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 61966711    18 VFIGNLNTlVVKKSDVEAIFSKYGKIAGCSV-------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVV 80
Cdd:pfam00076   1 LFVGNLPP-DTTEEDLKDLFSKFGPIKSIRLvrdetgrSKGFAFVEFEDEEDAEKAIEALNGKELGGREL 69

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 61966711  13 SMNsrVFIGNLNTLVvKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINL 84
Cdd:COG0724   1 SMK--IYVGNLPYSV-TEEDLRELFSEYGEVTSVKLitdretgrSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKVNE 77

                ....*....
gi 61966711  85 aAEPKVNRG 93
Cdd:COG0724  78 -ARPREERP 85

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 61966711  15 NSRVFIGNLNTLVVKKSDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLAAEPK 89
Cdd:cd12604   1 NSRVFIGNLNTAVVKKSDVETIFSKYGRVVGCSVHKGYAFVQYTNERHARAAVIGENGRVLAGQTLDINMAGEPK 75

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 61966711  15 NSRVFIGNLNTLVVKKSDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDIN 83
Cdd:cd12605   1 NSRVFIGNLNTAIVKKADIEAIFAKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARIIAGQPLDIN 69

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 61966711    18 VFIGNLNTlVVKKSDVEAIFSKYGKIAGCSV-------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVV 80
Cdd:pfam00076   1 LFVGNLPP-DTTEEDLKDLFSKFGPIKSIRLvrdetgrSKGFAFVEFEDEEDAEKAIEALNGKELGGREL 69

RNA recognition motif (RRM) found in serine/arginine-rich splicing factor 3 (SRSF3) and similar proteins; This subfamily corresponds to the RRM of two serine/arginine (SR) proteins, serine/arginine-rich splicing factor 3 (SRSF3) and serine/arginine-rich splicing factor 7 (SRSF7). SRSF3, also termed pre-mRNA-splicing factor SRp20, modulates alternative splicing by interacting with RNA cis-elements in a concentration- and cell differentiation-dependent manner. It is also involved in termination of transcription, alternative RNA polyadenylation, RNA export, and protein translation. SRSF3 is critical for cell proliferation, and tumor induction and maintenance. It can shuttle between the nucleus and cytoplasm. SRSF7, also termed splicing factor 9G8, plays a crucial role in both constitutive splicing and alternative splicing of many pre-mRNAs. Its localization and functions are tightly regulated by phosphorylation. SRSF7 is predominantly present in the nuclear and can shuttle between nucleus and cytoplasm. It cooperates with the export protein, Tap/NXF1, helps mRNA export to the cytoplasm, and enhances the expression of unspliced mRNA. Moreover, SRSF7 inhibits tau E10 inclusion through directly interacting with the proximal downstream intron of E10, a clustering region for frontotemporal dementia with Parkinsonism (FTDP) mutations. Both SRSF3 and SRSF7 contain a single N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal RS domain rich in serine-arginine dipeptides. The RRM domain is involved in RNA binding, and the RS domain has been implicated in protein shuttling and protein-protein interactions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 61966711  17 RVFIGNLNTLVvKKSDVEAIFSKYGKIAGCSVHK---GFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12373   1 KVYVGNLGPRV-TKRELEDAFEKYGPLRNVWVARnppGFAFVEFEDPRDAEDAVRALDGRRICGSRVRVELS 71

RNA recognition motif 1 (RRM1) found in serine/arginine-rich splicing factor 1 (SRSF1) and similar proteins; This subgroup corresponds to the RRM1 in three serine/arginine (SR) proteins: serine/arginine-rich splicing factor 1 (SRSF1 or ASF-1), serine/arginine-rich splicing factor 9 (SRSF9 or SRp30C), and plant pre-mRNA-splicing factor SF2 (SR1). SRSF1 is a shuttling SR protein involved in constitutive and alternative splicing, nonsense-mediated mRNA decay (NMD), mRNA export and translation. It also functions as a splicing-factor oncoprotein that regulates apoptosis and proliferation to promote mammary epithelial cell transformation. SRSF9 has been implicated in the activity of many elements that control splice site selection, the alternative splicing of the glucocorticoid receptor beta in neutrophils and in the gonadotropin-releasing hormone pre-mRNA. It can also interact with other proteins implicated in alternative splicing, including YB-1, rSLM-1, rSLM-2, E4-ORF4, Nop30, and p32. Both, SRSF1 and SRSF9, contain two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RS domains rich in serine-arginine dipeptides. In contrast, SF2 contains two N-terminal RRMs and a C-terminal PSK domain rich in proline, serine and lysine residues.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 61966711  17 RVFIGNLNTLVvKKSDVEAIFSKYGKIAGCSVHKG-----FAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12338   1 RIYVGNLPGDI-RERDIEDLFYKYGPILAIDLKNRrrgppFAFVEFEDPRDAEDAIRGRDG 60

RNA recognition motif 2 (RRM2) found in vertebrate RRM-containing coactivator activator/modulator (CoAA); This subgroup corresponds to the RRM2 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 61966711  17 RVFIGNLNTlVVKKSDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINL 84
Cdd:cd12609   2 KIFVGNVSA-TCTSDELRGLFEEFGRVVECDKVKDYAFVHMEREEEALAAIEALNGKEVKGRRINVEL 68

RNA recognition motif 1 (RRM1) found in vertebrate serine/arginine-rich splicing factor 5 (SRSF5); This subgroup corresponds to the RRM1 of SRSF5, also termed delayed-early protein HRS, or pre-mRNA-splicing factor SRp40, or splicing factor, arginine/serine-rich 5 (SFRS5). SFSF5 is an essential splicing regulatory serine/arginine (SR) protein that 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 it is necessary for enhancer activation. SRSF5 also functions as a factor required for insulin-regulated splice site selection for protein kinase C (PKC) betaII mRNA. It is involved in the regulation of PKCbetaII exon inclusion by insulin via its increased phosphorylation by a phosphatidylinositol 3-kinase (PI 3-kinase) signaling pathway. Moreover, SRSF5 can regulate alternative splicing in exon 9 of glucocorticoid receptor pre-mRNA in a dose-dependent manner. SRSF5 contains 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. The specific RNA binding by SRSF5 requires the phosphorylation of its SR domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 61966711  17 RVFIGNLNTLVVKKsDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12595   1 RVFIGRLNPAAREK-DVERFFKGYGRIRDIDLKRGFGFVEFEDPRDADDAVYELDGKELCNERVTIEHA 68

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
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 61966711  18 VFIGNLNTLVVKkSDVEAIFSKYGKIAGCS-VHK-----GFAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12454   6 IFVGQLDPKTTD-SELFRRFSKYGKIVDCKlIKRpepvnAFAFLRFESEEAAEAAVEEENH 65

RNA recognition motif 1 (RRM1) found in plant pre-mRNA-splicing factor SF2 and similar proteins; This subgroup corresponds to the RRM1 of SF2, also termed SR1 protein, a plant serine/arginine (SR)-rich phosphoprotein similar to the mammalian splicing factor SF2/ASF. It promotes splice site switching in mammalian nuclear extracts. SF2 contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a C-terminal domain rich in proline, serine and lysine residues (PSK domain), a composition reminiscent of histones. This PSK domain harbors a putative phosphorylation site for the mitotic kinase cyclin/p34cdc2.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 61966711  17 RVFIGNLnTLVVKKSDVEAIFSKYGKIAGCSVH-----KGFAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12599   1 RVYVGNL-PMDIREREVEDLFSKYGPVVSIDLKipprpPAYAFVEFEDARDAEDAIRGRDG 60

RNA recognition motif (RRM) found in eukaryotic RNA-binding protein 18 and similar proteins; This subfamily corresponds to the RRM of RBM18, a putative RNA-binding protein containing a well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). The biological role of RBM18 remains unclear.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 61966711  17 RVFIGNLNTLVVKKsDVEAIFSKYGKI---------AGCSVHK--GFAFVQYDKEKNARAAVAGEDGRMIASQ--VVD 81
Cdd:cd12355   1 RLWIGNLDPRLTEY-HLLKLLSKYGKIkkfdflfhkTGPLKGQprGYCFVTFETKEEAEKAIECLNGKLALGKklVVR 77

RNA recognition motif 1 (RRM1) found in La-related protein 7 (LARP7) and similar proteins; This subfamily corresponds to the RRM1 of LARP7, also termed La ribonucleoprotein domain family member 7, or P-TEFb-interaction protein for 7SK stability (PIP7S), an oligopyrimidine-binding protein that binds to the highly conserved 3'-terminal U-rich stretch (3' -UUU-OH) of 7SK RNA. LARP7 is a stable component of the 7SK small nuclear ribonucleoprotein (7SK snRNP). It intimately associates with all the nuclear 7SK and is required for 7SK stability. LARP7 also acts as a negative transcriptional regulator of cellular and viral polymerase II genes, acting by means of the 7SK snRNP system. It plays an essential role in the inhibition of positive transcription elongation factor b (P-TEFb)-dependent transcription, which has been linked to the global control of cell growth and tumorigenesis. LARP7 contains a La motif (LAM) and an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), at the N-terminal region, which mediates binding to the U-rich 3' terminus of 7SK RNA. LARP7 also carries another putative RRM domain at its C-terminus.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 61966711  31 SDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAG 69
Cdd:cd12290  14 EWIEAVFSKYGEVVYVSIprykstgdPKGFAFIEFETSESAQKAVKH 60

RNA recognition motif 2 (RRM2) found in yeast multiple RNA-binding domain-containing protein 1 (MRD1) and similar proteins; This subgroup corresponds to the RRM2 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). It is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. MRD1 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 61966711  16 SRVFIGNLnTLVVKKSDVEAIFSKYGKIAgcSVH----------KGFAFVQYDKEKNARAAVAGED-----GRMI 75
Cdd:cd12566   3 GRLFLRNL-PYSTKEDDLQKLFSKFGEVS--EVHvpidkktkksKGFAYVLFLDPEDAVQAYNELDgkvfqGRLI 74

RNA recognition motif (RRM) found in fission yeast pre-mRNA-splicing factor Srp1p, Arabidopsis thaliana arginine/serine-rich-splicing factor RSp31 and similar proteins; This subfamily corresponds to the RRM of Srp1p and RRM2 of plant SR splicing factors. Srp1p is encoded by gene srp1 from fission yeast Schizosaccharomyces pombe. It plays a role in the pre-mRNA splicing process, but is not essential for growth. Srp1p is closely related to the SR protein family found in Metazoa. It contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a glycine hinge and a RS domain in the middle, and a C-terminal domain. The family also includes a novel group of arginine/serine (RS) or serine/arginine (SR) splicing factors existing in plants, such as A. thaliana RSp31, RSp35, RSp41 and similar proteins. Like vertebrate RS splicing factors, these proteins function as plant splicing factors and play crucial roles in constitutive and alternative splicing in plants. They all contain two RRMs at their N-terminus and an RS domain at their C-terminus.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 61966711  18 VFIGNLNTLVVKKSDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLAA 86
Cdd:cd12233   2 LFVVGFDPGTTREEDIEKLFEPFGPLVRCDIRKTFAFVEFEDSEDATKALEALHGSRIDGSVLTVEFVK 70

RNA recognition motif 3 (RRM3) found in Schizosaccharomyces pombe mRNA export factor Crp79, meiotically up-regulated gene 28 protein (Mug28) and similar proteins; Crp79, also called meiotic expression up-regulated protein 5 (Mug5), or polyadenylate-binding protein crp79, or PABP, or poly(A)-binding protein, is an auxiliary mRNA export factor that binds the poly(A) tail of mRNA and is involved in the export of mRNA from the nucleus to the cytoplasm. 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 three RRM motif.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 61966711  18 VFIGNLN-TLVVKKSDVEAIFSKYGKIAGC--------SVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLaAEP 88
Cdd:cd21622   6 LFVKNLDdTVITNKEDLEQLFSPFGQIVSSylatypgtGISKGFGFVAFSKPEDAAKAKETLNGVMVGRKRIFVSY-AER 84

                ....
gi 61966711  89 KVNR 92
Cdd:cd21622  85 KEDR 88

RNA recognition motif (RRM) found in U11/U12 small nuclear ribonucleoprotein 35 kDa protein (U11/U12-35K) and similar proteins; This subfamily corresponds to the RRM of U11/U12-35K, also termed protein HM-1, or U1 snRNP-binding protein homolog, and is one of the components of the U11/U12 snRNP, which is a subunit of the minor (U12-dependent) spliceosome required for splicing U12-type nuclear pre-mRNA introns. U11/U12-35K is highly conserved among bilateria and plants, but lacks in some organisms, such as Saccharomyces cerevisiae and Caenorhabditis elegans. Moreover, U11/U12-35K shows significant sequence homology to U1 snRNP-specific 70 kDa protein (U1-70K or snRNP70). It contains a conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), followed by an adjacent glycine-rich region, and Arg-Asp and Arg-Glu dipeptide repeats rich domain, making U11/U12-35K a possible functional analog of U1-70K. It may facilitate 5' splice site recognition in the minor spliceosome and play a role in exon bridging, interacting with components of the major spliceosome bound to the pyrimidine tract of an upstream U2-type intron. The family corresponds to the RRM of U11/U12-35K that may directly contact the U11 or U12 snRNA through the RRM domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 61966711  10 DPHSMnsrVFIGNLNtLVVKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAA 66
Cdd:cd12237   2 DPRLT---LFVGRLS-LQTTEEKLKEVFSRYGDIRRLRLvrdivtgfSKRYAFIEYKEERDALHA 62

RNA recognition motif 2 (RRM2) found found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM2 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 a 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. Moreover, 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. 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        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 61966711  18 VFIGNLNTLVVKKSdVEAIFSKYGKIAGCSV-------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVV 80
Cdd:cd12379   5 IFIKNLDKSIDNKA-LYDTFSAFGNILSCKVatdenggSKGYGFVHFETEEAAERAIEKVNGMLLNGKKV 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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 61966711  17 RVFIGNLnTLVVKKSDVEAIFSKYGKIAgcSVH----------KGFAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12567   4 RLFVRNL-PYTCTEEDLEKLFSKYGPLS--EVHfpidsltkkpKGFAFVTYMIPEHAVKAYAELDG 66

RNA recognition motif (RRM) found in U1 small nuclear ribonucleoprotein 70 kDa (U1-70K) and similar proteins; This subfamily corresponds to the RRM of U1-70K, also termed snRNP70, a key component of the U1 snRNP complex, which is one of the key factors facilitating the splicing of pre-mRNA via interaction at the 5' splice site, and is involved in regulation of polyadenylation of some viral and cellular genes, enhancing or inhibiting efficient poly(A) site usage. U1-70K plays an essential role in targeting the U1 snRNP to the 5' splice site through protein-protein interactions with regulatory RNA-binding splicing factors, such as the RS protein ASF/SF2. Moreover, U1-70K protein can specifically bind to stem-loop I of the U1 small nuclear RNA (U1 snRNA) contained in the U1 snRNP complex. It also mediates the binding of U1C, another U1-specific protein, to the U1 snRNP complex. U1-70K contains a conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), followed by an adjacent glycine-rich region at the N-terminal half, and two serine/arginine-rich (SR) domains at the C-terminal half. The RRM is responsible for the binding of stem-loop I of U1 snRNA molecule. Additionally, the most prominent immunodominant region that can be recognized by auto-antibodies from autoimmune patients may be located within the RRM. The SR domains are involved in protein-protein interaction with SR proteins that mediate 5' splice site recognition. For instance, the first SR domain is necessary and sufficient for ASF/SF2 Binding. The family also includes Drosophila U1-70K that is an essential splicing factor required for viability in flies, but its SR domain is dispensable. The yeast U1-70k doesn't contain easily recognizable SR domains and shows low sequence similarity in the RRM region with other U1-70k proteins and therefore not included in this family. The RRM domain is dispensable for yeast U1-70K function.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 61966711  19 FIGNLNtLVVKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDGRMIASQ--VVDI 82
Cdd:cd12236   5 FVARLS-YDTTESKLRREFEKYGPIKRVRLvrdkktgkSRGYAFIEFEHERDMKAAYKHADGKKIDGRrvLVDV 77

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 61966711  17 RVFIGNLNTLVVKKSdVEAIFSKYGKIA--------GCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12382   3 KLFIGGLNTETNEKA-LEAVFGKYGRIVevllmkdrETNKSRGFAFVTFESPADAKDAARDMNGKELDGKAIKVEQA 78

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 61966711  17 RVFIGNLnTLVVKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd21608   1 KLYVGNL-SWDTTEDDLRDLFSEFGEVESAKVitdretgrSRGFGFVTFSTAEAAEAAIDALNGKELDGRSIVVNEA 76

RNA recognition motif 1 (RRM1) found in vertebrate serine/arginine-rich splicing factor 9 (SRSF9); This subgroup corresponds to the RRM1 of SRSF9, also termed pre-mRNA-splicing factor SRp30C. SRSF9 is an essential splicing regulatory serine/arginine (SR) protein that has been implicated in the activity of many elements that control splice site selection, the alternative splicing of the glucocorticoid receptor beta in neutrophils and in the gonadotropin-releasing hormone pre-mRNA. SRSF9 can also interact with other proteins implicated in alternative splicing, including YB-1, rSLM-1, rSLM-2, E4-ORF4, Nop30, and p32. SRSF9 contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by an unusually short C-terminal RS domains rich in serine-arginine dipeptides.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 61966711  17 RVFIGNLNTLVVKKsDVEAIFSKYGKIAGCSVHKG-----FAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12598   1 RIYVGNLPSDVREK-DLEDLFYKYGRIRDIELKNRrglvpFAFVRFEDPRDAEDAVFGRNG 60

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
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 61966711  18 VFIGNLnTLVVKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVA 68
Cdd:cd12413   2 LFVRNL-PYDTTDEQLEELFSDVGPVKRCFVvkdkgkdkCRGFGYVTFALAEDAQRALE 59

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 61966711  17 RVFIGNLnTLVVKKSDVEAIFSKYGKIAGCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12596   3 RVYIGRL-SYHVREKDIQRFFSGYGKLLEVDLKNGYGFVEFEDSRDADDAVYELNGKELCGERVIVEHA 70

RNA recognition motif (RRM) found in RNA-binding protein with serine-rich domain 1 (RNPS1) and similar proteins; This subfamily corresponds to the RRM of RNPS1 and its eukaryotic homologs. RNPS1, also termed RNA-binding protein prevalent during the S phase, or SR-related protein LDC2, was originally characterized as a general pre-mRNA splicing activator, which activates both constitutive and alternative splicing of pre-mRNA in vitro.It has been identified as a protein component of the splicing-dependent mRNP complex, or exon-exon junction complex (EJC), and is directly involved in mRNA surveillance. Furthermore, RNPS1 is a splicing regulator whose activator function is controlled in part by CK2 (casein kinase II) protein kinase phosphorylation. It can also function as a squamous-cell carcinoma antigen recognized by T cells-3 (SART3)-binding protein, and is involved in the regulation of mRNA splicing. RNPS1 contains an N-terminal serine-rich (S) domain, a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and the C-terminal arginine/serine/proline-rich (RS/P) domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 61966711  18 VFIGNLnTLVVKKSDVEAIFSKYGKIA--------GCSVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVV 80
Cdd:cd12365   1 LHVGKL-TRNVTKDHLKEIFSVYGTVKnvdlpidrEPNLPRGYAYVEFESPEDAEKAIKHMDGGQIDGQEV 70

RNA recognition motif 1 (RRM1) found in vertebrate 54 kDa nuclear RNA- and DNA-binding protein (p54nrb); This subgroup corresponds to the RRM1 of p54nrb, also termed non-POU domain-containing octamer-binding protein (NonO), or 55 kDa nuclear protein (NMT55), or DNA-binding p52/p100 complex 52 kDa subunit. p54nrb is a multifunctional 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. It is ubiquitously expressed and highly conserved in vertebrates. p54nrb binds both, single- and double-stranded RNA and DNA, and also possesses inherent carbonic anhydrase activity. It forms a heterodimer with paraspeckle component 1 (PSPC1 or PSP1), localizing to paraspeckles in an RNA-dependent manneras well as with polypyrimidine tract-binding protein-associated-splicing factor (PSF). p54nrb 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
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 61966711  16 SRVFIGNLNTLVVKKsDVEAIFSKYGKIAGCSVHK--GFAFVQYDKEKNARAAVAGED 71
Cdd:cd12588   2 SRLFVGNLPPDITEE-EMRKLFEKYGKAGEVFIHKdkGFGFIRLETRTLAEIAKVELD 58

RNA recognition motif 1 (RRM1) found in plant Mei2-like proteins; This subgroup corresponds to the RRM1 of Mei2-like proteins that represent an ancient eukaryotic RNA-binding proteins family. Their corresponding Mei2-like genes appear to have arisen early in eukaryote evolution, been lost from some lineages such as Saccharomyces cerevisiae and metazoans, and diversified in the plant lineage. The plant Mei2-like genes may function in cell fate specification during development, rather than as stimulators of meiosis. Members in this family contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The C-terminal RRM (RRM3) is unique to Mei2-like proteins and it is highly conserved between plants and fungi. Up to date, the intracellular localization, RNA target(s), cellular interactions and phosphorylation states of Mei2-like proteins in plants remain unclear.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 61966711  16 SRV-FIGNLNTlVVKKSDVEAIFSKYGKI----AGCsVHKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDI 82
Cdd:cd12524   1 SRTlFVRNINS-SVEDEELRALFEQFGEIrtlyTAC-KHRGFIMVSYYDIRAAQSAKRALQGTELGGRKLDI 70

RNA recognition motif (RRM) found in RNA-binding protein RBM8A, RBM8B nd similar proteins; This subfamily corresponds to the RRM of RBM8, also termed binder of OVCA1-1 (BOV-1), or RNA-binding protein Y14, which is one of the components of the exon-exon junction complex (EJC). It has two isoforms, RBM8A and RBM8B, both of which are identical except that RBM8B is 16 amino acids shorter at its N-terminus. RBM8, together with other EJC components (such as Magoh, Aly/REF, RNPS1, Srm160, and Upf3), plays critical roles in postsplicing processing, including nuclear export and cytoplasmic localization of the mRNA, and the nonsense-mediated mRNA decay (NMD) surveillance process. RBM8 binds to mRNA 20-24 nucleotides upstream of a spliced exon-exon junction. It is also involved in spliced mRNA nuclear export, and the process of nonsense-mediated decay of mRNAs with premature stop codons. RBM8 forms a specific heterodimer complex with the EJC protein Magoh which then associates with Aly/REF, RNPS1, DEK, and SRm160 on the spliced mRNA, and inhibits ATP turnover by eIF4AIII, thereby trapping the EJC core onto RNA. RBM8 contains an N-terminal putative bipartite nuclear localization signal, one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), in the central region, and a C-terminal serine-arginine rich region (SR domain) and glycine-arginine rich region (RG domain).

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 61966711  32 DVEAIFSKYGKIAGCSVH--------KGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12324  22 DIHDKFAEFGEIKNLHLNldrrtgfvKGYALVEYETKKEAQAAIEGLNGKELLGQTISVDWA 83

RNA recognition motif 1 (RRM1) found in yeast nucleolar protein 3 (Npl3p) and similar proteins; This subfamily corresponds to the RRM1 of Npl3p, also termed mitochondrial targeting suppressor 1 protein, or nuclear polyadenylated RNA-binding protein 1. Npl3p is a major yeast RNA-binding protein that competes with 3'-end processing factors, such as Rna15, for binding to the nascent RNA, protecting the transcript from premature termination and coordinating transcription termination and the packaging of the fully processed transcript for export. It specifically recognizes a class of G/U-rich RNAs. Npl3p is a multi-domain protein containing two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), separated by a short linker and a C-terminal domain rich in glycine, arginine and serine residues.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 61966711  17 RVFIGNLnTLVVKKSDVEAIFSKYGKIAGCSV--HKGFAFVQYDKEKNARAAVAGEDGRMIASQ 78
Cdd:cd12340   1 RLFVRPF-PPDTSESAIREIFSPYGPVKEVKMlsDSNFAFVEFEELEDAIRAKDSVHGRVLNNE 63

RNA recognition motif (RRM) found in nucleolar protein 8 (NOL8) and similar proteins; This model corresponds to the RRM of NOL8 (also termed Nop132) encoded by a novel NOL8 gene that is up-regulated in the majority of diffuse-type, but not intestinal-type, gastric cancers. Thus, NOL8 may be a good molecular target for treatment of diffuse-type gastric cancer. Also, NOL8 is a phosphorylated protein that contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), suggesting NOL8 is likely to function as a novel RNA-binding protein. It may be involved in regulation of gene expression at the post-transcriptional level or in ribosome biogenesis in cancer cells.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 61966711  17 RVFIGNLNtLVVKKSDVEAIFSKYGKIAGCSVH-------KGFAFVQYD 58
Cdd:cd12226   1 RLFVGGLS-PSITEDDLERRFSRFGTVSDVEIIrkkdapdRGFAYIDLR 48

RNA recognition motif (RRM) found in vertebrate serine/arginine-rich splicing factor 3 (SRSF3); This subgroup corresponds to the RRM of SRSF3, also termed pre-mRNA-splicing factor SRp20, a splicing regulatory serine/arginine (SR) protein that modulates alternative splicing by interacting with RNA cis-elements in a concentration- and cell differentiation-dependent manner. It is also involved in termination of transcription, alternative RNA polyadenylation, RNA export, and protein translation. SRSF3 is critical for cell proliferation and tumor induction and maintenance. SRSF3 can shuttle between the nucleus and cytoplasm. It contains a single N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal RS domain rich in serine-arginine dipeptides. The RRM domain is involved in RNA binding, and the RS domain has been implicated in protein shuttling and protein-protein interactions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 61966711  14 MNSRVFIGNLNTlVVKKSDVEAIFSKYGKIAGCSVHK---GFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12645   3 LDCKVYVGNLGN-NGNKTELERAFGYYGPLRSVWVARnppGFAFVEFEDPRDAADAVRELDGRTLCGCRVRVELS 76

RNA recognition motif 2 (RRM2) found in vertebrate Hu-antigen R (HuR); This subgroup corresponds to the RRM2 of HuR, also termed ELAV-like protein 1 (ELAV-1), the ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. HuR has an anti-apoptotic function during early cell stress response. It binds to mRNAs and enhances the expression of several anti-apoptotic proteins, such as p21waf1, p53, and prothymosin alpha. HuR also has pro-apoptotic function by promoting apoptosis when cell death is unavoidable. Furthermore, HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation. Like other Hu proteins, HuR contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 61966711  30 KSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDGRMI--ASQVVDINLAAEP 88
Cdd:cd12773  14 QKDVEDMFSRFGRIINSRVlvdqatglSRGVAFIRFDKRSEAEEAITNFNGHKPpgSSEPITVKFAANP 82

RNA recognition motif 4 (RRM4) found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM4 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 theThe CD corresponds to the RRM. 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. Moreover, 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
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 61966711  37 FSKYGKIAGCSV-------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12381  22 FSPFGTITSAKVmtdeggrSKGFGFVCFSSPEEATKAVTEMNGRIIGGKPLYVALA 77

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 61966711    12 HSMNSRVFIGNLNTlVVKKSDVEAIFSKYGKIAGCSV-------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINL 84
Cdd:TIGR01628 282 KAQGVNLYVKNLDD-TVTDEKLRELFSECGEITSAKVmldekgvSRGFGFVCFSNPEEANRAVTEMHGRMLGGKPLYVAL 360

                  .
gi 61966711    85 A 85
Cdd:TIGR01628 361 A 361

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
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 61966711  31 SDVEAIFSKYGKIAGCSVH--------KGFAFVQYDKEKNARAAVAGEDGRMIASQV 79
Cdd:cd12362  13 QDLYQLFAPFGNVVSAKVFvdkntgrsKGFGFVSYDNPLSAQAAIKAMNGFQVGGKR 69

RNA recognition motif 2 (RRM2) found in the Hu proteins family, Drosophila sex-lethal (SXL), and similar proteins; This subfamily corresponds to the RRM2 of Hu proteins and SXL. The Hu proteins family represents a group of RNA-binding proteins involved in diverse biological processes. Since the Hu proteins share high homology with the Drosophila embryonic lethal abnormal vision (ELAV) protein, the Hu family is sometimes referred to as the ELAV family. Drosophila ELAV is exclusively expressed in neurons and is required for the correct differentiation and survival of neurons in flies. The neuronal members of the Hu family include Hu-antigen B (HuB or ELAV-2 or Hel-N1), Hu-antigen C (HuC or ELAV-3 or PLE21), and Hu-antigen D (HuD or ELAV-4), which play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. Hu-antigen R (HuR or ELAV-1 or HuA) is the ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. Hu proteins perform their cytoplasmic and nuclear molecular functions by coordinately regulating functionally related mRNAs. In the cytoplasm, Hu proteins recognize and bind to AU-rich RNA elements (AREs) in the 3' untranslated regions (UTRs) of certain target mRNAs, such as GAP-43, vascular epithelial growth factor (VEGF), the glucose transporter GLUT1, eotaxin and c-fos, and stabilize those ARE-containing mRNAs. They also bind and regulate the translation of some target mRNAs, such as neurofilament M, GLUT1, and p27. In the nucleus, Hu proteins function as regulators of polyadenylation and alternative splicing. Each Hu protein contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions. Also included in this subfamily is the sex-lethal protein (SXL) from Drosophila melanogaster. SXL governs sexual differentiation and X chromosome dosage compensation in flies. 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 RRMs that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

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gi 61966711  16 SRVFIGNLNTLVVKKsDVEAIFSKYGKIAG--------CSVHKGFAFVQYDKEKNARAAVAGEDGRMI--ASQVVDINLA 85
Cdd:cd12376   1 ANLYVSGLPKTMTQK-ELEQLFSQYGRIITsrilrdqlTGVSRGVGFIRFDKRIEAEEAIKGLNGQKPegASEPITVKFA 79

RNA recognition motif (RRM) found in the Aly/REF family; This subfamily corresponds to the RRM of Aly/REF family which includes THO complex subunit 4 (THOC4, also termed Aly/REF), S6K1 Aly/REF-like target (SKAR, also termed PDIP3 or PDIP46) and similar proteins. THOC4 is an mRNA transporter protein with a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It is involved in RNA transportation from the nucleus, and was initially identified as a transcription coactivator of LEF-1 and AML-1 for the TCRalpha enhancer function. In addition, THOC4 specifically binds to rhesus (RH) promoter in erythroid, and might be a novel transcription cofactor for erythroid-specific genes. SKAR shows high sequence homology with THOC4 and possesses one RRM as well. SKAR is widely expressed and localizes to the nucleus. It may be a critical player in the function of S6K1 in cell and organism growth control by binding the activated, hyperphosphorylated form of S6K1 but not S6K2. Furthermore, SKAR functions as a protein partner of the p50 subunit of DNA polymerase delta. In addition, SKAR may have particular importance in pancreatic beta cell size determination and insulin secretion.

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gi 61966711  16 SRVFIGNLNTLVVKKsDVEAIFSKYGKIAGCSVH-------KGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINL 84
Cdd:cd12418   1 TRVRVSNLHPDVTEE-DLRELFGRVGPVKSVKINydrsgrsTGTAYVVFERPEDAEKAIKQFDGVLLDGQPMKVEL 75

RNA recognition motif 1 (RRM1) found in heterogeneous nuclear ribonucleoprotein hnRNP A and hnRNP D subfamilies and similar proteins; This subfamily corresponds to the RRM1 in the hnRNP A subfamily which includes hnRNP A0, hnRNP A1, hnRNP A2/B1, hnRNP A3 and similar proteins. hnRNP A0 is a low abundance hnRNP protein that has been implicated in mRNA stability in mammalian cells. hnRNP A1 is an abundant eukaryotic nuclear RNA-binding protein that may modulate splice site selection in pre-mRNA splicing. hnRNP A2/B1 is an RNA trafficking response element-binding protein that interacts with the hnRNP A2 response element (A2RE). hnRNP A3 is also a RNA trafficking response element-binding protein that participates in the trafficking of A2RE-containing RNA. The hnRNP A subfamily is characterized by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a long glycine-rich region at the C-terminus. The hnRNP D subfamily includes hnRNP D0, hnRNP A/B, hnRNP DL and similar proteins. hnRNP D0 is 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. hnRNP A/B 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 members in this subfamily contain two putative RRMs and a glycine- and tyrosine-rich C-terminus. The family also contains DAZAP1 (Deleted in azoospermia-associated protein 1), RNA-binding protein Musashi homolog Musashi-1, Musashi-2 and similar proteins. They all harbor two RRMs.

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gi 61966711  37 FSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGE----DGRMI 75
Cdd:cd12325  19 FSKYGEVVDCVVmkdpatgrSRGFGFVTFKDPSSVDAVLAARphtlDGRTI 69

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.

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gi 61966711  16 SRVFIGNLNTLVVKKSdVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDGRMIASQVVDINLA 85
Cdd:cd12449   1 GKLFVGGLSFDTNEQS-LEEVFSKYGQISEVVVvkdretqrSRGFGFVTFENPDDAKDAMMAMNGKSLDGRQIRVDQA 77

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.

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gi 61966711  28 VKKSDVEAIFSKYGKIAGCSV--------HKGFAFVQYDKEKNARAAVAGEDG 72
Cdd:cd12651  14 ITEDELDTIFGAYGNIVQKNLlrdkltgrPRGVAFVRYDKREEAQAAISALNG 66