate cold-shock and other cellular stresses such as UV radiation and hypoxia. CIRBP and RBM3 may function in posttranscriptional regulation of gene expression by binding to different transcripts, thus allowing the cell to response rapidly to environmental signals. However, the kinetics and degree of cold induction are different between CIRBP and RBM3. Tissue distribution of their expression is different. CIRBP and RBM3 may be differentially regulated under physiological and stress conditions and may play distinct roles in cold responses of cells. CIRBP, also termed glycine-rich RNA-binding protein CIRP, is localized in the nucleus and mediates the cold-induced suppression of cell cycle progression. CIRBP also binds DNA and possibly serves as a chaperone that assists in the folding/unfolding, assembly/disassembly and transport of various proteins. RBM3 may enhance global protein synthesis and the formation of active polysomes while reducing the levels of ribonucleoprotein complexes containing microRNAs. RBM3 may also serve to prevent the loss of muscle mass by its ability to decrease cell death. Furthermore, RBM3 may be essential for cell proliferation and mitosis. Both, CIRBP and RBM3, contain an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), that is involved in RNA binding, and C-terminal glycine-rich domain (RGG motif) that probably enhances RNA-binding via protein-protein and/or protein-RNA interactions. Like CIRBP, RBM3 can also bind to both RNA and DNA via its RRM domain.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 528482848  99 FLGNLPYDVSEESIRDFFRGLA-ISAVRLPREpNNPERLKGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDIADQS 174
Cdd:cd12449    4 FVGGLSFDTNEQSLEEVFSKYGqISEVVVVKD-RETQRSRGFGFVTFENPDDAKDAMmAMNGKSLDGRQIRVDQAGKS 80

RNA recognition motif 3 (RRM3) found in RNA-binding protein 12 (RBM12) and similar proteins; This subfamily corresponds to the RRM3 of RBM12. RBM12, also termed SH3/WW domain anchor protein in the nucleus (SWAN), is ubiquitously expressed. It contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two proline-rich regions, and several putative transmembrane domains. The biological role of RBM12 remains unclear.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  87 RSRLPRSPPYTAFLGNLPYDVSEESIRDFFRGLAI--SAVRLPREPNNpeRLKGFGYAEFDDIESLLRALSLNEENLGNR 164
Cdd:cd12512    1 RSRSPHEKGFCVYLKGLPYEAENKHVIEFFKKLDIveDSIYIAYGPNG--RATGEGFVEFRNEIDYKAALCRHKQYMGNR 78

                 ....
gi 528482848 165 RIRV 168
Cdd:cd12512   79 FIQV 82

RNA recognition motif 2 (RRM2) found in splicing factor 3B subunit 4 (SF3B4) and similar proteins; This subfamily corresponds to the RRM2 of SF3B4, also termed pre-mRNA-splicing factor SF3b 49 kDa (SF3b50), or spliceosome-associated protein 49 (SAP 49). SF3B4 is a component of the multiprotein complex splicing factor 3b (SF3B), an integral part of the U2 small nuclear ribonucleoprotein (snRNP) and the U11/U12 di-snRNP. SF3B is essential for the accurate excision of introns from pre-messenger RNA, and is involved in the recognition of the pre-mRNA's branch site within the major and minor spliceosomes. SF3B4 functions to tether U2 snRNP with pre-mRNA at the branch site during spliceosome assembly. It is an evolutionarily highly conserved protein with orthologs across diverse species. SF3B4 contains two closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). It binds directly to pre-mRNA and also interacts directly and highly specifically with another SF3B subunit called SAP 145.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 528482848  99 FLGNLPYDVSEESIRDFFR--GLAISAVRLPREPNNPERlKGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDIA 171
Cdd:cd12335    5 FIGNLDPEVDEKLLYDTFSafGVILQTPKIMRDPDTGNS-KGFGFVSFDSFEASDAAIeAMNGQYLCNRPITVSYA 79

RNA recognition motif 5 (RRM5) found in RNA-binding protein 19 (RBM19 or RBD-1) and similar proteins; This subfamily corresponds to the RRM5 of RBM19 and RRM4 of MRD1. RBM19, also termed RNA-binding domain-1 (RBD-1), is a nucleolar protein conserved in eukaryotes involved in ribosome biogenesis by processing rRNA and is essential for preimplantation development. It has a unique domain organization containing 6 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGL-AISAVRLPRE--PNNPERLKGFGYAEFDDIESLLRAL 154
Cdd:cd12318    2 TLFVKNLNFKTTEEALKKHFEKCgPIRSVTIAKKkdPKGPLLSMGYGFVEFKSPEAAQKAL 62

RNA recognition motif 2 (RRM2) found in nucleolin-like proteins mainly from plants; This subfamily corresponds to the RRM2 of a group of plant nucleolin-like proteins, including nucleolin 1 (also termed protein nucleolin like 1) and nucleolin 2 (also termed protein nucleolin like 2, or protein parallel like 1). They play roles in the regulation of ribosome synthesis and in the growth and development of plants. Like yeast nucleolin, nucleolin-like proteins possess two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGL-----AISAVRLPREPNNPErLKGFGYAEFDDIESLLRALSLNEENLGNRRIRVDIA 171
Cdd:cd12451    1 TIFVKGFDASLGEDTIRDELREHfgecgEVTNVRIPTDRETGE-LKGFAYIEFSTKEAKEKALELNGSDIAGGNLVVDEA 79

RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein RBM23, RBM39 and similar proteins; This subfamily corresponds to the RRM2 of RBM39 (also termed HCC1), a nuclear autoantigen that contains an N-terminal arginine/serine rich (RS) motif and three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). An octapeptide sequence called the RS-ERK motif is repeated six times in the RS region of RBM39. Although the cellular function of RBM23 remains unclear, it shows high sequence homology to RBM39 and contains two RRMs. It may possibly function as a pre-mRNA splicing factor.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 528482848  99 FLGNLPYDVSEESIRDFFRGL-AISAVRLPREPNNpERLKGFGYAEFDDIESLLRALS-LNEENLGNRRIRV 168
Cdd:cd12284    2 YVGSLHFNITEDMLRGIFEPFgKIEFVQLQKDPET-GRSKGYGFIQFRDAEDAKKALEqLNGFELAGRPMKV 72

RNA recognition motif 2 (RRM2) found in G-rich sequence factor 1 (GRSF-1) and similar proteins; This subfamily corresponds to the RRM2 of GRSF-1, a cytoplasmic poly(A)+ mRNA binding protein which interacts with RNA in a G-rich element-dependent manner. It may function in RNA packaging, stabilization of RNA secondary structure, or other macromolecular interactions. GRSF-1 contains three potential RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which are responsible for the RNA binding. In addition, GRSF-1 has two auxiliary domains, an acidic alpha-helical domain and an N-terminal alanine-rich region, that may play a role in protein-protein interactions and provide binding specificity.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 528482848 100 LGNLPYDVSEESIRDFFRGLAISAVRLPREPNNpERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12505    6 LRGLPYSCTEADIAHFFSGLDIVDITFVMDLRG-GRKTGEAFVQFASPEMAAQALLKHKEEIGNRYIEI 73

RNA recognition motif 1 (RRM1) found in yeast protein gar2 and similar proteins; This subfamily corresponds to the RRM1 of yeast protein gar2, a novel nucleolar protein required for 18S rRNA and 40S ribosomal subunit accumulation. It shares similar domain architecture with nucleolin from vertebrates and NSR1 from Saccharomyces cerevisiae. The highly phosphorylated N-terminal domain of gar2 is made up of highly acidic regions separated from each other by basic sequences, and contains multiple phosphorylation sites. The central domain of gar2 contains two closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The C-terminal RGG (or GAR) domain of gar2 is rich in glycine, arginine and phenylalanine residues.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 528482848  97 TAFLGNLPYDVSEESIRDFFR--GLAISAvRLPREpNNPERLKGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDIA 171
Cdd:cd12447    1 TLFVGGLSWNVDDPWLKKEFEkyGGVISA-RVITD-RGSGRSKGYGYVDFATPEAAQKALaAMSGKEIDGRQINVDFS 76

RNA recognition motif 3 (RRM3) found in SMART/HDAC1-associated repressor protein (SHARP) and similar proteins; This subfamily corresponds to the RRM3 of SHARP, also termed Msx2-interacting protein (MINT), or SPEN homolog, an estrogen-inducible transcriptional repressor that interacts directly with the nuclear receptor corepressor SMRT, histone deacetylases (HDACs) and components of the NuRD complex. SHARP recruits HDAC activity and binds to the steroid receptor RNA coactivator SRA through four conserved N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), further suppressing SRA-potentiated steroid receptor transcription activity. Thus, SHARP has the capacity to modulate both liganded and nonliganded nuclear receptors. SHARP also has been identified as a component of transcriptional repression complexes in Notch/RBP-Jkappa signaling pathways. In addition to the N-terminal RRMs, SHARP possesses a C-terminal SPOC domain (Spen paralog and ortholog C-terminal domain), which is highly conserved among Spen proteins.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 528482848  97 TAFLGNLPYDVSEESIRDFFRGLA-ISAVRLPREPNNPErlkgFGYAEFDDIESLLRAL-SLNEENLGNRRIRV 168
Cdd:cd12350    4 TLFIGNLEKTTTYGDLRNIFERFGeIIDIDIKKQNGNPQ----YAFLQYCDIASVVKAIkKMDGEYLGNNRLKL 73

RNA recognition motif 2 (RRM2) found in RNA-binding protein 12 (RBM12) and similar proteins; This subgroup corresponds to the RRM2 of RBM12, also termed SH3/WW domain anchor protein in the nucleus (SWAN), which is ubiquitously expressed. It contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two proline-rich regions, and several putative transmembrane domains. The biological role of RBM12 remains unclear.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 528482848  95 PYTAFLGnLPYDVSEESIRDFFRGLAISAVRLPREP---NNPERLKGFgYAEFDDIESLLRalslNEENLGNRRIRVDIA 171
Cdd:cd12747    2 LYVHLHG-MPFSATEADVRDFFHGLRIDAIHMLKDHlgrNNGNALVKF-YSPQDTFEALKR----NRMMMGQRYIEVSPA 75

RNA recognition motif 1 (RRM1) found in TAR DNA-binding protein 43 (TDP-43) and similar proteins; This subfamily corresponds to the RRM1 of TDP-43 (also termed TARDBP), a ubiquitously expressed pathogenic protein whose normal function and abnormal aggregation are directly linked to the genetic disease cystic fibrosis, and two neurodegenerative disorders: frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). TDP-43 binds both DNA and RNA, and has been implicated in transcriptional repression, pre-mRNA splicing and translational regulation. TDP-43 is a dimeric protein with two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal glycine-rich domain. The RRMs are responsible for DNA and RNA binding; they bind to TAR DNA and RNA sequences with UG-repeats. The glycine-rich domain can interact with the hnRNP family proteins to form the hnRNP-rich complex involved in splicing inhibition. It is also essential for the cystic fibrosis transmembrane conductance regulator (CFTR) exon 9-skipping activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 528482848 102 NLPYDVSEESIRDFFRGLA-ISAVRLPREPNNpERLKGFGYAEFDDIESLLRALSlNEENLGNRRIRVDIA 171
Cdd:cd12321    6 GLPWKTTEQDLKEYFSTFGeVLMVQVKKDPKT-GRSKGFGFVRFASYETQVKVLS-QRHMIDGRWCDVKLP 74

RNA recognition motif 1 (RRM1) found in U2 large nuclear ribonucleoprotein auxiliary factor U2AF 65 kDa subunit (U2AF65) and similar proteins; The subfamily corresponds to the RRM1 of U2AF65 and dU2AF50. U2AF65, also termed U2AF2, is the large subunit of U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF), which has been implicated in the recruitment of U2 snRNP to pre-mRNAs and is a highly conserved heterodimer composed of large and small subunits. U2AF65 specifically recognizes the intron polypyrimidine tract upstream of the 3' splice site and promotes binding of U2 snRNP to the pre-mRNA branchpoint. U2AF65 also plays an important role in the nuclear export of mRNA. It facilitates the formation of a messenger ribonucleoprotein export complex, containing both the NXF1 receptor and the RNA substrate. Moreover, U2AF65 interacts directly and specifically with expanded CAG RNA, and serves as an adaptor to link expanded CAG RNA to NXF1 for RNA export. U2AF65 contains an N-terminal RS domain rich in arginine and serine, followed by a proline-rich segment and three C-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The N-terminal RS domain stabilizes the interaction of U2 snRNP with the branch point (BP) by contacting the branch region, and further promotes base pair interactions between U2 snRNA and the BP. The proline-rich segment mediates protein-protein interactions with the RRM domain of the small U2AF subunit (U2AF35 or U2AF1). The RRM1 and RRM2 are sufficient for specific RNA binding, while RRM3 is responsible for protein-protein interactions. The family also includes Splicing factor U2AF 50 kDa subunit (dU2AF50), the Drosophila ortholog of U2AF65. dU2AF50 functions as an essential pre-mRNA splicing factor in flies. It associates with intronless mRNAs and plays a significant and unexpected role in the nuclear export of a large number of intronless mRNAs.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 528482848  99 FLGNLPYDVSEESIRDFFRGlAISAVRLPREPNNP------ERLKGFGYAEFDDIESLLRALSLNEENLGNRRIRV 168
Cdd:cd12230    5 YVGNIPPGITEEELMDFFNQ-AMRAAGLTQAPGNPvlavqiNPDKNFAFVEFRSVEETTAALALDGIIFKGQPLKI 79

RNA recognition motif 5 (RRM5) found in yeast multiple RNA-binding domain-containing protein 1 (MRD1) and similar proteins; This subgroup corresponds to the RRM5 of MRD1 which is encoded by a novel yeast gene MRD1 (multiple RNA-binding domain). It is well-conserved in yeast and its homologs exist in all eukaryotes. MRD1 is present in the nucleolus and the nucleoplasm. It interacts with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs (snoRNAs). MRD1 is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. It contains 5 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which may play an important structural role in organizing specific rRNA processing events.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 528482848 102 NLPYDVSEESIRDFFRGLA-ISAVRLPREPNNPERlkGFGYAEFDDIESLLRAL-SLNEENLGNRRIRVDIA 171
Cdd:cd12570    7 NLPFEATKKDVRTLFSSYGqLKSVRVPKKFDQSAR--GFAFVEFSTAKEALNAMnALKDTHLLGRRLVLQYA 76