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 17538232 594 TIFVSNLDFTTTEDEIRQAIEGVASIRFARKANSDLVH-RGFAYVVMENDQKAQQALLKDRVPVKGRPMFIS 664
Cdd:cd12391   1 TVFVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKsKGYCYVEFKDEESAQKALKLDRQPVEGRPMFVS 72

Lsm interaction motif; This short motif is found at the C-terminus of Prp24 proteins and probably interacts with the Lsm proteins to promote U4/U6 formation.

                          10
                  ....*....|....*...
gi 17538232   818 TSTSQPLSNDQFRKMFMK 835
Cdd:pfam05391   2 ASTAKPKSNDDFRKMFLK 19

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 594 TIFVSNLDFTTTEDEIRQAIEGVASIRFARKANSDLVH-RGFAYVVMENDQKAQQALLKDRVPVKGRPMFIS 664
Cdd:cd12391   1 TVFVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKsKGYCYVEFKDEESAQKALKLDRQPVEGRPMFVS 72

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17538232    684 KVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDKEtGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLKV 73

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 17538232   685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELE 754
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRDETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17538232    594 TIFVSNLDFTTTEDEIRQAIE---GVASIRFARKANSDlVHRGFAYVVMENDQKAQQALLK-DRVPVKGRPMFI 663
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSkfgKVESVRLVRDKETG-KSKGFAFVEFESEEDAEKALEAlNGKELDGRPLKV 73

glycine-rich RNA-binding protein 4; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232  677 STTLEKSKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:PLN03134  29 SLRLMSTKLFIGGLSWGTDDASLRDAFAHFGDVVDAKVIVDREtGRSRGFGFVNFNDEGAATAAISEMDGKELNGRHIRV 108

                 ....
gi 17538232  756 ALSN 759
Cdd:PLN03134 109 NPAN 112

sex-lethal family splicing factor; This model describes the sex-lethal family of splicing factors found in Dipteran insects. The sex-lethal phenotype, however, may be limited to the Melanogasters and closely related species. In Drosophila the protein acts as an inhibitor of splicing. This subfamily is most closely related to the ELAV/HUD subfamily of splicing factors (TIGR01661).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17538232   695 TDDELKALFSKFGTVTSVRRV-THKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVALSNP 760
Cdd:TIGR01659 120 TDRELYALFRTIGPINTCRIMrDYKTGYSFGYAFVDFGSEADSQRAIKNLNGITVRNKRLKVSYARP 186

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 594 TIFVSNLDFTTTEDEIRQAIEGVASIRFARKANSDLVH-RGFAYVVMENDQKAQQALLKDRVPVKGRPMFIS 664
Cdd:cd12391   1 TVFVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKsKGYCYVEFKDEESAQKALKLDRQPVEGRPMFVS 72

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17538232    684 KVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDKEtGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLKV 73

RNA recognition motif 3 (RRM3) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM3 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        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDK------LMLRERELEVAL 757
Cdd:cd12415   3 VFIRNLSFDTTEEDLKEFFSKFGEVKYARIVLDKDtGHSKGTAFVQFKTKESADKCIEAANDesedggLVLDGRKLIVSL 82

RNA recognition motif (RRM) found in AZoospermia (DAZ) autosomal homologs, DAZL (DAZ-like) and BOULE; This subfamily corresponds to the RRM domain of two Deleted in AZoospermia (DAZ) autosomal homologs, DAZL (DAZ-like) and BOULE. BOULE is the founder member of the family and DAZL arose from BOULE in an ancestor of vertebrates. The DAZ gene subsequently originated from a duplication transposition of the DAZL gene. Invertebrates contain a single DAZ homolog, BOULE, while vertebrates, other than catarrhine primates, possess both BOULE and DAZL genes. The catarrhine primates possess BOULE, DAZL, and DAZ genes. The family members encode closely related RNA-binding proteins that are required for fertility in numerous organisms. These proteins contain an RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a varying number of copies of a DAZ motif, believed to mediate protein-protein interactions. DAZL and BOULE contain a single copy of the DAZ motif, while DAZ proteins can contain 8-24 copies of this repeat. Although their specific biochemical functions remain to be investigated, DAZL proteins may interact with poly(A)-binding proteins (PABPs), and act as translational activators of specific mRNAs during gametogenesis.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232 683 SKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVAlsnPPV 762
Cdd:cd12412   3 NRIFVGGIDWDTTEEELREFFSKFGKVKDVKIIKDRAGVSKGYGFVTFETQEDAEKIQKWGANLVFKGKKLNVG---PAI 79

                ..
gi 17538232 763 KK 764
Cdd:cd12412  80 RK 81

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 17538232   594 TIFVSNLDFTTTED---EIRQAIEGVASIRFARkansDLVHR---GFAYVVMENDQKAQQALLKDRV-PVKGRPMFI--S 664
Cdd:TIGR01628   2 SLYVGDLDPDVTEAklyDLFKPFGPVLSVRVCR----DSVTRrslGYGYVNFQNPADAERALETMNFkRLGGKPIRImwS 77

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232   665 ANDPEKR---VGfkfsttleksKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCVA 741
Cdd:TIGR01628  78 QRDPSLRrsgVG----------NIFVKNLDKSVDNKALFDTFSKFGNILSCKVATDENGKSRGYGFVHFEKEESAKAAIQ 147

                         170       180       190
                  ....*....|....*....|....*....|..
gi 17538232   742 SGDKLMLRERELEVAlsnPPVKKDKSHGKPAA 773
Cdd:TIGR01628 148 KVNGMLLNDKEVYVG---RFIKKHEREAAPLK 176

splicing factor, CC1-like family; This model represents a subfamily of RNA splicing factors including the Pad-1 protein (N. crassa), CAPER (M. musculus) and CC1.3 (H.sapiens). These proteins are characterized by an N-terminal arginine-rich, low complexity domain followed by three (or in the case of 4 H. sapiens paralogs, two) RNA recognition domains (rrm: pfam00706). These splicing factors are closely related to the U2AF splicing factor family (TIGR01642). A homologous gene from Plasmodium falciparum was identified in the course of the analysis of that genome at TIGR and was included in the seed.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232   574 TPAPGSFAVQKAAPGTEDARTIFVSNLDFTTTEDEIRQAIEGVASIRFAR--KANSDLVHRGFAYVVMENDQKAQQALLK 651
Cdd:TIGR01622  96 KPRARDGTPEPLTEDERDRRTVFVQQLAARARERDLYEFFSKVGKVRDVQiiKDRNSRRSKGVGYVEFYDVDSVQAALAL 175

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232   652 DRVPVKGRPMFISANDPEKRVGFKFSTTLEKS--------KVFVRNVHFQATDDELKALFSKFGTVTSVRrvTHKD---G 720
Cdd:TIGR01622 176 TGQKLLGIPVIVQLSEAEKNRAARAATETSGHhpnsipfhRLYVGNLHFNITEQDLRQIFEPFGEIEFVQ--LQKDpetG 253

                         170       180       190
                  ....*....|....*....|....*....|....*....
gi 17538232   721 KPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVALSN 759
Cdd:TIGR01622 254 RSKGYGFIQFRDAEQAKEALEKMNGFELAGRPIKVGLGN 292

RNA recognition motif 3 (RRM3) found in yeast nucleolar protein 4 (Nop4p) and similar proteins; This subgroup corresponds to the RRM3 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 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKL 746
Cdd:cd12676   4 LFVRNLPFDATEDELYSHFSQFGPLKYARVVKDPAtGRSKGTAFVKFKNKEDADNCLSAAPEA 66

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:cd12398   3 VFVGNIPYDATEEQLKEIFSEVGPVVSFRLVTDREtGKPKGYGFCEFRDAETALSAVRNLNGYELNGRPLRV 74

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
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCV 740
Cdd:cd12380   4 VYVKNFGEDVDDDELKELFEKYGKITSAKVMKDDSGKSKGFGFVNFENHEAAQKAV 59

RNA recognition motif 2 (RRM2) found in yeast nucleolar protein 13 (Nop13p) and similar proteins; This subfamily corresponds to the RRM2 of Nop13p encoded by YNL175c from Saccharomyces cerevisiae. It shares high sequence similarity with nucleolar protein 12 (Nop12p). Both Nop12p and Nop13p are not essential for growth. However, unlike Nop12p that is localized to the nucleolus, Nop13p localizes primarily to the nucleolus but is also present in the nucleoplasm to a lesser extent. Nop13p contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:cd12397   1 LFVGNLSFETTEEDLRKHFAPAGKIRKVRMATFEDsGKCKGFAFVDFKEIESATNAVKGPINHSLNGRDLRV 72

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        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17538232 684 KVFVRNVHFQATDDELKALFSKFGTVTSVR-RVTHKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVA 756
Cdd:cd12316   1 RLFVRNLPFTATEDELRELFEAFGKISEVHiPLDKQTKRSKGFAFVLFVIPEDAVKAYQELDGSIFQGRLLHVL 74

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 17538232    594 TIFVSNLDFTTTEDEIRQAIE---GVASIRFARKANSDlVHRGFAYVVMENDQKAQQALLK-DRVPVKGRPMFI 663
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSkfgKVESVRLVRDKETG-KSKGFAFVEFESEEDAEKALEAlNGKELDGRPLKV 73

RNA recognition motif 6 (RRM6) found in RNA-binding protein 19 (RBM19 or RBD-1) and RNA recognition motif 5 (RRM5) found in multiple RNA-binding domain-containing protein 1 (MRD1); This subfamily corresponds to the RRM6 of RBM19 and RRM5 of MRD1. RBM19, also termed RNA-binding domain-1 (RBD-1), is a nucleolar protein conserved in eukaryotes. It is 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
                ....*....|....*....|....*....|....*....|....*....|....*
gi 17538232 683 SKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQ 737
Cdd:cd12320   1 TKLIVKNVPFEATRKEIRELFSPFGQLKSVRLPKKFDGSHRGFAFVEFVTKQEAQ 55

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 17538232   595 IFVSNLDFTTTEDEIRQ--AIEGVASIRFARKANSDLVhRGFAYVVMENDQ---KAQQALLKDRVPVKGRPMFISANDPE 669
Cdd:TIGR01628 181 LYVKNLDPSVNEDKLRElfAKFGEITSAAVMKDGSGRS-RGFAFVNFEKHEdaaKAVEEMNGKKIGLAKEGKKLYVGRAQ 259

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232   670 KRVG------FKFST----TLEKSKV---FVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASA 736
Cdd:TIGR01628 260 KRAEreaelrRKFEElqqeRKMKAQGvnlYVKNLDDTVTDEKLRELFSECGEITSAKVMLDEKGVSRGFGFVCFSNPEEA 339

                         170       180
                  ....*....|....*....|..
gi 17538232   737 QKCVASGDKLMLRERELEVALS 758
Cdd:TIGR01628 340 NRAVTEMHGRMLGGKPLYVALA 361

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232 594 TIFVSNLDFTTTEDEIRQAIEG---VASI-----RFARKAnsdlvhRGFAYVVMENDQKAQQALLK-DRVPVKGRPMFIS 664
Cdd:COG0724   3 KIYVGNLPYSVTEEDLRELFSEygeVTSVklitdRETGRS------RGFGFVEMPDDEEAQAAIEAlNGAELMGRTLKVN 76

                ....*...
gi 17538232 665 -ANDPEKR 671
Cdd:COG0724  77 eARPREER 84

RNA recognition motif 2 (RRM2) found in RNA-binding protein 34 (RBM34) and similar proteins; This subfamily corresponds to the RRM2 of RBM34, a putative RNA-binding protein containing two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). Although the function of RBM34 remains unclear currently, its RRM domains may participate in mRNA processing. RBM34 may act as an mRNA processing-related protein.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDFDTEASAQKCVASGDKLmLRERELEV 755
Cdd:cd12395   2 VFVGNLPFDIEEEELRKHFEDCGDVEAVRIVRDREtGIGKGFGYVLFKDKDSVDLALKLNGSK-LRGRKLRV 72

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQK 738
Cdd:cd12391   2 VFVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKSKGYCYVEFKDEESAQK 55

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        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17538232 683 SKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVAL 757
Cdd:cd12381   2 VNLYVKNLDDTIDDEKLREEFSPFGTITSAKVMTDEGGRSKGFGFVCFSSPEEATKAVTEMNGRIIGGKPLYVAL 76

RNA recognition motif (RRM) found in Zinc finger CCHC-type and RNA-binding motif-containing protein 1 (ZCRB1) and similar proteins; This subfamily corresponds to the RRM of ZCRB1, also termed MADP-1, or U11/U12 small nuclear ribonucleoprotein 31 kDa protein (U11/U12 snRNP 31 or U11/U12-31K), a novel multi-functional nuclear factor, which may be involved in morphine dependence, cold/heat stress, and hepatocarcinoma. It is located in the nucleoplasm, but outside the nucleolus. ZCRB1 is one of the components of U11/U12 snRNPs that bind to U12-type pre-mRNAs and form a di-snRNP complex, simultaneously recognizing the 5' splice site and branchpoint sequence. ZCRB1 is characterized by an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a CCHC-type Zinc finger motif. In addition, it contains core nucleocapsid motifs, and Lys- and Glu-rich domains.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 17538232 682 KSKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDG-KPKGIAFVDFDTEASAQKCVASGDKLMLRERELEV 755
Cdd:cd12393   1 KSTVYVSNLPFSLTNNDLHQIFSKYGKVVKVTILKDKETrKSKGVAFVLFLDRESAHNAVRAMNNKELFGRTLKC 75

RNA recognition motif 2 (RRM2) found in yeast nuclear polyadenylated RNA-binding protein 4 (Hrp1p or Nab4p) and similar proteins; This subfamily corresponds to the RRM1 of Hrp1p and similar proteins. Hrp1p or Nab4p, also termed cleavage factor IB (CFIB), is a sequence-specific trans-acting factor that is essential for mRNA 3'-end formation in yeast Saccharomyces cerevisiae. It can be UV cross-linked to RNA and specifically recognizes the (UA)6 RNA element required for both, the cleavage and poly(A) addition steps. Moreover, Hrp1p can shuttle between the nucleus and the cytoplasm, and play an additional role in the export of mRNAs to the cytoplasm. Hrp1p also interacts with Rna15p and Rna14p, two components of CF1A. In addition, Hrp1p functions as a factor directly involved in modulating the activity of the nonsense-mediated mRNA decay (NMD) pathway; it binds specifically to a downstream sequence element (DSE)-containing RNA and interacts with Upf1p, a component of the surveillance complex, further triggering the NMD pathway. Hrp1p contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an arginine-glycine-rich region harboring repeats of the sequence RGGF/Y.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 17538232 684 KVFVRNVHFQATDDELKALFSKFGTVT-SVRRVTHKDGKPKGIAFVDFDTEASAQKCVASGdKLMLRERELEVALSNP 760
Cdd:cd12330   1 KIFVGGLAPDVTEEEFKEYFEQFGTVVdAVVMLDHDTGRSRGFGFVTFDSESAVEKVLSKG-FHELGGKKVEVKRATP 77

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
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 17538232 681 EKSKVFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKD-GKPKGIAFVDF-DTEASAQ 737
Cdd:cd12566   1 ETGRLFLRNLPYSTKEDDLQKLFSKFGEVSEVHVPIDKKtKKSKGFAYVLFlDPEDAVQ 59

RNA recognition motif in type II polyadenylate-binding proteins; This subfamily corresponds to the RRM of type II polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 2 (PABP-2 or PABPN1), embryonic polyadenylate-binding protein 2 (ePABP-2 or PABPN1L) and similar proteins. PABPs are 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. ePABP-2 is predominantly located in the cytoplasm and PABP-2 is located in the nucleus. In contrast to the type I PABPs containing four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), the type II PABPs contains a single highly-conserved RRM. This subfamily also includes Saccharomyces cerevisiae RBP29 (SGN1, YIR001C) gene encoding cytoplasmic mRNA-binding protein Rbp29 that binds preferentially to poly(A). Although not essential for cell viability, Rbp29 plays a role in modulating the expression of cytoplasmic mRNA. Like other type II PABPs, Rbp29 contains one RRM only.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHK-DGKPKGIAFVDFDTEASAQKCVASGDKlMLRERELEV 755
Cdd:cd12306   2 IYVGNVDYGTTPEELQAHFKSCGTINRVTILCDKfTGQPKGFAYIEFVDKSSVENALLLNES-EFRGRQIKV 72

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        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17538232 684 KVFVRNVHFQATDDELKALFSKFGTVTSV---RrvthkdgKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVALSNP 760
Cdd:cd12373   1 KVYVGNLGPRVTKRELEDAFEKYGPLRNVwvaR-------NPPGFAFVEFEDPRDAEDAVRALDGRRICGSRVRVELSRG 73

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        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFD-TEASAQKCVAS 742
Cdd:cd12226   2 LFVGGLSPSITEDDLERRFSRFGTVSDVEIIRKKDAPDRGFAYIDLRtSEAALQKCLST 60

RNA recognition motif 2 (RRM2) found in RNA-binding protein 34 (RBM34) and similar proteins; This subfamily corresponds to the RRM2 of RBM34, a putative RNA-binding protein containing two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). Although the function of RBM34 remains unclear currently, its RRM domains may participate in mRNA processing. RBM34 may act as an mRNA processing-related protein.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17538232 594 TIFVSNLDFTTTEDEIRQA------IEGVASIRfARKANsdlVHRGFAYVVMENDQKAQQALLKDRVPVKGRP 660
Cdd:cd12395   1 SVFVGNLPFDIEEEELRKHfedcgdVEAVRIVR-DRETG---IGKGFGYVLFKDKDSVDLALKLNGSKLRGRK 69

RNA recognition motif 1 (RRM1) found in Drosophila sex-lethal (SXL) and similar proteins; This subfamily corresponds to the RRM1 of 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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 17538232 695 TDDELKALFSKFGTVTSVRRVTHK-DGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVALSNPP 761
Cdd:cd12649  13 TDREFRALFRAIGPVNTCKIVRDKkTGYSYGFGFVDFTSEEDAQRAIKTLNGLQLQNKRLKVAYARPG 80

RNA recognition motif 1 in La autoantigen (La or LARP3) and similar proteins; This subfamily corresponds to the RRM1 of La autoantigen, also termed Lupus La protein, or La ribonucleoprotein, or Sjoegren syndrome type B antigen (SS-B), a highly abundant nuclear phosphoprotein and well conserved in eukaryotes. It specifically binds the 3'-terminal UUU-OH motif of nascent RNA polymerase III transcripts and protects them from exonucleolytic degradation by 3' exonucleases. In addition, La can directly facilitate the translation and/or metabolism of many UUU-3' OH-lacking cellular and viral mRNAs, through binding internal RNA sequences within the untranslated regions of target mRNAs. La contains an N-terminal La motif (LAM), followed by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). It also possesses a short basic motif (SBM) and a nuclear localization signal (NLS) at the C-terminus.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKP-KGIAFVDFDTEASAQKcVASGDKLMLRERELEV 755
Cdd:cd12291   2 VYVKGFPLDATLDDIQEFFEKKGKVENVRMRRDLDSKEfKGSVFVEFKTEEEAKK-FLEKEKLKYKGKELTI 72

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 17538232 685 VFVRNVHFQATDDELKALFSKFGTVTSVRRVTHKDGKPKGIAFVDFDTEASAQKCVASGDKLMLRERELEVA 756
Cdd:cd12379   5 IFIKNLDKSIDNKALYDTFSAFGNILSCKVATDENGGSKGYGFVHFETEEAAERAIEKVNGMLLNGKKVFVG 76