Forty-two-three protein; This family consists of several mammalian proteins of around 320 residues in length called 40-2-3 proteins. The function of this family is unknown.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 262263334    6 DKMDMSLEDIIKLNKMQQGRRDRP--DSRVKR-GTGPKRYRPAF------THGGRNRLAPycRPKQLPDK 66
Cdd:pfam07078  20 DKIDMSLDDIIKLNRKEGRKQNFPslNRRIQQsRARQFRMRVIRwgtqqgKGFGKNRLGR--RGRKTPGK 87

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRC-GRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:COG0724    3 KIYVGNLPYSVTEEDLRELFSEYGEVTSVKLITDREtGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKV 75

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

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 262263334   88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPM 156
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRDETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGREL 69

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 262263334   87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYD-RCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHLVTSQI 165
Cdd:TIGR01622 216 RLYVGNLHFNITEQDLRQIFEPFGEIEFVQLQKDpETGRSKGYGFIQFRDAEQAKEALEKMNGFELAGRPIKVGLGNDFT 295

                          90
                  ....*....|
gi 262263334  166 DRQGRPALNS 175
Cdd:TIGR01622 296 PESDANLAQR 305

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12418    2 RVRVSNLHPDVTEEDLRELFGRVGPVKSVKINYDRSGRSTGTAYVVFERPEDAEKAIKQFDGVLLDGQPMKVEL 75

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRC-GRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:COG0724    3 KIYVGNLPYSVTEEDLRELFSEYGEVTSVKLITDREtGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKV 75

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).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVhydrcgRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12681    2 RLTVSNLHPSVTEDDIVELFSVIGALKRARL------VRPGVAEVVYVRREDAITAIKKYNNRELDGQPMKCKL 69

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 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd21608    1 KLYVGNLSWDTTEDDLRDLFSEFGEVESAKVITDReTGRSRGFGFVTFSTAEAAEAAIDALNGKELDGRSIVV 73

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRP 155
Cdd:cd12414    1 RLIVRNLPFKCTEDDLKKLFSKFGKVLEVTIPKKPDGKLRGFAFVQFTNVADAAKAIKGMNGKKIKGRP 69

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 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd12447    1 TLFVGGLSWNVDDPWLKKEFEKYGGVISARVITDRgSGRSKGYGYVDFATPEAAQKALAAMSGKEIDGRQINV 73

RNA recognition motif (RRM) found in yeast RNA annealing protein YRA1 (Yra1p), yeast mRNA export protein mlo3 and similar proteins; This subfamily corresponds to the RRM of Yra1p and mlo3. Yra1p is an essential nuclear RNA-binding protein encoded by Saccharomyces cerevisiae YRA1 gene. It belongs to the evolutionarily conserved REF (RNA and export factor binding proteins) family of hnRNP-like proteins. Yra1p possesses potent RNA annealing activity and interacts with a number of proteins involved in nuclear transport and RNA processing. It binds to the mRNA export factor Mex67p/TAP and couples transcription to export in yeast. Yra1p is associated with Pse1p and Kap123p, two members of the beta-importin family, further mediating transport of Yra1p into the nucleus. In addition, the co-transcriptional loading of Yra1p is required for autoregulation. Yra1p consists of two highly conserved N- and C-terminal boxes and a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). This subfamily includes RNA-annealing protein mlo3, also termed mRNA export protein mlo3, which has been identified in fission yeast as a protein that causes defects in chromosome segregation when overexpressed. It shows high sequence similarity with Yra1p.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 262263334  87 KLFLSNLHFGVSDADIQLLFA-EFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDG-RPMNIHLV 161
Cdd:cd12267    2 KVIVSNLPKDVTEAQIREYFVsQIGPIKRVLLSYNEGGKSTGIANITFKRAGDATKAYDKFNGRLDDGnRKMKVEVV 78

RNA recognition motif 1 (RRM1) found in nucleolin-like proteins mainly from plants; This subfamily corresponds to the RRM1 of a group of plant nucleolin-like proteins, including nucleolin 1 (also termed protein nucleolin like 1) and nucleolin 2 (also termed protein nucleolin like 2, or protein parallel like 1). They play roles in the regulation of ribosome synthesis and in the growth and development of plants. Like yeast nucleolin, nucleolin-like proteins possess two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMrEYNGAPLDGR 154
Cdd:cd12450    2 LFVGNLSWSATQDDLENFFSDCGEVVDVRIAMDRdDGRSKGFGHVEFASAESAQKAL-EKSGQDLGGR 68

RNA recognition motif 2 (RRM2) found in squamous cell carcinoma antigen recognized by T-cells 3 (SART3) and similar proteins; This subfamily corresponds to the RRM2 of SART3, also termed Tat-interacting protein of 110 kDa (Tip110), is 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGR 154
Cdd:cd12392    4 KLFVKGLPFSCTKEELEELFKQHGTVKDVRLVTYRNGKPKGLAYVEYENEADASQAVLKTDGTEIKDH 71

RNA recognition motif 2 (RRM2) found in vertebrate myelin expression factor 2 (MEF-2); This subgroup corresponds to the RRM2 of MEF-2, also termed MyEF-2 or MST156, a sequence-specific single-stranded DNA (ssDNA) binding protein that binds specifically to ssDNA derived from the proximal (MB1) element of the myelin basic protein (MBP) promoter and represses transcription of the MBP gene. MEF-2 contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which may be responsible for its ssDNA binding activity.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12660    3 IFVANLDFKVGWKKLKEVFSMAGTVKRADIKEDKDGKSRGMGTVTFEQAIEAVQAISMFNGQFLFDRPMHVKM 75

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 262263334  85 GGKLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12381    1 GVNLYVKNLDDTIDDEKLREEFSPFGTITSAKVMTDEGGRSKGFGFVCFSSPEEATKAVTEMNGRIIGGKPLYVAL 76

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd12412    4 RIFVGGIDWDTTEEELREFFSKFGKVKDVKIIKDRAGVSKGYGFVTFETQEDAEKIQKWGANLVFKGKKLNV 75

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 262263334  86 GKLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd12382    2 GKLFIGGLNTETNEKALEAVFGKYGRIVEVLLMKDReTNKSRGFAFVTFESPADAKDAARDMNGKELDGKAIKV 75

RNA recognition motif 1 (RRM1) found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM1 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 mammals, 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 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 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYD---RcgRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd12378    2 LYVGDLHPDVTEAMLYEKFSPAGPVLSIRVCRDavtR--RSLGYAYVNFQQPADAERALDTLNFDVIKGKPIRI 73

RNA recognition motif 1 (RRM1) found in yeast regulator of rDNA transcription protein 5 (RRT5) and similar proteins; This subfamily corresponds to the RRM1 of the lineage specific family containing a group of uncharacterized yeast regulators of rDNA transcription protein 5 (RRT5), which may play roles in the modulation of rDNA transcription. RRT5 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTL----KKSAVHYDRCG--RSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12409    1 RVYISNLSYSTTEEELEELLKDYKPVsvliPSYTVRGFRSRkhRPLGIAYAEFSSVEEAEKVVKDLNGKVFKGRKLFVKL 80

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 262263334  89 FLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAM---REyngaPLDGRPM 156
Cdd:cd12391    3 FVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKSKGYCYVEFKDEESAQKALkldRQ----PVEGRPM 69

RNA recognition motif (RRM) found in vertebrate RNA binding protein fox-1 homologs and similar proteins; This subfamily corresponds to the RRM of several tissue-specific alternative splicing isoforms of vertebrate RNA binding protein Fox-1 homologs, which show high sequence similarity to the Caenorhabditis elegans feminizing locus on X (Fox-1) gene encoding Fox-1 protein. RNA binding protein Fox-1 homolog 1 (RBFOX1), also termed ataxin-2-binding protein 1 (A2BP1), or Fox-1 homolog A, or hexaribonucleotide-binding protein 1 (HRNBP1), is predominantly expressed in neurons, skeletal muscle and heart. It regulates alternative splicing of tissue-specific exons by binding to UGCAUG elements. Moreover, RBFOX1 binds to the C-terminus of ataxin-2 and forms an ataxin-2/A2BP1 complex involved in RNA processing. RNA binding protein fox-1 homolog 2 (RBFOX2), also termed Fox-1 homolog B, or hexaribonucleotide-binding protein 2 (HRNBP2), or RNA-binding motif protein 9 (RBM9), or repressor of tamoxifen transcriptional activity, is expressed in ovary, whole embryo, and human embryonic cell lines in addition to neurons and muscle. RBFOX2 activates splicing of neuron-specific exons through binding to downstream UGCAUG elements. RBFOX2 also functions as a repressor of tamoxifen activation of the estrogen receptor. RNA binding protein Fox-1 homolog 3 (RBFOX3 or NeuN or HRNBP3), also termed Fox-1 homolog C, is a nuclear RNA-binding protein that regulates alternative splicing of the RBFOX2 pre-mRNA, producing a message encoding a dominant negative form of the RBFOX2 protein. Its message is detected exclusively in post-mitotic regions of embryonic brain. Like RBFOX1, both RBFOX2 and RBFOX3 bind to the hexanucleotide UGCAUG elements and modulate brain and muscle-specific splicing of exon EIIIB of fibronectin, exon N1 of c-src, and calcitonin/CGRP. Members in this family also harbor one RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGrSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHLVT 162
Cdd:cd12407    2 RLHVSNIPFRFRDPDLRQMFGQFGTILDVEIIFNERG-SKGFGFVTFANSADADRAREKLNGTVVEGRKIEVNNAT 76

RNA recognition motif (RRM) found in transformer-2 protein homolog alpha (TRA-2 alpha) and similar proteins; This subgroup corresponds to the RRM of TRA2-alpha or TRA-2-alpha, also termed transformer-2 protein homolog A, a mammalian homolog of Drosophila transformer-2 (Tra2). TRA2-alpha is a 40-kDa serine/arginine-rich (SR) protein (SRp40) that specifically binds to gonadotropin-releasing hormone (GnRH) exonic splicing enhancer on exon 4 (ESE4) and is necessary for enhanced GnRH pre-mRNA splicing. It strongly stimulates GnRH intron A excision in a dose-dependent manner. In addition, TRA2-alpha can interact with either 9G8 or SRp30c, which may also be crucial for ESE-dependent GnRH pre-mRNA splicing. TRA2-alpha contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), flanked by the N- and C-terminal arginine/serine (RS)-rich regions.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 262263334  93 LHFGVSDADIQLLFAEFGTLKKSAVHYD-RCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd12642   12 LSLYTTERDLREVFSRYGPLAGVNVVYDqRTGRSRGFAFVYFERIDDSKEAMERANGMELDGRRIRV 78

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 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAP 150
Cdd:cd12676    4 LFVRNLPFDATEDELYSHFSQFGPLKYARVVKDPaTGRSKGTAFVKFKNKEDADNCLSAAPEAQ 67

RNA recognition motif 2 (RRM2) found in vertebrate heterogeneous nuclear ribonucleoprotein M (hnRNP M); This subgroup corresponds to the RRM2 of hnRNP M, a pre-mRNA binding protein that may play an important role in the pre-mRNA processing. It also preferentially binds to poly(G) and poly(U) RNA homopolymers. hnRNP M is able to interact with early spliceosomes, further influencing splicing patterns of specific pre-mRNAs. It functions as the receptor of carcinoembryonic antigen (CEA) that contains the penta-peptide sequence PELPK signaling motif. In addition, hnRNP M and another splicing factor Nova-1 work together as dopamine D2 receptor (D2R) pre-mRNA-binding proteins. They regulate alternative splicing of D2R pre-mRNA in an antagonistic manner. hnRNP M contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an unusual hexapeptide-repeat region rich in methionine and arginine residues (MR repeat motif).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12659    3 VFVANLDYKVGWKKLKEVFSMAGVVVRADILEDKDGKSRGIGTVTFEQPIEAVQAISMFNGQLLFDRPMHVKM 75

RNA recognition motif (RRM) found in pre-mRNA cleavage factor Im 68 kDa subunit (CFIm68 or CPSF6), pre-mRNA cleavage factor Im 59 kDa subunit (CFIm59 or CPSF7), and similar proteins; This subfamily corresponds to the RRM of cleavage factor Im (CFIm) subunits. Cleavage factor Im (CFIm) is a highly conserved component of the eukaryotic mRNA 3' processing machinery that functions in UGUA-mediated poly(A) site recognition, the regulation of alternative poly(A) site selection, mRNA export, and mRNA splicing. It is a complex composed of a small 25 kDa (CFIm25) subunit and a larger 59/68/72 kDa subunit. Two separate genes, CPSF6 and CPSF7, code for two isoforms of the large subunit, CFIm68 and CFIm59. Structurally related CFIm68 and CFIm59, also termed cleavage and polyadenylation specificity factor subunit 6 (CPSF7), or cleavage and polyadenylation specificity factor 59 kDa subunit (CPSF59), are functionally redundant. Both contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a central proline-rich region, and a C-terminal RS-like domain. Their N-terminal RRM mediates the interaction with CFIm25, and also serves to enhance RNA binding and facilitate RNA looping.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFG--TLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPM 156
Cdd:cd12372    1 LYVGNLQWWTTDEDLEGACASFGvvDVKEIKFFEHKaNGKSKGYAYVEFASPAAAAAVKEKLEKREFNGRPC 72

RNA recognition motif 3 (RRM3) found in vertebrate APOBEC-1 complementation factor (ACF); This subgroup corresponds to the RRM3 of ACF, also termed APOBEC-1-stimulating protein, an RNA-binding subunit of a core complex that interacts with apoB mRNA to facilitate C to U RNA editing. It may also act as an apoB mRNA recognition factor and chaperone and play a key role in cell growth and differentiation. ACF shuttles between the cytoplasm and nucleus. ACF contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which display high affinity for an 11 nucleotide AU-rich mooring sequence 3' of the edited cytidine in apoB mRNA. All three RRMs may be required for complementation of editing activity in living cells. RRM2/3 are implicated in ACF interaction with APOBEC-1.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  88 LFLSNLHFGVSDADIQllfAEFGTLKKSAVhyDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12498   11 LYVRNLMLSTTEETIE---KEFSNIKPGAV--ERVKKIRDYAFVHFYNREDAVNAMNALNGKVIDGSPIEVTL 78

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDrcgrslgTAHVHFERKADALKAMREYNGAPLDGRPMNIHL 160
Cdd:cd12251    4 LYVRNLMLSTTEEKLRELFSEYGKVERVKKIKD-------YAFVHFEERDDAVKAMEEMNGKELEGSEIEVSL 69

RNA recognition motif 1 (RRM1) 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). The family also includes Nicotiana sylvestris chloroplastic 33 kDa ribonucleoprotein (NsCP33) and Arabidopsis thaliana chloroplastic 31 kDa ribonucleoprotein (AtCP31A). 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. 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 first RRM motif.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd21609    1 RLYVGNIPRNVTSEELAKIFEEAGTVEIAEVMYDRyTGRSRGFGFVTMGSVEDAKAAIEKLNGTEVGGREIKV 73

RNA recognition motif 1 (RRM1) found in Saccharomyces cerevisiae protein PES4, protein MIP6 and similar proteins; The family includes PES4 (also called DNA polymerase epsilon suppressor 4) and MIP6 (also called MEX67-interacting protein 6), both of which are predicted RNA binding proteins that may act as regulators of late translation, protection, and mRNA localization. MIP6 acts as a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores. It interacts with MEX67. Members in this family contain four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the first RRM motif.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYD-RCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNI 158
Cdd:cd21601    3 LFIGDLDKDVTEEMLRDIFSKYKSLVSVKICLDsETKKSLGYGYLNFSDKEDAEKAIEEFNYTPIFGKEVRI 74

RNA recognition motif 1 (RRM1) found in Saccharomyces cerevisiae protein HRB1, G-strand-binding protein 2 (GBP2) and similar proteins; The family includes Saccharomyces cerevisiae protein HRB1 (also called protein TOM34) and GBP2, both of which are SR-like mRNA-binding proteins which shuttle from the nucleus to the cytoplasm when bound to the mature mRNA molecules. They act as quality control factors for spliced mRNAs. GBP2, also called RAP1 localization factor 6, is a single-strand telomeric DNA-binding protein that binds single-stranded telomeric sequences of the type (TG[1-3])n in vitro. It also binds to RNA. GBP2 influences the localization of RAP1 in the nuclei and plays a role in modulating telomere length. Members in this family contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the first RRM motif.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRcGRSLGTAHVHFERKADALKAMREYNGAPLDGR 154
Cdd:cd21605    4 IFVGNLPFDCTWEDLKDHFSQVGEVIRADIVTSR-GRHRGMGTVEFTNKEDVDRAISKFDHTMFMGR 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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 262263334   86 GKLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHLVTSQI 165
Cdd:TIGR01628  89 GNIFVKNLDKSVDNKALFDTFSKFGNILSCKVATDENGKSRGYGFVHFEKEESAKAAIQKVNGMLLNDKEVYVGRFIKKH 168

                  ....*..
gi 262263334  166 DRQGRPA 172
Cdd:TIGR01628 169 EREAAPL 175

RNA recognition motif 5 (RRM5) found in RNA-binding protein RBM12, RBM12B and similar proteins; This subfamily corresponds to the RRM5 of RBM12 and RBM12B. RBM12, also termed SH3/WW domain anchor protein in the nucleus (SWAN), is ubiquitously expressed. It contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two proline-rich regions, and several putative transmembrane domains. RBM12B show high sequence semilarity with RBM12. It contains five distinct RRMs as well. The biological roles of both RBM12 and RBM12B remain unclear.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 262263334  90 LSNLHFGVSDADIQLLFAEFGTLKKSA-VHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRpmNIHL 160
Cdd:cd12515    5 MRNLPFKATIEDILDFFYGYRVIPDSVsIRYNDDGQPTGDARVAFPSPREARRAVRELNNRPLGGR--KVKL 74

RNA recognition motif 2 (RRM2) found in Drosophila melanogaster Bruno protein and similar proteins; This subgroup corresponds to the RRM2 of Bruno, a Drosophila RNA recognition motif (RRM)-containing protein that plays a central role in regulation of Oskar (Osk) expression. It mediates repression by binding to regulatory Bruno response elements (BREs) in the Osk mRNA 3' UTR. The full-length Bruno protein contains three RRMs, two located in the N-terminal half of the protein and the third near the C-terminus, separated by a linker region.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYN 147
Cdd:cd12636    3 KLFVGMLSKKCNESDVRIMFSPYGSIEECTVLRDQNGKSRGCAFVTFTSRQCAVNAIKAMH 63

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 262263334   88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDG 153
Cdd:TIGR01628 181 LYVKNLDPSVNEDKLRELFAKFGEITSAAVMKDGSGRSRGFAFVNFEKHEDAAKAVEEMNGKKIGL 246

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 262263334  87 KLFLSNLHFGVSDAD-IQLLFAEFGTLKKSAVHYDRCGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIHLVTSQ 164
Cdd:cd12675    2 KLIIRNLPWSIKKPVhLKKLFGRYGKVVEATIPRKKGGKLSGFAFVTMKGRKNAEEALESVNGLEIDGRPVAVDWAVSK 80

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 262263334  87 KLFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNG 148
Cdd:cd12361    1 KLFVGMIPKTASEEDVRPLFEQFGNIEEVQILRDKqTGQSKGCAFVTFSTREEALRAIEALHN 63

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 262263334  88 LFLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMREYNGAPLDGRPMNIH 159
Cdd:cd12398    3 VFVGNIPYDATEEQLKEIFSEVGPVVSFRLVTDReTGKPKGYGFCEFRDAETALSAVRNLNGYELNGRPLRVD 75

RNA recognition motif 2 (RRM2) found in Arabidopsis thaliana phragmoplastin interacting protein 1 (PHIP1) and similar proteins; The CD corresponds to the RRM2 of PHIP1. A. thaliana PHIP1 and its homologs represent a novel class of plant-specific RNA-binding proteins that may play a unique role in the polarized mRNA transport to the vicinity of the cell plate. The family members consist of multiple functional domains, including a lysine-rich domain (KRD domain) that contains three nuclear localization motifs (KKKR/NK), two RNA recognition motifs (RRMs), and three CCHC-type zinc fingers. PHIP1 is a peripheral membrane protein and is localized at the cell plate during cytokinesis in plants. In addition to phragmoplastin, PHIP1 interacts with two Arabidopsis small GTP-binding proteins, Rop1 and Ran2. However, PHIP1 interacted only with the GTP-bound form of Rop1 but not the GDP-bound form. It also binds specifically to Ran2 mRNA.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 262263334  89 FLSNLHFGVSDADIQLLFAEFGTLKKSAVHYDR-CGRSLGTAHVHFERKADALKAMrEYNGAPLDGRPMNI 158
Cdd:cd12272    3 YIGNLAWDIDEDDLRELFAECCEITNVRLHTDKeTGEFKGYGHVEFADEESLDAAL-KLAGTKLCGRPIRV 72