polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234    18 EELRRLFTNYGSVVECDVM------NRC-AFVHLENTDMAEAAIAALNGTIFKGQPIVV-------------EAGRPKYG 77
Cdd:TIGR01628 300 EKLRELFSECGEITSAKVMldekgvSRGfGFVCFSNPEEANRAVTEMHGRMLGGKPLYValaqrkeqrrahlQDQFMQLQ 379

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234    78 PGG--GSRGQPGSGDNpGRRPSQVQGGGADKRPHESNTNFKRNFreevggrFSNEGPRSSNSSA--AKFGPVRNESNYRQ 153
Cdd:TIGR01628 380 PRMrqLPMGSPMGGAM-GQPPYYGQGPQQQFNGQPLGWPRMSMM-------PTPMGPGGPLRPNglAPMNAVRAPSRNAQ 451

                         170       180
                  ....*....|....*....|
gi 24651234   154 QRSAPYSKGPPNNESSNQGQ 173
Cdd:TIGR01628 452 NAAQKPPMQPVMYPPNYQSL 471

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVM-----NRC---AFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRPK 75
Cdd:COG0724   3 KIYVGNLPySVTEEDLRELFSEYGEVTSVKLItdretGRSrgfGFVEMPDDEEAQAAIEALNGAELMGRTLKVNEARPR 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234     7 VFVGSLPR-CKPEELRRLFTNYGSVVECDVMNR-------CAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:pfam00076   1 LFVGNLPPdTTEEDLKDLFSKFGPIKSIRLVRDetgrskgFAFVEFEDEEDAEKAIEALNGKELGGREL 69

transcription termination factor Rho; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234   70 EAGRPKYGPGGGSRGQPGSGDNPGRRPSQVQGGGADKRPHESNTNFKRNFREEVGGRfSNEGPRSSNSSAAKFGPVRNES 149
Cdd:PRK12678 127 ARERRERGEAARRGAARKAGEGGEQPATEARADAAERTEEEERDERRRRGDREDRQA-EAERGERGRREERGRDGDDRDR 205

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234  150 NYRQQRSAPYSkgppNNESSNQGQGFRNKFAGGGKFGGSAGNEGRFGSNRFQQRDNSGPQPGRRNFKNSPTSGYRGGGNN 229
Cdd:PRK12678 206 RDRREQGDRRE----ERGRRDGGDRRGRRRRRDRRDARGDDNREDRGDRDGDDGEGRGGRRGRRFRDRDRRGRRGGDGGN 281

                 ..
gi 24651234  230 SD 231
Cdd:PRK12678 282 ER 283

RNA recognition motif 1 (RRM1) found in vertebrate RRM-containing coactivator activator/modulator (CoAA); This subgroup corresponds to the RRM1 of CoAA, also termed RNA-binding protein 14 (RBM14), or paraspeckle protein 2 (PSP2), or synaptotagmin-interacting protein (SYT-interacting protein), a heterogeneous nuclear ribonucleoprotein (hnRNP)-like protein identified as a nuclear receptor coactivator. It mediates transcriptional coactivation and RNA splicing effects in a promoter-preferential manner and is enhanced by thyroid hormone receptor-binding protein (TRBP). CoAA contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a TRBP-interacting domain. It stimulates transcription through its interactions with coactivators, such as TRBP and CREB-binding protein CBP/p300, via the TRBP-interacting domain and interaction with an RNA-containing complex, such as DNA-dependent protein kinase-poly(ADP-ribose) polymerase complexes, via the RRMs.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12608   2 KIFVGNVDeDTSQEELSALFEPYGAVLSCAVMKQFAFVHMRGEAAADRAIRELNGRELHGRALVVE 67

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVM-----NRC---AFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRPK 75
Cdd:COG0724   3 KIYVGNLPySVTEEDLRELFSEYGEVTSVKLItdretGRSrgfGFVEMPDDEEAQAAIEALNGAELMGRTLKVNEARPR 81

RNA recognition motif (RRM) superfamily; RRM, also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), is a highly abundant domain in eukaryotes found in proteins involved in post-transcriptional gene expression processes including mRNA and rRNA processing, RNA export, and RNA stability. This domain is 90 amino acids in length and consists of a four-stranded beta-sheet packed against two alpha-helices. RRM usually interacts with ssRNA, but is also known to interact with ssDNA as well as proteins. RRM binds a variable number of nucleotides, ranging from two to eight. The active site includes three aromatic side-chains located within the conserved RNP1 and RNP2 motifs of the domain. The RRM domain is found in a variety heterogeneous nuclear ribonucleoproteins (hnRNPs), proteins implicated in regulation of alternative splicing, and protein components of small nuclear ribonucleoproteins (snRNPs).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 24651234   7 VFVGSLPR-CKPEELRRLFTNYGSVVECDVMN-------RCAFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd00590   1 LFVGNLPPdTTEEDLRELFSKFGEVVSVRIVRdrdgkskGFAFVEFESPEDAEKALEALNGTELGGRPLKVS 72

RNA recognition motif 2 (RRM2) found in yeast meiotic activator RIM4 and similar proteins; This subfamily corresponds to the RRM2 of RIM4, also termed regulator of IME2 protein 4, a putative RNA binding protein that is expressed at elevated levels early in meiosis. It functions as a meiotic activator required for both the IME1- and IME2-dependent pathways of meiotic gene expression, as well as early events of meiosis, such as meiotic division and recombination, in Saccharomyces cerevisiae. RIM4 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The family also includes a putative RNA-binding protein termed multicopy suppressor of sporulation protein Msa1. It is a putative RNA-binding protein encoded by a novel gene, msa1, from the fission yeast Schizosaccharomyces pombe. Msa1 may be involved in the inhibition of sexual differentiation by controlling the expression of Ste11-regulated genes, possibly through the pheromone-signaling pathway. Like RIM4, Msa1 also contains two RRMs, both of which are essential for the function of Msa1.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 24651234   7 VFVGSL-PRCKPEELRRLFTNYGSVVECDVMNRC------AFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12454   6 IFVGQLdPKTTDSELFRRFSKYGKIVDCKLIKRPepvnafAFLRFESEEAAEAAVEEENHSEFLNKQIRVQ 76

RNA recognition motif 1 (RRM1) and 2 (RRM2) found in CELF/Bruno-like family of RNA binding proteins and plant flowering time control protein FCA; This subfamily corresponds to the RRM1 and RRM2 domains of the CUGBP1 and ETR-3-like factors (CELF) as well as plant flowering time control protein FCA. CELF, also termed BRUNOL (Bruno-like) proteins, is a family of structurally related RNA-binding proteins involved in regulation of pre-mRNA splicing in the nucleus, and control of mRNA translation and deadenylation in the cytoplasm. The family contains six members: CELF-1 (also known as BRUNOL-2, CUG-BP1, NAPOR, EDEN-BP), CELF-2 (also known as BRUNOL-3, ETR-3, CUG-BP2, NAPOR-2), CELF-3 (also known as BRUNOL-1, TNRC4, ETR-1, CAGH4, ER DA4), CELF-4 (BRUNOL-4), CELF-5 (BRUNOL-5) and CELF-6 (BRUNOL-6). They all contain three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The low sequence conservation of the linker region is highly suggestive of a large variety in the co-factors that associate with the various CELF family members. Based on both, sequence similarity and function, the CELF family can be divided into two subfamilies, the first containing CELFs 1 and 2, and the second containing CELFs 3, 4, 5, and 6. The different CELF proteins may act through different sites on at least some substrates. Furthermore, CELF proteins may interact with each other in varying combinations to influence alternative splicing in different contexts. This subfamily also includes plant flowering time control protein FCA that functions in the posttranscriptional regulation of transcripts involved in the flowering process. FCA contains two RRMs, and a WW protein interaction domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   6 KVFVGSLPR-CKPEELRRLFTNYGSVVECDVM--------NRCAFVHLENTDMAEAAIAALNGT-IFKG--QPIVV 69
Cdd:cd12361   1 KLFVGMIPKtASEEDVRPLFEQFGNIEEVQILrdkqtgqsKGCAFVTFSTREEALRAIEALHNKkTMPGcsSPLQV 76

RNA recognition motif 2 (RRM2) found in plant flowering time control protein FCA and similar proteins; This subgroup corresponds to the RRM2 of FCA, a gene controlling flowering time in Arabidopsis, which encodes a flowering time control protein that functions in the posttranscriptional regulation of transcripts involved in the flowering process. The flowering time control protein FCA contains two RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNP (ribonucleoprotein domains), and a WW protein interaction domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   6 KVFVGSLPR-CKPEELRRLFTNYGSVVECDVM--------NRCAFVHLENTDMAEAAIAALNGTI-FKG--QPIVV 69
Cdd:cd12637   1 KLFVGSLPKtATEQEVRDLFEAYGEVEEVYLMkdpvtqqgTGCAFVKFAYKEEALAAIRSLNGTVtFDGcsRPVEV 76

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein C (hnRNP C)-related proteins; This subfamily corresponds to the RRM in the hnRNP C-related protein family, including hnRNP C proteins, Raly, and Raly-like protein (RALYL). hnRNP C proteins, C1 and C2, are produced by a single coding sequence. They are the major constituents of the heterogeneous nuclear RNA (hnRNA) ribonucleoprotein (hnRNP) complex in vertebrates. They bind hnRNA tightly, suggesting a central role in the formation of the ubiquitous hnRNP complex; they are involved in the packaging of the hnRNA in the nucleus and in processing of pre-mRNA such as splicing and 3'-end formation. Raly, also termed autoantigen p542, is an RNA-binding protein that may play a critical role in embryonic development. The biological role of RALYL remains unclear. It shows high sequence homology with hnRNP C proteins and Raly. Members of this family are characterized by an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal auxiliary domain. The Raly proteins contain a glycine/serine-rich stretch within the C-terminal regions, which is absent in the hnRNP C proteins. Thus, the Raly proteins represent a newly identified class of evolutionarily conserved autoepitopes.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24651234   5 AKVFVGSLP--RCKPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:cd12341   1 SRIFVGNLPtdQMTKEDLEEIFSKYGKILGISLHKGYGFVQFDNEEDARAAVAGENGRTIKGQRL 65

RNA recognition motif 3 (RRM3) found in heterogeneous nuclear ribonucleoprotein R (hnRNP R) and similar proteins; This subfamily corresponds to the RRM3 in hnRNP R, hnRNP Q, and APOBEC-1 complementation factor (ACF). hnRNP R is a ubiquitously expressed nuclear RNA-binding protein that specifically bind mRNAs with a preference for poly(U) stretches and has been implicated in mRNA processing and mRNA transport, and also acts as a regulator to modify binding to ribosomes and RNA translation. hnRNP Q is also a ubiquitously expressed nuclear RNA-binding protein. It has been identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome, and has been implicated in the regulation of specific mRNA transport. ACF is an RNA-binding subunit of a core complex that interacts with apoB mRNA to facilitate C to U RNA editing. It may also act as an apoB mRNA recognition factor and chaperone and play a key role in cell growth and differentiation. This family also includes two functionally unknown RNA-binding proteins, RBM46 and RBM47. All members contain three conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234   7 VFVGSLPRCKPEE-LRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRP 74
Cdd:cd12251   4 LYVRNLMLSTTEEkLRELFSEYGKVERVKKIKDYAFVHFEERDDAVKAMEEMNGKELEGSEIEVSLAKP 72

RNA recognition motif 1 (RRM1) found in the p54nrb/PSF/PSP1 family; This subfamily corresponds to the RRM1 of the p54nrb/PSF/PSP1 family, including 54 kDa nuclear RNA- and DNA-binding protein (p54nrb or NonO or NMT55), polypyrimidine tract-binding protein (PTB)-associated-splicing factor (PSF or POMp100), paraspeckle protein 1 (PSP1 or PSPC1), which are ubiquitously expressed and are conserved in vertebrates. p54nrb is a multi-functional protein involved in numerous nuclear processes including transcriptional regulation, splicing, DNA unwinding, nuclear retention of hyperedited double-stranded RNA, viral RNA processing, control of cell proliferation, and circadian rhythm maintenance. PSF is also a multi-functional protein that binds RNA, single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) and many factors, and mediates diverse activities in the cell. PSP1 is a novel nucleolar factor that accumulates within a new nucleoplasmic compartment, termed paraspeckles, and diffusely distributes in the nucleoplasm. The cellular function of PSP1 remains unknown currently. This subfamily also includes some p54nrb/PSF/PSP1 homologs from invertebrate species, such as the Drosophila melanogaster gene no-ontransient A (nonA) encoding puff-specific protein Bj6 (also termed NONA) and Chironomus tentans hrp65 gene encoding protein Hrp65. D. melanogaster NONA is involved in eye development and behavior, and may play a role in circadian rhythm maintenance, similar to vertebrate p54nrb. C. tentans Hrp65 is a component of nuclear fibers associated with ribonucleoprotein particles in transit from the gene to the nuclear pore. All family members contain a DBHS domain (for Drosophila behavior, human splicing), which comprises two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a charged protein-protein interaction module. PSF has an additional large N-terminal domain that differentiates it from other family members.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 24651234   6 KVFVGSLPRC-KPEELRRLFTNYGSVVECdVMNR---CAFVHLENTDMAEAAIAALNGTIFKGQPIVV 69
Cdd:cd12332   3 RLFVGNLPNDiTEEEFKELFQKYGEVSEV-FLNKgkgFGFIRLDTRANAEAAKAELDGTPRKGRQLRV 69

RNA recognition motif 2 (RRM2) found in Drosophila sex-lethal (SXL) and similar proteins; This subfamily corresponds to the RRM2 of the sex-lethal protein (SXL) which governs sexual differentiation and X chromosome dosage compensation in Drosophila melanogaster. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds also to its own pre-mRNA and promotes female-specific alternative splicing. SXL contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   5 AKVFVGSLPRCKPE-ELRRLFTNYGSVVECDVMNR--------CAFVHLENTDMAEAAIAALNGTIFKG--QPIVV 69
Cdd:cd12651   3 TNLYVTNLPRTITEdELDTIFGAYGNIVQKNLLRDkltgrprgVAFVRYDKREEAQAAISALNGTIPEGgtQPLSV 78

RNA recognition motif 1 (RRM1) found in serine/arginine-rich splicing factor 4 (SRSF4) and similar proteins; This subfamily corresponds to the RRM1 in three serine/arginine (SR) proteins: serine/arginine-rich splicing factor 4 (SRSF4 or SRp75 or SFRS4), serine/arginine-rich splicing factor 5 (SRSF5 or SRp40 or SFRS5 or HRS), serine/arginine-rich splicing factor 6 (SRSF6 or SRp55). SRSF4 plays an important role in both, constitutive and alternative, splicing of many pre-mRNAs. It can shuttle between the nucleus and cytoplasm. SRSF5 regulates both alternative splicing and basal splicing. It is the only SR protein efficiently selected from nuclear extracts (NE) by the splicing enhancer (ESE) and essential for enhancer activation. SRSF6 preferentially interacts with a number of purine-rich splicing enhancers (ESEs) to activate splicing of the ESE-containing exon. It is the only protein from HeLa nuclear extract or purified SR proteins that specifically binds B element RNA after UV irradiation. SRSF6 may also recognize different types of RNA sites. Members in this family contain two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a C-terminal RS domains rich in serine-arginine dipeptides.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRP 74
Cdd:cd12337   1 RVYIGRLPyRARERDVERFFRGYGRIRDINLKNGFGFVEFEDPRDADDAVYELNGKELCGERVIVEHARG 70

RNA recognition motif 2 (RRM2) found in the Spen (split end) protein family; This subfamily corresponds to the RRM2 domain in the Spen (split end) protein 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 possess 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 termed 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.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 24651234   4 TAKVFVGSL-PRCKPEELRRLFTNYGSVVECDVM-------NRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGR 73
Cdd:cd12309   2 TRTLFVGNLeITITEEELRRAFERYGVVEDVDIKrpprgqgNAYAFVKFLNLDMAHRAKVAMSGQYIGRNQIKIGYGK 79

RNA recognition motif (RRM) found in the scaffold attachment factor (SAFB) family; This subfamily corresponds to the RRM domain of the SAFB family, including scaffold attachment factor B1 (SAFB1), scaffold attachment factor B2 (SAFB2), SAFB-like transcriptional modulator (SLTM), and similar proteins, which are ubiquitously expressed. SAFB1, SAFB2 and SLTM have been implicated in many diverse cellular processes including cell growth and transformation, stress response, and apoptosis. They share high sequence similarities and all contain a scaffold attachment factor-box (SAF-box, also known as SAP domain) DNA-binding motif, an RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a region rich in glutamine and arginine residues. SAFB1 is a nuclear protein with a distribution similar to that of SLTM, but unlike that of SAFB2, which is also found in the cytoplasm. To a large extent, SAFB1 and SLTM might share similar functions, such as the inhibition of an oestrogen reporter gene. The additional cytoplasmic localization of SAFB2 implies that it could play additional roles in the cytoplasmic compartment which are distinct from the nuclear functions shared with SAFB1 and SLTM.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234   6 KVFVGSL-PRCKPEELRRLFTNYGSVVECDVMNR--------CAFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12417   1 NLWISGLsDTTKAADLKKIFSKYGKVVSAKVVTSartpgsrcYGYVTMASVEEADLCIKSLNKTELHGRVITVE 74

RNA recognition motif 1 (RRM1) found in vertebrate serine/arginine-rich splicing factor 6 (SRSF6); This subfamily corresponds to the RRM1 of SRSF6, also termed pre-mRNA-splicing factor SRp55, which is an essential splicing regulatory serine/arginine (SR) protein that preferentially interacts with a number of purine-rich splicing enhancers (ESEs) to activate splicing of the ESE-containing exon. It is the only protein from HeLa nuclear extract or purified SR proteins that specifically binds B element RNA after UV irradiation. SRSF6 may also recognize different types of RNA sites. For instance, it does not bind to the purine-rich sequence in the calcitonin-specific ESE, but binds to a region adjacent to the purine tract. Moreover, cellular levels of SRSF6 may control tissue-specific alternative splicing of the calcitonin/ calcitonin gene-related peptide (CGRP) pre-mRNA. SRSF6 contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a C-terminal SR domains rich in serine-arginine dipeptides.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGR 73
Cdd:cd12596   3 RVYIGRLSyHVREKDIQRFFSGYGKLLEVDLKNGYGFVEFEDSRDADDAVYELNGKELCGERVIVEHAR 71

RNA recognition motif 1 (RRM1) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM1 of RBM28 and Nop4p. RBM28 is a specific nucleolar component of the spliceosomal small nuclear ribonucleoproteins (snRNPs), possibly coordinating their transition through the nucleolus. It specifically associates with U1, U2, U4, U5, and U6 small nuclear RNAs (snRNAs), and may play a role in the maturation of both small nuclear and ribosomal RNAs. RBM28 has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an extremely acidic region between RRM2 and RRM3. The family also includes nucleolar protein 4 (Nop4p or Nop77p) encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p also contains four RRMs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVM-----NRC---AFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRPK 75
Cdd:cd12413   1 TLFVRNLPyDTTDEQLEELFSDVGPVKRCFVVkdkgkDKCrgfGYVTFALAEDAQRALEEVKGKKFGGRKIKVELAKKK 79

RNA recognition motif (RRM) found in vertebrate RNA-binding protein Raly; This subgroup corresponds to the RRM of Raly, also termed autoantigen p542, or heterogeneous nuclear ribonucleoprotein C-like 2, or hnRNP core protein C-like 2, or hnRNP associated with lethal yellow protein homolog, an RNA-binding protein that may play a critical role in embryonic development. It is encoded by Raly, a ubiquitously expressed gene of unknown function. Raly shows a high degree of identity with the 5' sequences of p542 gene encoding autoantigen, which can cross-react with EBNA-1 of the Epstein Barr virus. Raly contains two distinct domains, an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal auxiliary domain that includes a unique glycine/serine-rich stretch.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234   5 AKVFVGSLPRC--KPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVE-AGRPK 75
Cdd:cd12604   2 SRVFIGNLNTAvvKKSDVETIFSKYGRVVGCSVHKGYAFVQYTNERHARAAVIGENGRVLAGQTLDINmAGEPK 75

RNA recognition motif 3 (RRM3) found found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM3 of type I poly(A)-binding proteins (PABPs), highly conserved proteins that bind to the poly(A) tail present at the 3' ends of most eukaryotic mRNAs. They have been implicated in the regulation of poly(A) tail length during the polyadenylation reaction, translation initiation, mRNA stabilization by influencing the rate of deadenylation and inhibition of mRNA decapping. The family represents type I polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 1 (PABP-1 or PABPC1), polyadenylate-binding protein 3 (PABP-3 or PABPC3), polyadenylate-binding protein 4 (PABP-4 or APP-1 or iPABP), polyadenylate-binding protein 5 (PABP-5 or PABPC5), polyadenylate-binding protein 1-like (PABP-1-like or PABPC1L), polyadenylate-binding protein 1-like 2 (PABPC1L2 or RBM32), polyadenylate-binding protein 4-like (PABP-4-like or PABPC4L), yeast polyadenylate-binding protein, cytoplasmic and nuclear (PABP or ACBP-67), and similar proteins. PABP-1 is an ubiquitously expressed multifunctional protein that may play a role in 3' end formation of mRNA, translation initiation, mRNA stabilization, protection of poly(A) from nuclease activity, mRNA deadenylation, inhibition of mRNA decapping, and mRNP maturation. Although PABP-1 is thought to be a cytoplasmic protein, it is also found in the nucleus. PABP-1 may be involved in nucleocytoplasmic trafficking and utilization of mRNP particles. PABP-1 contains four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), a less well conserved linker region, and a proline-rich C-terminal conserved domain (CTD). PABP-3 is a testis-specific poly(A)-binding protein specifically expressed in round spermatids. It is mainly found in mammalian and may play an important role in the testis-specific regulation of mRNA homeostasis. PABP-3 shows significant sequence similarity to PABP-1. However, it binds to poly(A) with a lower affinity than PABP-1. PABP-1 possesses an A-rich sequence in its 5'-UTR and allows binding of PABP and blockage of translation of its own mRNA. In contrast, PABP-3 lacks the A-rich sequence in its 5'-UTR. PABP-4 is an inducible poly(A)-binding protein (iPABP) that is primarily localized to the cytoplasm. It shows significant sequence similarity to PABP-1 as well. The RNA binding properties of PABP-1 and PABP-4 appear to be identical. PABP-5 is encoded by PABPC5 gene within the X-specific subinterval, and expressed in fetal brain and in a range of adult tissues in mammalian, such as ovary and testis. It may play an important role in germ cell development. Moreover, unlike other PABPs, PABP-5 contains only four RRMs, but lacks both the linker region and the CTD. PABP-1-like and PABP-1-like 2 are the orthologs of PABP-1. PABP-4-like is the ortholog of PABP-5. Their cellular functions remain unclear. The family also includes the yeast PABP, a conserved poly(A) binding protein containing poly(A) tails that can be attached to the 3'-ends of mRNAs. The yeast PABP and its homologs may play important roles in the initiation of translation and in mRNA decay. Like vertebrate PABP-1, the yeast PABP contains four RRMs, a linker region, and a proline-rich CTD as well. The first two RRMs are mainly responsible for specific binding to poly(A). The proline-rich region may be involved in protein-protein interactions.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234  17 PEELRRLFTNYGSVVECDVM------NRC-AFVHLENTDMAEAAIAALNGTIFKGQPIVVeaGR 73
Cdd:cd12380  15 DDELKELFEKYGKITSAKVMkddsgkSKGfGFVNFENHEAAQKAVEELNGKELNGKKLYV--GR 76

RNA recognition motif 2 (RRM2) found in yeast nucleolar protein 4 (Nop4p) and similar proteins; This subgroup corresponds to the RRM2 of Nop4p (also known as Nop77p), encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 24651234  16 KPEELRRLFTNYGSVVECDV-------MNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12675  14 KPVHLKKLFGRYGKVVEATIprkkggkLSGFAFVTMKGRKNAEEALESVNGLEIDGRPVAVD 75

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein G (hnRNP G), Y chromosome RNA recognition motif 1 (hRBMY), testis-specific heterogeneous nuclear ribonucleoprotein G-T (hnRNP G-T) and similar proteins; This subfamily corresponds to the RRM domain of hnRNP G, also termed glycoprotein p43 or RBMX, an RNA-binding motif protein located on the X chromosome. It is expressed ubiquitously and has been implicated in the splicing control of several pre-mRNAs. Moreover, hnRNP G may function as a regulator of transcription for SREBP-1c and GnRH1. Research has shown that hnRNP G may also act as a tumor-suppressor since it upregulates the Txnip gene and promotes the fidelity of DNA end-joining activity. In addition, hnRNP G appears to play a critical role in proper neural development of zebrafish and frog embryos. The family also includes several paralogs of hnRNP G, such as hRBMY and hnRNP G-T (also termed RNA-binding motif protein, X-linked-like-2). Both, hRBMY and hnRNP G-T, are exclusively expressed in testis and critical for male fertility. Like hnRNP G, hRBMY and hnRNP G-T interact with factors implicated in the regulation of pre-mRNA splicing, such as hTra2-beta1 and T-STAR. Although members in this family share a high conserved N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), they appear to recognize different RNA targets. For instance, hRBMY interacts specifically with a stem-loop structure in which the loop is formed by the sequence CA/UCAA. In contrast, hnRNP G associates with single stranded RNA sequences containing a CCA/C motif. In addition to the RRM, hnRNP G contains a nascent transcripts targeting domain (NTD) in the middle region and a novel auxiliary RNA-binding domain (RBD) in its C-terminal region. The C-terminal RBD exhibits distinct RNA binding specificity, and would play a critical role in the regulation of alternative splicing by hnRNP G.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234   6 KVFVGSLPRCKPEE-LRRLFTNYGSVVECDVM-----NRC---AFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12382   3 KLFIGGLNTETNEKaLEAVFGKYGRIVEVLLMkdretNKSrgfAFVTFESPADAKDAARDMNGKELDGKAIKVE 76

polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234    18 EELRRLFTNYGSVVECDVM------NRC-AFVHLENTDMAEAAIAALNGTIFKGQPIVV-------------EAGRPKYG 77
Cdd:TIGR01628 300 EKLRELFSECGEITSAKVMldekgvSRGfGFVCFSNPEEANRAVTEMHGRMLGGKPLYValaqrkeqrrahlQDQFMQLQ 379

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234    78 PGG--GSRGQPGSGDNpGRRPSQVQGGGADKRPHESNTNFKRNFreevggrFSNEGPRSSNSSA--AKFGPVRNESNYRQ 153
Cdd:TIGR01628 380 PRMrqLPMGSPMGGAM-GQPPYYGQGPQQQFNGQPLGWPRMSMM-------PTPMGPGGPLRPNglAPMNAVRAPSRNAQ 451

                         170       180
                  ....*....|....*....|
gi 24651234   154 QRSAPYSKGPPNNESSNQGQ 173
Cdd:TIGR01628 452 NAAQKPPMQPVMYPPNYQSL 471

RNA recognition motif (RRM) found in U2-associated protein SR140 and similar proteins; This subgroup corresponds to the RRM of SR140 (also termed U2 snRNP-associated SURP motif-containing protein orU2SURP, or 140 kDa Ser/Arg-rich domain protein) which is a putative splicing factor mainly found in higher eukaryotes. Although it is initially identified as one of the 17S U2 snRNP-associated proteins, the molecular and physiological function of SR140 remains unclear. SR140 contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a SWAP/SURP domain that is found in a number of pre-mRNA splicing factors in the middle region, and a C-terminal arginine/serine-rich domain (RS domain).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 24651234   4 TAKVFVGSL-PRCKPEELRRLFTNYGSVVECDVM-----------NRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEA 71
Cdd:cd12223   1 TTNLYVGNLpPSVTEEVLLREFGRFGPLASVKIMwprteeerrrnRNCGFVAFMSRADAERAMRELNGKDVMGYELKLGW 80

                ...
gi 24651234  72 GRP 74
Cdd:cd12223  81 GKA 83

RNA recognition motif 2 (RRM2) found in granule-associated RNA binding proteins (p40-TIA-1 and TIAR), and yeast nuclear and cytoplasmic polyadenylated RNA-binding protein PUB1; This subfamily corresponds to the RRM3 of TIA-1, TIAR, and PUB1. Nucleolysin TIA-1 isoform p40 (p40-TIA-1 or TIA-1) and nucleolysin TIA-1-related protein (TIAR) are granule-associated RNA binding proteins involved in inducing apoptosis in cytotoxic lymphocyte (CTL) target cells. They share high sequence similarity and are expressed in a wide variety of cell types. TIA-1 can be phosphorylated by a serine/threonine kinase that is activated during Fas-mediated apoptosis.TIAR is mainly localized in the nucleus of hematopoietic and nonhematopoietic cells. It is translocated from the nucleus to the cytoplasm in response to exogenous triggers of apoptosis. Both TIA-1 and TIAR bind specifically to poly(A) but not to poly(C) homopolymers. They are composed of three N-terminal highly homologous RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a glutamine-rich C-terminal auxiliary domain containing a lysosome-targeting motif. TIA-1 and TIAR interact with RNAs containing short stretches of uridylates and their RRM2 can mediate the specific binding to uridylate-rich RNAs. The C-terminal auxiliary domain may be responsible for interacting with other proteins. In addition, TIA-1 and TIAR share a potential serine protease-cleavage site (Phe-Val-Arg) localized at the junction between their RNA binding domains and their C-terminal auxiliary domains. This subfamily also includes a yeast nuclear and cytoplasmic polyadenylated RNA-binding protein PUB1, termed ARS consensus-binding protein ACBP-60, or poly uridylate-binding protein, or poly(U)-binding protein, which has been identified as both a heterogeneous nuclear RNA-binding protein (hnRNP) and a cytoplasmic mRNA-binding protein (mRNP). It may be stably bound to a translationally inactive subpopulation of mRNAs within the cytoplasm. PUB1 is distributed in both, the nucleus and the cytoplasm, and binds to poly(A)+ RNA (mRNA or pre-mRNA). Although it is one of the major cellular proteins cross-linked by UV light to polyadenylated RNAs in vivo, PUB1 is nonessential for cell growth in yeast. PUB1 also binds to T-rich single stranded DNA (ssDNA); however, there is no strong evidence implicating PUB1 in the mechanism of DNA replication. PUB1 contains three RRMs, and a GAR motif (glycine and arginine rich stretch) that is located between RRM2 and RRM3.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234   7 VFVGSLPRCKPEE-LRRLFTNYGSVVECDV--MNRCAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:cd12354   3 VYVGNITKGLTEAlLQQTFSPFGQILEVRVfpDKGYAFIRFDSHEAATHAIVSVNGTIINGQAV 66

RNA recognition motif 1 (RRM1) found in Schizosaccharomyces pombe meiotically up-regulated gene 28 protein (Mug28) and similar proteins; Mug28 is a meiosis-specific protein that regulates spore wall formation. Members in this family contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the first RRM motif.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 24651234   7 VFVGSLPR-CKPEELRRLFTNYGSVVECDVMNR-------------CAFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd21620   4 LYVGNLPQtCQSEDLIILFEPYGNVCGAHIASRkkvkvswvkpsklFAFVEFETKEAATTAIVLLNGITYMGCQLKVE 81

RNA recognition motif (RRM) found in vertebrate RNA-binding Raly-like protein (RALYL); This subgroup corresponds to the RRM of RALYL, also termed heterogeneous nuclear ribonucleoprotein C-like 3, or hnRNP core protein C-like 3, a putative RNA-binding protein that shows high sequence homology with Raly, an RNA-binding protein playing a critical role in embryonic development. The biological role of RALYL remains unclear. Like Raly, RALYL contains two distinct domains, an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal auxiliary domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24651234   5 AKVFVGSLPR--CKPEELRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:cd12605   2 SRVFIGNLNTaiVKKADIEAIFAKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARIIAGQPL 66

RNA recognition motif 3 (RRM3) found in CELF/Bruno-like family of RNA binding proteins CELF1, CELF2, CELF3, CELF4, CELF5, CELF6 and similar proteins; This subgroup corresponds to the RRM3 of the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) proteins, a family of structurally related RNA-binding proteins involved in the regulation of pre-mRNA splicing in the nucleus and in the control of mRNA translation and deadenylation in the cytoplasm. The family contains six members: CELF-1 (also termed BRUNOL-2, or CUG-BP1, or NAPOR, or EDEN-BP), CELF-2 (also termed BRUNOL-3, or ETR-3, or CUG-BP2, or NAPOR-2), CELF-3 (also termed BRUNOL-1, or TNRC4, or ETR-1, or CAGH4, or ER DA4), CELF-4 (also termed BRUNOL-4), CELF-5 (also termed BRUNOL-5), CELF-6 (also termed BRUNOL-6). They all contain three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The low sequence conservation of the linker region is highly suggestive of a large variety in the co-factors that associate with the various CELF family members. Based on both sequence similarity and function, the CELF family can be divided into two subfamilies, the first containing CELFs 1 and 2, and the second containing CELFs 3, 4, 5, and 6. The different CELF proteins may act through different sites on at least some substrates. Furthermore, CELF proteins may interact with each other in varying combinations to influence alternative splicing in different contexts.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 24651234   7 VFVGSLP-RCKPEELRRLFTNYGSVVECDVM-------NRC-AFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12362   1 LFVYHLPnEFTDQDLYQLFAPFGNVVSAKVFvdkntgrSKGfGFVSYDNPLSAQAAIKAMNGFQVGGKRLKVQ 73

RNA recognition motif 3 (RRM3) found in RNA-binding protein 19 (RBM19) and similar proteins; This subgroup corresponds to the RRM3 of RBM19, also termed RNA-binding domain-1 (RBD-1), which is a nucleolar protein conserved in eukaryotes. It is involved in ribosome biogenesis by processing rRNA. In addition, it is essential for preimplantation development. RBM19 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        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 24651234   4 TAKVFVGSLP-RCKPEELRRLFTNYGSVVEC----DVMNR----CAFVHLENTDMAEAAIAALNGTIFKGQ 65
Cdd:cd12567   2 SGRLFVRNLPyTCTEEDLEKLFSKYGPLSEVhfpiDSLTKkpkgFAFVTYMIPEHAVKAYAELDGTVFQGR 72

RNA recognition motif 1 (RRM1) found in vertebrate paraspeckle protein 1 (PSP1); This subgroup corresponds to the RRM1 of PSPC1, also termed paraspeckle component 1 (PSPC1), a novel nucleolar factor that accumulates within a new nucleoplasmic compartment, termed paraspeckles, and diffusely distributes in the nucleoplasm. It is ubiquitously expressed and highly conserved in vertebrates. Its cellular function remains unknown currently, however, PSPC1 forms a novel heterodimer with the nuclear protein p54nrb, also known as non-POU domain-containing octamer-binding protein (NonO), which localizes to paraspeckles in an RNA-dependent manner. PSPC1 contains two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), at the N-terminus.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   6 KVFVGSLPR-CKPEELRRLFTNYGSVVECdVMNR---CAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:cd12586   3 RLFVGNLPTdITEEDFKRLFERYGEPSEV-FINRdrgFGFIRLESRTLAEIAKAELDGTILKSRPL 67

RNA recognition motif 3 (RRM3) found in yeast nuclear and cytoplasmic polyadenylated RNA-binding protein PUB1 and similar proteins; This subfamily corresponds to the RRM3 of yeast protein PUB1, also termed ARS consensus-binding protein ACBP-60, or poly uridylate-binding protein, or poly(U)-binding protein. PUB1 has been identified as both, a heterogeneous nuclear RNA-binding protein (hnRNP) and a cytoplasmic mRNA-binding protein (mRNP), which may be stably bound to a translationally inactive subpopulation of mRNAs within the cytoplasm. PUB1 is distributed in both, the nucleus and the cytoplasm, and binds to poly(A)+ RNA (mRNA or pre-mRNA). Although it is one of the major cellular proteins cross-linked by UV light to polyadenylated RNAs in vivo, PUB1 is nonessential for cell growth in yeast. PUB1 also binds to T-rich single stranded DNA (ssDNA); however, there is no strong evidence implicating PUB1 in the mechanism of DNA replication. PUB1 contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a GAR motif (glycine and arginine rich stretch) that is located between RRM2 and RRM3.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 24651234   7 VFVGSL-PRCKPEELRRLFTNYGSVVECDVMNR--CAFVHLENTDMAEAAIAALNGTIFKGQPI 67
Cdd:cd12622   3 VYVGNLpPEVTQADLIPLFQNFGVIEEVRVQRDkgFGFVKYDTHEEAALAIQQLNGQPFLGRPI 66

RNA recognition motif 2 (RRM2) found in CUGBP Elav-like family member CELF-1, CELF-2 and similar proteins; This subgroup corresponds to the RRM2 of CELF-1 (also termed BRUNOL-2, or CUG-BP1, or EDEN-BP), CELF-2 (also termed BRUNOL-3, or ETR-3, or CUG-BP2, or NAPOR), both of which belong to the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) family of RNA-binding proteins that have been implicated in the regulation of pre-mRNA splicing and in the control of mRNA translation and deadenylation. CELF-1 is strongly expressed in all adult and fetal tissues tested. Human CELF-1 is a nuclear and cytoplasmic RNA-binding protein that regulates multiple aspects of nuclear and cytoplasmic mRNA processing, with implications for onset of type 1 myotonic dystrophy (DM1), a neuromuscular disease associated with an unstable CUG triplet expansion in the 3'-UTR (3'-untranslated region) of the DMPK (myotonic dystrophy protein kinase) gene; it preferentially targets UGU-rich mRNA elements. It has been shown to bind to a Bruno response element, a cis-element involved in translational control of oskar mRNA in Drosophila, and share sequence similarity to Bruno, the Drosophila protein that mediates this process. The Xenopus homolog embryo deadenylation element-binding protein (EDEN-BP) mediates sequence-specific deadenylation of Eg5 mRNA. It binds specifically to the EDEN motif in the 3'-untranslated regions of maternal mRNAs and targets these mRNAs for deadenylation and translational repression. CELF-1 contains three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The two N-terminal RRMs of EDEN-BP are necessary for the interaction with EDEN as well as a part of the linker region (between RRM2 and RRM3). Oligomerization of EDEN-BP is required for specific mRNA deadenylation and binding. CELF-2 is expressed in all tissues at some level, but highest in brain, heart, and thymus. It has been implicated in the regulation of nuclear and cytoplasmic RNA processing events, including alternative splicing, RNA editing, stability and translation. CELF-2 shares high sequence identity with CELF-1, but shows different binding specificity; it preferentially binds to sequences with UG repeats and UGUU motifs. It has been shown to bind to a Bruno response element, a cis-element involved in translational control of oskar mRNA in Drosophila, and share sequence similarity to Bruno, the Drosophila protein that mediates this process. It also binds to the 3'-UTR of cyclooxygenase-2 messages, affecting both translation and mRNA stability, and binds to apoB mRNA, regulating its C to U editing. CELF-2 also contains three highly conserved RRMs. It binds to RNA via the first two RRMs, which are also important for localization in the cytoplasm. The splicing activation or repression activity of CELF-2 on some specific substrates is mediated by RRM1/RRM2. Both, RRM1 and RRM2 of CELF-2, can activate cardiac troponin T (cTNT) exon 5 inclusion. In addition, CELF-2 possesses a typical arginine and lysine-rich nuclear localization signal (NLS) in the C-terminus, within RRM3.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 24651234   6 KVFVGSLPR-CKPEELRRLFTNYGSVVEC------DVMNR-CAFVHLENTDMAEAAIAALN-GTIFKG--QPIVVE 70
Cdd:cd12634   3 KLFIGMVSKkCNENDIRVMFSPFGQIEECrilrgpDGLSRgCAFVTFSTRAMAQNAIKAMHqSQTMEGcsSPIVVK 78

RNA recognition motif 1 (RRM1) found in the U1A/U2B"/SNF protein family; This subfamily corresponds to the RRM1 of U1A/U2B"/SNF protein family which contains Drosophila sex determination protein SNF and its two mammalian counterparts, U1 small nuclear ribonucleoprotein A (U1 snRNP A or U1-A or U1A) and U2 small nuclear ribonucleoprotein B" (U2 snRNP B" or U2B"), all of which consist of two RNA recognition motifs (RRMs), connected by a variable, flexible linker. SNF is an RNA-binding protein found in the U1 and U2 snRNPs of Drosophila where it is essential in sex determination and possesses a novel dual RNA binding specificity. SNF binds with high affinity to both Drosophila U1 snRNA stem-loop II (SLII) and U2 snRNA stem-loop IV (SLIV). It can also bind to poly(U) RNA tracts flanking the alternatively spliced Sex-lethal (Sxl) exon, as does Drosophila Sex-lethal protein (SXL). U1A is an RNA-binding protein associated with the U1 snRNP, a small RNA-protein complex involved in pre-mRNA splicing. U1A binds with high affinity and specificity to stem-loop II (SLII) of U1 snRNA. It is predominantly a nuclear protein that shuttles between the nucleus and the cytoplasm independently of interactions with U1 snRNA. Moreover, U1A may be involved in RNA 3'-end processing, specifically cleavage, splicing and polyadenylation, through interacting with a large number of non-snRNP proteins. U2B", initially identified to bind to stem-loop IV (SLIV) at the 3' end of U2 snRNA, is a unique protein that comprises of the U2 snRNP. Additional research indicates U2B" binds to U1 snRNA stem-loop II (SLII) as well and shows no preference for SLIV or SLII on the basis of binding affinity. Moreover, U2B" does not require an auxiliary protein for binding to RNA, and its nuclear transport is independent of U2 snRNA binding.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 24651234  16 KPEELRR----LFTNYGSVVECdVMNRC------AFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12246  12 KKDELKRslyaLFSQFGPVLDI-VASKSlkmrgqAFVVFKDVESATNALRALQGFPFYGKPMRIQ 75

RNA recognition motif 3 (RRM3) found in RNA-binding protein 19 (RBM19) and RNA recognition motif 2 found in multiple RNA-binding domain-containing protein 1 (MRD1); This subfamily corresponds to the RRM3 of RBM19 and RRM2 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). MRD1 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). It is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. MRD1 contains 5 conserved RRMs, which may play an important structural role in organizing specific rRNA processing events.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 24651234   6 KVFVGSLP-RCKPEELRRLFTNYGSVVECDVM--------NRCAFVHLENTDMAEAAIAALNGTIFKG 64
Cdd:cd12316   1 RLFVRNLPfTATEDELRELFEAFGKISEVHIPldkqtkrsKGFAFVLFVIPEDAVKAYQELDGSIFQG 68

RNA recognition motif 3 (RRM3) found in vertebrate heterogeneous nuclear ribonucleoprotein Q (hnRNP Q); This subgroup corresponds to the RRM3 of hnRNP Q, also termed glycine- and tyrosine-rich RNA-binding protein (GRY-RBP), or NS1-associated protein 1 (NASP1), or synaptotagmin-binding, cytoplasmic RNA-interacting protein (SYNCRIP). It is a ubiquitously expressed nuclear RNA-binding protein identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome. As an alternatively spliced version of NSAP, it acts as an interaction partner of a multifunctional protein required for viral replication, and is implicated in the regulation of specific mRNA transport. hnRNP Q has also been identified as SYNCRIP that is a dual functional protein participating in both viral RNA replication and translation. As a synaptotagmin-binding protein, hnRNP Q plays a putative role in organelle-based mRNA transport along the cytoskeleton. Moreover, hnRNP Q has been found in protein complexes involved in translationally coupled mRNA turnover and mRNA splicing. It functions as a wild-type survival motor neuron (SMN)-binding protein that may participate in pre-mRNA splicing and modulate mRNA transport along microtubuli. hnRNP Q contains an acidic auxiliary N-terminal region, followed by two well defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RGG motif; hnRNP Q binds RNA through its RRM domains.

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gi 24651234   7 VFVGSLPRCKPEE-LRRLFTNYGSVVECDVMNRCAFVHLENTDMAEAAIAALNGTIFKGQPIVVEAGRP 74
Cdd:cd12495   4 LFVRNLANTVTEEiLEKAFSQFGKLERVKKLKDYAFIHFDERDGAVKAMDEMNGKDLEGENIEIVFAKP 72

RNA recognition motif (RRM) found in transformer-2 protein homolog TRA2-alpha, TRA2-beta and similar proteins; This subfamily corresponds to the RRM of two mammalian homologs of Drosophila transformer-2 (Tra2), TRA2-alpha, TRA2-beta (also termed SFRS10), and similar proteins found in eukaryotes. TRA2-alpha is a 40-kDa serine/arginine-rich (SR) protein that specifically binds to gonadotropin-releasing hormone (GnRH) exonic splicing enhancer on exon 4 (ESE4) and is necessary for enhanced GnRH pre-mRNA splicing. It strongly stimulates GnRH intron A excision in a dose-dependent manner. In addition, TRA2-alpha can interact with either 9G8 or SRp30c, which may also be crucial for ESE-dependent GnRH pre-mRNA splicing. TRA2-beta is a serine/arginine-rich (SR) protein that controls the pre-mRNA alternative splicing of the calcitonin/calcitonin gene-related peptide (CGRP), the survival motor neuron 1 (SMN1) protein and the tau protein. Both, TRA2-alpha and TRA2-beta, contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), flanked by the N- and C-terminal arginine/serine (RS)-rich regions.

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gi 24651234  18 EELRRLFTNYGSVVECDV-------MNRC-AFVHLENTDMAEAAIAALNGTIFKGQPIVVE 70
Cdd:cd12363  16 RDLREVFSRYGPIEKVQVvydqqtgRSRGfGFVYFESVEDAKEAKERLNGQEIDGRRIRVD 76