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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  15 DPKSINSRVFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGEPK 94
Cdd:cd12603     1 DPRSMNSRVFIGNLNTLVVKKSDVEAIFSKYGKIVGCSVHKGFAFVQYVNERNARAAVAGEDGRMIAGQVLDINLAAEPK 80

                  ...
gi 1229385572  95 PYR 97
Cdd:cd12603    81 VNR 83

RNA recognition motif (RRM) found in vertebrate heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNP C1/C2); This subgroup corresponds to the RRM of heterogeneous nuclear ribonucleoprotein C (hnRNP) proteins C1 and C2, produced by a single coding sequence. They are the major constituents of the heterogeneous nuclear RNA (hnRNA) ribonucleoprotein (hnRNP) complex in vertebrates. They bind hnRNA tightly, suggesting a central role in the formation of the ubiquitous hnRNP complex. They are involved in the packaging of hnRNA in the nucleus and in processing of pre-mRNA such as splicing and 3'-end formation. hnRNP C proteins contain 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 the variable region, the basic region and the KSG box rich in repeated Lys-Ser-Gly sequences, the leucine zipper, and the acidic region. The RRM is capable of binding poly(U). The KSG box may bind to RNA. The leucine zipper may be involved in dimer formation. The acidic and hydrophilic C-teminus harbors a putative nucleoside triphosphate (NTP)-binding fold and a protein kinase phosphorylation site.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  15 DPKSINSRVFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGEPK 94
Cdd:cd12603     1 DPRSMNSRVFIGNLNTLVVKKSDVEAIFSKYGKIVGCSVHKGFAFVQYVNERNARAAVAGEDGRMIAGQVLDINLAAEPK 80

                  ...
gi 1229385572  95 PYR 97
Cdd:cd12603    81 VNR 83

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 1229385572  23 VFIGNLNTAIVKKvDIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:pfam00076   1 LFVGNLPPDTTEE-DLKDLFSKFGPIKSIRLvrdetgrSKGFAFVEFEDEEDAEKAIEALNGKELGGREL 69

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1229385572  15 DP---KSINSRVFIGNLNTAIVKKVdIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIA 81
Cdd:TIGR01628  80 DPslrRSGVGNIFVKNLDKSVDNKA-LFDTFSKFGNILSCKVatdengkSRGYGFVHFEKEESAKAAIQKVNGMLLN 155

Predicted nucleic acid-binding protein DR0291, contains C4-type Zn-ribbon domain [General function prediction only];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572 195 ELQTIKKELTQIKTKIDSLLGRLEKIEKQQkAEAEAQKKQLEESLVLIQEECVSEIADHSTEEPAEggpDADGEEMTDGI 274
Cdd:COG1579    97 EIESLKRRISDLEDEILELMERIEELEEEL-AELEAELAELEAELEEKKAELDEELAELEAELEEL---EAEREELAAKI 172

                  ...
gi 1229385572 275 EED 277
Cdd:COG1579   173 PPE 175

RNA recognition motif (RRM) found in vertebrate heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNP C1/C2); This subgroup corresponds to the RRM of heterogeneous nuclear ribonucleoprotein C (hnRNP) proteins C1 and C2, produced by a single coding sequence. They are the major constituents of the heterogeneous nuclear RNA (hnRNA) ribonucleoprotein (hnRNP) complex in vertebrates. They bind hnRNA tightly, suggesting a central role in the formation of the ubiquitous hnRNP complex. They are involved in the packaging of hnRNA in the nucleus and in processing of pre-mRNA such as splicing and 3'-end formation. hnRNP C proteins contain 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 the variable region, the basic region and the KSG box rich in repeated Lys-Ser-Gly sequences, the leucine zipper, and the acidic region. The RRM is capable of binding poly(U). The KSG box may bind to RNA. The leucine zipper may be involved in dimer formation. The acidic and hydrophilic C-teminus harbors a putative nucleoside triphosphate (NTP)-binding fold and a protein kinase phosphorylation site.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  15 DPKSINSRVFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGEPK 94
Cdd:cd12603     1 DPRSMNSRVFIGNLNTLVVKKSDVEAIFSKYGKIVGCSVHKGFAFVQYVNERNARAAVAGEDGRMIAGQVLDINLAAEPK 80

                  ...
gi 1229385572  95 PYR 97
Cdd:cd12603    81 VNR 83

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 1229385572  20 NSRVFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDIN 88
Cdd:cd12605     1 NSRVFIGNLNTAIVKKADIEAIFAKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARIIAGQPLDIN 69

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 1229385572  23 VFIGNLNTAiVKKVDIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDIN 88
Cdd:cd00590     1 LFVGNLPPD-TTEEDLRELFSKFGEVVSVRIvrdrdgkSKGFAFVEFESPEDAEKALEALNGTELGGRPLKVS 72

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 1229385572  23 VFIGNLNTAIVKKvDIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:pfam00076   1 LFVGNLPPDTTEE-DLKDLFSKFGPIKSIRLvrdetgrSKGFAFVEFEDEEDAEKAIEALNGKELGGREL 69

RNA recognition motif (RRM) found in yeast nuclear polyadenylated RNA-binding protein 3 (Nab3p) and similar proteins; This subfamily corresponds to the RRM of Nab3p, an acidic nuclear polyadenylated RNA-binding protein encoded by Saccharomyces cerevisiae NAB3 gene that is essential for cell viability. Nab3p is predominantly localized within the nucleoplasm and essential for growth in yeast. It may play an important role in packaging pre-mRNAs into ribonucleoprotein structures amenable to efficient nuclear RNA processing. Nab3p contains an N-terminal aspartic/glutamic acid-rich region, a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal region rich in glutamine and proline residues.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1229385572  22 RVFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12342     1 RLFIGNLPTKRVSKEDLFRIFSPYGHLMQIVIKNAFGFVQFDSPQSCRNAIECEQGEMNRGKKL 64

RNA recognition motif 1 (RRM1) and 2 (RRM2) found in RRM-containing coactivator activator/modulator (CoAA) and similar proteins; This subfamily corresponds to the RRM in CoAA (also known as RBM14 or PSP2) and RNA-binding protein 4 (RBM4). CoAA is 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. RBM4 is a ubiquitously expressed splicing factor with two isoforms, RBM4A (also known as Lark homolog) and RBM4B (also known as RBM30), which are very similar in structure and sequence. RBM4 may also function as a translational regulator of stress-associated mRNAs as well as play a role in micro-RNA-mediated gene regulation. RBM4 contains two N-terminal RRMs, a CCHC-type zinc finger, and three alanine-rich regions within their C-terminal regions. This family also includes Drosophila RNA-binding protein lark (Dlark), a homolog of human RBM4. It plays an important role in embryonic development and in the circadian regulation of adult eclosion. Dlark shares high sequence similarity with RBM4 at the N-terminal region. However, Dlark has three proline-rich segments instead of three alanine-rich segments within the C-terminal region.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1229385572  22 RVFIGNLNTAiVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12343     1 KIFVGNLPDA-ATSEELRALFEKYGKVTECDIVKNYAFVHMEKEEDAEDAIKALNGYEFMGSRI 63

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 1229385572  22 RVFIGNLnTAIVKKVDIEAIFSKYGKIVGCSVHK---GYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12373     1 KVYVGNL-GPRVTKRELEDAFEKYGPLRNVWVARnppGFAFVEFEDPRDAEDAVRALDGRRICGSRVRVELS 71

RNA recognition motif 2 (RRM2) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM2 of RBM28 and Nop4p. RBM28 is a specific nucleolar component of the spliceosomal small nuclear ribonucleoproteins (snRNPs), possibly coordinating their transition through the nucleolus. It specifically associates with U1, U2, U4, U5, and U6 small nuclear RNAs (snRNAs), and may play a role in the maturation of both small nuclear and ribosomal RNAs. RBM28 has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an extremely acidic region between RRM2 and RRM3. The family also includes nucleolar protein 4 (Nop4p or Nop77p) encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p also contains four RRMs.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  22 RVFIGNLnTAIVKKVDIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIAGQP 84
Cdd:cd12414     1 RLIVRNL-PFKCTEDDLKKLFSKFGKVLEVTIpkkpdgkLRGFAFVQFTNVADAAKAIKGMNGKKIKGRP 69

RNA recognition motif 2 (RRM2) found in (U)-binding-splicing factor PUF60 and similar proteins; This subfamily corresponds to the RRM2 of PUF60, also termed FUSE-binding protein-interacting repressor (FBP-interacting repressor or FIR), or Ro-binding protein 1 (RoBP1), or Siah-binding protein 1 (Siah-BP1). PUF60 is an essential splicing factor that functions as a poly-U RNA-binding protein required to reconstitute splicing in depleted nuclear extracts. Its function is enhanced through interaction with U2 auxiliary factor U2AF65. PUF60 also controls human c-myc gene expression by binding and inhibiting the transcription factor far upstream sequence element (FUSE)-binding-protein (FBP), an activator of c-myc promoters. PUF60 contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors another RRM and binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) in several nuclear proteins. Research indicates that PUF60 binds FUSE as a dimer, and only the first two RRM domains participate in the single-stranded DNA recognition.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1229385572  37 DIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12371    16 DIKSVFEAFGKIKSCSLapdpetgkHKGYGFIEYENPQSAQDAIASMNLFDLGGQYLRVGRA 77

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1229385572  15 DPKSInsrvFIGNLNTAIVKKvDIEAIFSKYGKIVGCS-VHK-----GYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12454     2 DKLSI----FVGQLDPKTTDS-ELFRRFSKYGKIVDCKlIKRpepvnAFAFLRFESEEAAEAAVEEENHSEFLNKQI 73

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 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSVH-----KGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12599     1 RVYVGNLPMDIRER-EVEDLFSKYGPVVSIDLKipprpPAYAFVEFEDARDAEDAIRGRDGYDFDGHRL 68

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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKI---------VGCSVHK--GYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12355     1 RLWIGNLDPRLTEY-HLLKLLSKYGKIkkfdflfhkTGPLKGQprGYCFVTFETKEEAEKAIECLNGKLALGKKLVVRWA 79

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

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1229385572  23 VFIGNLNTAIVKKvDIEAIFSKYGKIVGCSVH--KGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12354     3 VYVGNITKGLTEA-LLQQTFSPFGQILEVRVFpdKGYAFIRFDSHEAATHAIVSVNGTIINGQAV 66

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 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12596     3 RVYIGRLSYHVREK-DIQRFFSGYGKLLEVDLKNGYGFVEFEDSRDADDAVYELNGKELCGERVIVEHA 70

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 1229385572  23 VFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12233     2 LFVVGFDPGTTREEDIEKLFEPFGPLVRCDIRKTFAFVEFEDSEDATKALEALHGSRIDGSVLTVEFV 69

RNA recognition motif 2 (RRM2) found in chloroplastic plastid-specific 30S ribosomal protein 2 (PSRP-2) and similar proteins; PSRP-2, also called chloroplastic 30S ribosomal protein 2, or chloroplastic small ribosomal subunit protein cS22, is a component of the chloroplast ribosome (chloro-ribosome), a dedicated translation machinery responsible for the synthesis of chloroplast genome-encoded proteins, including proteins of the transcription and translation machinery and components of the photosynthetic apparatus. It binds single strand DNA (ssDNA) and RNA in vitro. It exhibits RNA chaperone activity and regulates negatively resistance responses to abiotic stresses during seed germination (e.g. salt, dehydration, and low temperature) and seedling growth (e.g. salt). PSRP-2 contains 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 1229385572  22 RVFIGNLNTAIVKKVdIEAIFSKYGKIVGCSVHK--------GYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd21610     4 KVYVGNLAKTVTNEL-LKDFFSEKGKVLGAKVQRtpgtsksnGFGFVSFSSEEDVEAAIQALNNSVLEGQKIRVNKA 79

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1229385572  23 VFIGNLNTAIVKKvDIEAIFSKYGKIVGCSVH--------KGYAFVQYMSERHARAAVAGENARVIAGQPLDIN 88
Cdd:cd12448     1 LFVGNLPFSATQD-ALYEAFSQHGSIVSVRLPtdretgqpKGFGYVDFSTIDSAEAAIDALGGEYIDGRPIRLD 73

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
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAV 72
Cdd:cd12595     1 RVFIGRLNPAAREK-DVERFFKGYGRIRDIDLKRGFGFVEFEDPRDADDAV 50

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1229385572  23 VFIGNLNTAIVKKVdIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12447     2 LFVGGLSWNVDDPW-LKKEFEKYGGVISARVitdrgsgrSKGYGYVDFATPEAAQKALAAMSGKEIDGRQINVDFS 76

RNA recognition motif 1 (RRM1) found in nucleolysin TIA-1 isoform p40 (p40-TIA-1) and similar proteins; This subgroup corresponds to the RRM1 of TIA-1, the 40-kDa isoform of T-cell-restricted intracellular antigen-1 (TIA-1) and a cytotoxic granule-associated RNA-binding protein mainly found in the granules of cytotoxic lymphocytes. TIA-1 can be phosphorylated by a serine/threonine kinase that is activated during Fas-mediated apoptosis, and functions as the granule component responsible for inducing apoptosis in cytolytic lymphocyte (CTL) targets. It is composed of three N-terminal highly homologous RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a glutamine-rich C-terminal auxiliary domain containing a lysosome-targeting motif. TIA-1 interacts with RNAs containing short stretches of uridylates and its RRM2 can mediate the specific binding to uridylate-rich RNAs.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1229385572  23 VFIGNLNTAIVKKVdIEAIFSKYGKIVGCSV------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12615     2 LYVGNLSRDVTEAL-ILQLFSQIGPCKNCKMimdtagNDPYCFVEFHEHRHAAAALAAMNGRKIMGKEVKVNWA 74

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 1229385572  21 SRVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12393     2 STVYVSNLPFSLTNN-DLHQIFSKYGKVVKVTIlkdketrkSKGVAFVLFLDRESAHNAVRAMNNKELFGRTL 73

RNA recognition motif 1 (RRM1) found in vertebrate serine/arginine-rich splicing factor 4 (SRSF4); This subgroup corresponds to the RRM1 of SRSF4, also termed pre-mRNA-splicing factor SRp75, or SRP001LB, or splicing factor, arginine/serine-rich 4 (SFRS4). SRSF4 is a splicing regulatory serine/arginine (SR) protein that plays an important role in both constitutive splicing and alternative splicing of many pre-mRNAs. For instance, it interacts with heterogeneous nuclear ribonucleoproteins, hnRNP G and hnRNP E2, and further regulates the 5' splice site of tau exon 10, whose misregulation causes frontotemporal dementia. SFSF4 also induces production of HIV-1 vpr mRNA through the inhibition of the 5'-splice site of exon 3. In addition, it activates splicing of the cardiac troponin T (cTNT) alternative exon by direct interactions with the cTNT exon 5 enhancer RNA. SRSF4 can shuttle between the nucleus and cytoplasm. It contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a glycine-rich region, an internal region homologous to the RRM, and a very long, highly phosphorylated C-terminal SR domains rich in serine-arginine dipeptides.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1229385572  21 SRVFIGNLNTAiVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGEPK 94
Cdd:cd12594     2 PRVYIGRLSYQ-ARERDVERFFKGYGKILEVDLKNGYGFVEFDDLRDADDAVYELNGKDLCGERVIVEHARGPR 74

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 1229385572  22 RVFIGNLNTAiVKKVDIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd21608     1 KLYVGNLSWD-TTEDDLRDLFSEFGEVESAKVitdretgrSRGFGFVTFSTAEAAEAAIDALNGKELDGRSIVVNEA 76

RNA recognition motif (RRM) found in Arabidopsis thaliana arginine/serine-rich-splicing factor RSp31 and similar proteins from plants; This subfamily corresponds to the RRM1in a family that represents 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 RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), at their N-terminus, and an RS domain at their C-terminus.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1229385572  23 VFIGNLNTAiVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAVAG 74
Cdd:cd12234     3 VFCGNFEYD-ARQSEIERLFGKYGRVDRVDMKSGYAFVYMEDERDAEDAIRG 53

RNA recognition motif (RRM) found in ist3 family; This subfamily corresponds to the RRM of the ist3 family that includes fungal U2 small nuclear ribonucleoprotein (snRNP) component increased sodium tolerance protein 3 (ist3), X-linked 2 RNA-binding motif proteins (RBMX2) found in Metazoa and plants, and similar proteins. Gene IST3 encoding ist3, also termed U2 snRNP protein SNU17 (Snu17p), is a novel yeast Saccharomyces cerevisiae protein required for the first catalytic step of splicing and for progression of spliceosome assembly. It binds specifically to the U2 snRNP and is an intrinsic component of prespliceosomes and spliceosomes. Yeast ist3 contains an atypical RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). In the yeast pre-mRNA retention and splicing complex, the atypical RRM of ist3 functions as a scaffold that organizes the other two constituents, Bud13p (bud site selection 13) and Pml1p (pre-mRNA leakage 1). Fission yeast Schizosaccharomyces pombe gene cwf29 encoding ist3, also termed cell cycle control protein cwf29, is an RNA-binding protein complexed with cdc5 protein 29. It also contains one RRM. The biological function of RBMX2 remains unclear. It shows high sequence similarity to yeast ist3 protein and harbors one RRM as well.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1229385572  23 VFIGNLNTAIVKKvDIEAIFSKYGKIV--------GCSVHKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd12411    12 IYIGGLPYELTEG-DILCVFSQYGEIVdinlvrdkKTGKSKGFAFLAYEDQRSTILAVDNLNGIKLLGRTI 81

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 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKI--VGCSVHKG---YAFVQYMSERHARAAVAGEN 76
Cdd:cd12598     1 RIYVGNLPSDVREK-DLEDLFYKYGRIrdIELKNRRGlvpFAFVRFEDPRDAEDAVFGRN 59

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  21 SRVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGE 92
Cdd:cd12449     1 GKLFVGGLSFDTNEQ-SLEEVFSKYGQISEVVVvkdretqrSRGFGFVTFENPDDAKDAMMAMNGKSLDGRQIRVDQAGK 79

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1229385572  20 NSRVFIGNLNTAIVKKVdIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMA 90
Cdd:cd12381     1 GVNLYVKNLDDTIDDEK-LREEFSPFGTITSAKVmtdeggrSKGFGFVCFSSPEEATKAVTEMNGRIIGGKPLYVALA 77

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1229385572  15 DPKSinsrVFIGNLNTAIV-KKVDIEAIFSKYGKIVGC--------SVHKGYAFVQYMSERHARAAVAGENARVIAGQPL 85
Cdd:cd21622     2 DPCN----LFVKNLDDTVItNKEDLEQLFSPFGQIVSSylatypgtGISKGFGFVAFSKPEDAAKAKETLNGVMVGRKRI 77

                          90
                  ....*....|....
gi 1229385572  86 DINMAgEPKPYRPK 99
Cdd:cd21622    78 FVSYA-ERKEDREK 90

RNA recognition motif (RRM) found in S6K1 Aly/REF-like target (SKAR) and similar proteins; This subgroup corresponds to the RRM of SKAR, also termed polymerase delta-interacting protein 3 (PDIP3), 46 kDa DNA polymerase delta interaction protein (PDIP46), belonging to the Aly/REF family of RNA binding proteins that have been implicated in coupling transcription with pre-mRNA splicing and nucleo-cytoplasmic mRNA transport. 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. SKAR contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1229385572  22 RVFIGNLNTaIVKKVDIEAIFSKYGKIVGCSVHK-GYAFVQYMSERHARAAVAGENARVIAGQPLDINM 89
Cdd:cd12681     2 RLTVSNLHP-SVTEDDIVELFSVIGALKRARLVRpGVAEVVYVRREDAITAIKKYNNRELDGQPMKCKL 69

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

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1229385572  24 FIGNLnTAIVKKVDIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQ 83
Cdd:cd12417     3 WISGL-SDTTKAADLKKIFSKYGKVVSAKVvtsartpgSRCYGYVTMASVEEADLCIKSLNKTELHGR 69

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
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1229385572  23 VFIGNLnTAIVKKVDIEAIFSKYGKIV--------GCSVHKGYAFVQYmsERHARAAVA 73
Cdd:cd12365     1 LHVGKL-TRNVTKDHLKEIFSVYGTVKnvdlpidrEPNLPRGYAYVEF--ESPEDAEKA 56

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1229385572  21 SRVFIGNLNTAiVKKVDIEAIFSKYGKIvgCSVH----------KGYAFVQYMSERHARAAVAGENARVIAGQPLDI 87
Cdd:cd12566     3 GRLFLRNLPYS-TKEDDLQKLFSKFGEV--SEVHvpidkktkksKGFAYVLFLDPEDAVQAYNELDGKVFQGRLIHI 76

RNA recognition motif 2 (RRM2) found in Arabidopsis thaliana arginine/serine-rich-splicing factor RSp31 and similar proteins from plants; This subgroup corresponds to the RRM2 in a family that represents 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 RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), at their N-terminus, and an RS domain at their C-terminus.

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gi 1229385572  23 VFIGNLNTAIVKKVDIEAIFSKYGKIVGCSVHKGYAFVQYMSERHARAAV 72
Cdd:cd12466     2 LFVINFDPIRTKERDLERHFEPYGKVVNVRIRRNFAFVQYETQEDATKAL 51

RNA recognition motif 1 (RRM1) found in nucleolysin TIAR and similar proteins; This subgroup corresponds to the RRM1 of nucleolysin TIAR, also termed TIA-1-related protein, and a cytotoxic granule-associated RNA-binding protein that shows high sequence similarity with 40-kDa isoform of T-cell-restricted intracellular antigen-1 (p40-TIA-1). TIAR is mainly localized in the nucleus of hematopoietic and nonhematopoietic cells. It is translocated from the nucleus to the cytoplasm in response to exogenous triggers of apoptosis. TIAR possesses nucleolytic activity against cytolytic lymphocyte (CTL) target cells. It can trigger DNA fragmentation in permeabilized thymocytes, and thus may function as an effector responsible for inducing apoptosis. TIAR is composed of three N-terminal highly homologous RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a glutamine-rich C-terminal auxiliary domain containing a lysosome-targeting motif. It interacts with RNAs containing short stretches of uridylates and its RRM2 can mediate the specific binding to uridylate-rich RNAs.

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gi 1229385572  23 VFIGNLNTAIVKKVdIEAIFSKYGKIVGC------SVHKGYAFVQYMSERHARAAVAGENARVIAGQPLDINMAGEP 93
Cdd:cd12616     2 LYVGNLSRDVTEVL-ILQLFSQIGPCKSCkmitehTSNDPYCFVEFYEHRDAAAALAAMNGRKILGKEVKVNWATTP 77

RNA recognition motif 2 (RRM2) found in CUGBP Elav-like family member CELF-3, CELF-4, CELF-5, CELF-6 and similar proteins; This subgroup corresponds to the RRM2 of CELF-3, CELF-4, CELF-5, and CELF-6, all of which belong to the CUGBP1 and ETR-3-like factors (CELF) or BRUNOL (Bruno-like) family of RNA-binding proteins that display dual nuclear and cytoplasmic localizations and have been implicated in the regulation of pre-mRNA splicing and in the control of mRNA translation and deadenylation. CELF-3, expressed in brain and testis only, is also known as bruno-like protein 1 (BRUNOL-1), or CAG repeat protein 4, or CUG-BP- and ETR-3-like factor 3, or embryonic lethal abnormal vision (ELAV)-type RNA-binding protein 1 (ETR-1), or expanded repeat domain protein CAG/CTG 4, or trinucleotide repeat-containing gene 4 protein (TNRC4). It plays an important role in the pathogenesis of tauopathies. CELF-3 contains three highly conserved RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains): two consecutive RRMs (RRM1 and RRM2) situated in the N-terminal region followed by a linker region and the third RRM (RRM3) close to the C-terminus of the protein. The effect of CELF-3 on tau splicing is mediated mainly by the RNA-binding activity of RRM2. The divergent linker region might mediate the interaction of CELF-3 with other proteins regulating its activity or involved in target recognition. CELF-4, being highly expressed throughout the brain and in glandular tissues, moderately expressed in heart, skeletal muscle, and liver, is also known as bruno-like protein 4 (BRUNOL-4), or CUG-BP- and ETR-3-like factor 4. Like CELF-3, CELF-4 also contain three highly conserved RRMs. The splicing activation or repression activity of CELF-4 on some specific substrates is mediated by its RRM1/RRM2. On the other hand, both RRM1 and RRM2 of CELF-4 can activate cardiac troponin T (cTNT) exon 5 inclusion. CELF-5, expressed in brain, is also known as bruno-like protein 5 (BRUNOL-5), or CUG-BP- and ETR-3-like factor 5. Although its biological role remains unclear, CELF-5 shares same domain architecture with CELF-3. CELF-6, being strongly expressed in kidney, brain, and testis, is also known as bruno-like protein 6 (BRUNOL-6), or CUG-BP- and ETR-3-like factor 6. It activates exon inclusion of a cardiac troponin T minigene in transient transfection assays in a muscle-specific splicing enhancer (MSE)-dependent manner and can activate inclusion via multiple copies of a single element, MSE2. CELF-6 also promotes skipping of exon 11 of insulin receptor, a known target of CELF activity that is expressed in kidney. In addition to three highly conserved RRMs, CELF-6 also possesses numerous potential phosphorylation sites, a potential nuclear localization signal (NLS) at the C terminus, and an alanine-rich region within the divergent linker region.

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gi 1229385572  22 RVFIGNLNTAIVKKvDIEAIFSKYGKIVGCSV-------HKGYAFVQYMSERHARAAVAG 74
Cdd:cd12635     3 KLFVGMLGKQQSED-DVRRLFEPFGSIEECTIlrgpdgnSKGCAFVKFSSHAEAQAAINA 61

poly-U binding splicing factor, half-pint family; The proteins represented by this model contain three RNA recognition motifs (rrm: pfam00076) and have been characterized as poly-pyrimidine tract binding proteins associated with RNA splicing factors. In the case of PUF60 (GP|6176532), in complex with p54, and in the presence of U2AF, facilitates association of U2 snRNP with pre-mRNA.

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gi 1229385572  15 DPKSINsRVFIGNLNTAIvKKVDIEAIFSKYGKIVGCSV--------HKGYAFVQYMSERHARAAVAGENARVIAGQPLD 86
Cdd:TIGR01645 200 EAKKFN-RIYVASVHPDL-SETDIKSVFEAFGEIVKCQLaraptgrgHKGYGFIEYNNLQSQSEAIASMNLFDLGGQYLR 277