Zn-finger in Ran binding protein and others;

                          10        20
                  ....*....|....*....|....*...
gi 568950486  210 RAGDWKCPnpTCENMNFSWRNECNQCKA 237
Cdd:pfam00641   1 REGDWDCS--KCLVQNFATSTKCVACQA 26

RNA recognition motif;

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486    74 TIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIK 153
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVES--------VRLVRDKETGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLK 72

                   .
gi 568950486   154 V 154
Cdd:smart00360  73 V 73

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  72 NNTIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNP 151
Cdd:COG0724    1 SMKIYVGNLPYSVTEEDLRELFSEYGEVTS--------VKLITDRETGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRT 72

                         90
                 ....*....|.
gi 568950486 152 IKVSFATRRAD 162
Cdd:COG0724   73 LKVNEARPREE 83

Zn-finger in Ran binding protein and others;

                          10        20
                  ....*....|....*....|....*...
gi 568950486  210 RAGDWKCPnpTCENMNFSWRNECNQCKA 237
Cdd:pfam00641   1 REGDWDCS--KCLVQNFATSTKCVACQA 26

Zinc finger domain; Zinc finger domain in Ran-binding proteins (RanBPs), and other proteins. In RanBPs, this domain binds RanGDP.

                           10        20
                   ....*....|....*....|....*.
gi 568950486   212 GDWKCPnpTCENMNFSWRNECNQCKA 237
Cdd:smart00547   1 GDWECP--ACTFLNFASRSKCFACGA 24

RNA recognition motif (RRM) found in vertebrate Ewing Sarcoma Protein (EWS); This subgroup corresponds to the RRM of EWS, also termed Ewing sarcoma breakpoint region 1 protein, a member of the FET (previously TET) (FUS/TLS, EWS, TAF15) family of RNA- and DNA-binding proteins whose expression is altered in cancer. It is a multifunctional protein and may play roles in transcription and RNA processing. EWS is involved in transcriptional regulation by interacting with the preinitiation complex TFIID and the RNA polymerase II (RNAPII) complexes. It is also associated with splicing factors, such as the U1 snRNP protein U1C, suggesting its implication in pre-mRNA splicing. Additionally, EWS has been shown to regulate DNA damage-induced alternative splicing (AS). Like other members in the FET family, EWS contains an N-terminal Ser, Gly, Gln and Tyr-rich region composed of multiple copies of a degenerate hexapeptide repeat motif. The C-terminal region consists of a conserved nuclear import and retention signal (C-NLS), a C2/C2 zinc-finger motif, a conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and at least 1 arginine-glycine-glycine (RGG)-repeat region. EWS specifically binds to poly G and poly U RNA. It also binds to the proximal-element DNA of the macrophage-specific promoter of the CSF-1 receptor gene.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  73 NTIFVQGLGENVTIESVADYFKQIGIIKTNKKTGQPMINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPI 152
Cdd:cd12533    1 STIYVQGLNENVTLEELADFFKHCGVVKINKRTGQPMINIYTDKETGKPKGDATVSYEDPPAAKAAVEWFDGKDFQGNKL 80

                 ...
gi 568950486 153 KVS 155
Cdd:cd12533   81 KVS 83

RNA recognition motif (RRM) found in Drosophila melanogaster RNA-binding protein cabeza and similar proteins; This subgroup corresponds to the RRM in cabeza, also termed P19, or sarcoma-associated RNA-binding fly homolog (SARFH). It is a putative homolog of human RNA-binding proteins FUS (also termed TLS or Pigpen or hnRNP P2), EWS (also termed EWSR1), TAF15 (also termed hTAFII68 or TAF2N or RPB56), and belongs to the of the FET (previously TET) (FUS/TLS, EWS, TAF15) family of RNA- and DNA-binding proteins whose expression is altered in cancer. It is a nuclear RNA binding protein that may play an important role in the regulation of RNA metabolism during fly development. Cabeza contains one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTNKKTGQPMINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12534    1 VFVSNLPPNTTEQDLAEHFGSIGIIKIDKKTGKPKIWLYKDKDTGEPKGEATVTYDDPHAASAAIEWFNNKDFMGNTIKV 80

                 ...
gi 568950486 155 SFA 157
Cdd:cd12534   81 SLA 83

RNA recognition motif 1 (RRM1) found in HIV Tat-specific factor 1 (Tat-SF1) and similar proteins; This subfamily corresponds to the RRM1 of Tat-SF1 and CUS2. Tat-SF1 is the cofactor for stimulation of transcriptional elongation by human immunodeficiency virus-type 1 (HIV-1) Tat. It is a substrate of an associated cellular kinase. Tat-SF1 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a highly acidic carboxyl-terminal half. The family also includes CUS2, a yeast homolog of human Tat-SF1. CUS2 interacts with U2 RNA in splicing extracts and functions as a splicing factor that aids assembly of the splicing-competent U2 snRNP in vivo. CUS2 also associates with PRP11 that is a subunit of the conserved splicing factor SF3a. Like Tat-SF1, CUS2 contains two RRMs as well.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  72 NNTIFVQGLGENVTIESVADYFKQIGIIKTNKKTGQPMINLYTDREtGKLKGEATVSFDDPPSAKAAIDWFDGKE-FSGN 150
Cdd:cd12281    1 NTNVYVSGLPLDITVEEFVELFSKCGIIMEDPETGEPKIKLYRDEN-GNLKGDALCCYLKEESVELALQLLDGTEiGRGY 79

                         90
                 ....*....|....
gi 568950486 151 PIKVSfatrRADFN 164
Cdd:cd12281   80 KIHVE----RAKFE 89

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 568950486   75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDrETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIK 153
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKS--------IRLVRD-ETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12324    9 IFVTGVHEEAQEEDIHDKFAEFGEIKN--------LHLNLDRRTGFVKGYALVEYETKKEAQAAIEGLNGKELLGQTISV 80

                 ....*...
gi 568950486 155 SFATRRAD 162
Cdd:cd12324   81 DWAFVKGP 88

RNA recognition motif (RRM) found in cyclophilin-33 (Cyp33) and similar proteins; This subfamily corresponds to the RRM of Cyp33, also termed peptidyl-prolyl cis-trans isomerase E (PPIase E), or cyclophilin E, or rotamase E. Cyp33 is a nuclear RNA-binding cyclophilin with an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal PPIase domain. Cyp33 possesses RNA-binding activity and preferentially binds to polyribonucleotide polyA and polyU, but hardly to polyG and polyC. It binds specifically to mRNA, which can stimulate its PPIase activity. Moreover, Cyp33 interacts with the third plant homeodomain (PHD3) zinc finger cassette of the mixed lineage leukemia (MLL) proto-oncoprotein and a poly-A RNA sequence through its RRM domain. It further mediates downregulation of the expression of MLL target genes HOXC8, HOXA9, CDKN1B, and C-MYC, in a proline isomerase-dependent manner. Cyp33 also possesses a PPIase activity that catalyzes cis-trans isomerization of the peptide bond preceding a proline, which has been implicated in the stimulation of folding and conformational changes in folded and unfolded proteins. The PPIase activity can be inhibited by the immunosuppressive drug cyclosporin A.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12347    1 LYVGGLAEEVDEKVLHAAFIPFGDIVD--------IQIPLDYETEKHRGFAFVEFEEAEDAAAAIDNMNESELFGRTIRV 72

                 ...
gi 568950486 155 SFA 157
Cdd:cd12347   73 NLA 75

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  73 NTIFVQGLGENVTIESVADYFKQIGiiktnkktgqPMIN--LYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGN 150
Cdd:cd12398    1 RSVFVGNIPYDATEEQLKEIFSEVG----------PVVSfrLVTDRETGKPKGYGFCEFRDAETALSAVRNLNGYELNGR 70

                 ....*..
gi 568950486 151 PIKVSFA 157
Cdd:cd12398   71 PLRVDFA 77

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIK 153
Cdd:cd21608    1 KLYVGNLSWDTTEDDLRDLFSEFGEVES--------AKVITDRETGRSRGFGFVTFSTAEAAEAAIDALNGKELDGRSIV 72

                 ....
gi 568950486 154 VSFA 157
Cdd:cd21608   73 VNEA 76

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKQIGIIKTNKktgqpminLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIK 153
Cdd:cd12447    1 TLFVGGLSWNVDDPWLKKEFEKYGGVISAR--------VITDRGSGRSKGYGYVDFATPEAAQKALAAMSGKEIDGRQIN 72

                 ....
gi 568950486 154 VSFA 157
Cdd:cd12447   73 VDFS 76

RNA recognition motif in type II polyadenylate-binding proteins; This subfamily corresponds to the RRM of type II polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 2 (PABP-2 or PABPN1), embryonic polyadenylate-binding protein 2 (ePABP-2 or PABPN1L) and similar proteins. PABPs are highly conserved proteins that bind to the poly(A) tail present at the 3' ends of most eukaryotic mRNAs. They have been implicated in the regulation of poly(A) tail length during the polyadenylation reaction, translation initiation, mRNA stabilization by influencing the rate of deadenylation and inhibition of mRNA decapping. ePABP-2 is predominantly located in the cytoplasm and PABP-2 is located in the nucleus. In contrast to the type I PABPs containing four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), the type II PABPs contains a single highly-conserved RRM. This subfamily also includes Saccharomyces cerevisiae RBP29 (SGN1, YIR001C) gene encoding cytoplasmic mRNA-binding protein Rbp29 that binds preferentially to poly(A). Although not essential for cell viability, Rbp29 plays a role in modulating the expression of cytoplasmic mRNA. Like other type II PABPs, Rbp29 contains one RRM only.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIktNKktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDwFDGKEFSGNPIKV 154
Cdd:cd12306    2 IYVGNVDYGTTPEELQAHFKSCGTI--NR------VTILCDKFTGQPKGFAYIEFVDKSSVENALL-LNESEFRGRQIKV 72

                 .
gi 568950486 155 S 155
Cdd:cd12306   73 T 73

RNA recognition motif (RRM) found in Helicobacter pylori HP0827 protein and similar proteins; This subfamily corresponds to the RRM of H. pylori HP0827, a putative ssDNA-binding protein 12rnp2 precursor, containing one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). The ssDNA binding may be important in activation of HP0827.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIkTNKKTgqPMinlytDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12399    1 LYVGNLPYSASEEQLKSLFGQFGAV-FDVKL--PM-----DRETKRPRGFGFVELQEEESAEKAIAKLDGTDFMGRTIRV 72

                 ...
gi 568950486 155 SFA 157
Cdd:cd12399   73 NEA 75

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTNKktgqpminLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12362    1 LFVYHLPNEFTDQDLYQLFAPFGNVVSAK--------VFVDKNTGRSKGFGFVSYDNPLSAQAAIKAMNGFQVGGKRLKV 72

                 .
gi 568950486 155 S 155
Cdd:cd12362   73 Q 73

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDwFDGKEFSGNPIK 153
Cdd:cd12272    1 TVYIGNLAWDIDEDDLRELFAECCEITN--------VRLHTDKETGEFKGYGHVEFADEESLDAALK-LAGTKLCGRPIR 71

                 ..
gi 568950486 154 VS 155
Cdd:cd12272   72 VD 73

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        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  72 NNTIFVQGLGENVTIESVADYFKQIG-IIKTNkktgqpminLYTDRetGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGN 150
Cdd:cd21605    1 ENSIFVGNLPFDCTWEDLKDHFSQVGeVIRAD---------IVTSR--GRHRGMGTVEFTNKEDVDRAISKFDHTMFMGR 69

                 ....
gi 568950486 151 PIKV 154
Cdd:cd21605   70 EIFV 73

RNA recognition motif 4 (RRM4) found in vertebrate nucleolin; This subfamily corresponds to the RRM4 of ubiquitously expressed protein nucleolin, also termed protein C23, is a multifunctional major nucleolar phosphoprotein that has been implicated in various metabolic processes, such as ribosome biogenesis, cytokinesis, nucleogenesis, cell proliferation and growth, cytoplasmic-nucleolar transport of ribosomal components, transcriptional repression, replication, signal transduction, inducing chromatin decondensation, etc. Nucleolin exhibits intrinsic self-cleaving, DNA helicase, RNA helicase and DNA-dependent ATPase activities. It can be phosphorylated by many protein kinases, such as the major mitotic kinase Cdc2, casein kinase 2 (CK2), and protein kinase C-zeta. Nucleolin shares similar domain architecture with gar2 from Schizosaccharomyces pombe and NSR1 from Saccharomyces cerevisiae. The highly phosphorylated N-terminal domain of nucleolin is made up of highly acidic regions separated from each other by basic sequences, and contains multiple phosphorylation sites. The central domain of nucleolin contains four closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which suggests that nucleolin is potentially able to interact with multiple RNA targets. The C-terminal RGG (or GAR) domain of nucleolin is rich in glycine, arginine and phenylalanine residues, and contains high levels of NG,NG-dimethylarginines.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKqigiiktnkktGQPMINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIK 153
Cdd:cd12406    2 TLFVKGLSEDTTEETLKEAFE-----------GAISARIATDRDTGSSKGFGFVDFSSEEDAKAAKEAMEDGEIDGNKVT 70

                 ....
gi 568950486 154 VSFA 157
Cdd:cd12406   71 LDFA 74

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
                 ....*....|....*....|....*....|....*....|....*...
gi 568950486 112 LYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKVSFATR 159
Cdd:cd12382   33 LMKDRETNKSRGFAFVTFESPADAKDAARDMNGKELDGKAIKVEQATK 80

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTNKktgqpminLYTDrETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12380    4 VYVKNFGEDVDDDELKELFEKYGKITSAK--------VMKD-DSGKSKGFGFVNFENHEAAQKAVEELNGKELNGKKLYV 74

                 ...
gi 568950486 155 SFA 157
Cdd:cd12380   75 GRA 77

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  67 QDNSDNNTIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKE 146
Cdd:cd12411    4 DEYKDSAYIYIGGLPYELTEGDILCVFSQYGEIVD--------INLVRDKKTGKSKGFAFLAYEDQRSTILAVDNLNGIK 75

                 ....*...
gi 568950486 147 FSGNPIKV 154
Cdd:cd12411   76 LLGRTIRV 83

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDwFDGKEFSGNPIK 153
Cdd:cd12395    1 SVFVGNLPFDIEEEELRKHFEDCGDVEA--------VRIVRDRETGIGKGFGYVLFKDKDSVDLALK-LNGSKLRGRKLR 71

                 ..
gi 568950486 154 VS 155
Cdd:cd12395   72 VK 73

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd21609    2 LYVGNIPRNVTSEELAKIFEEAGTVEI--------AEVMYDRYTGRSRGFGFVTMGSVEDAKAAIEKLNGTEVGGREIKV 73

                 ...
gi 568950486 155 SFA 157
Cdd:cd21609   74 NIT 76

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 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKV 154
Cdd:cd12449    3 LFVGGLSFDTNEQSLEEVFSKYGQISE--------VVVVKDRETQRSRGFGFVTFENPDDAKDAMMAMNGKSLDGRQIRV 74

                 ...
gi 568950486 155 SFA 157
Cdd:cd12449   75 DQA 77

RNA recognition motif 2 (RRM2) found in nucleolin-like proteins mainly from plants; This subfamily corresponds to the RRM2 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        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQG----LGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDwFDGKEFSG 149
Cdd:cd12451    1 TIFVKGfdasLGEDTIRDELREHFGECGEVTN--------VRIPTDRETGELKGFAYIEFSTKEAKEKALE-LNGSDIAG 71

                 ....*...
gi 568950486 150 NPIKVSFA 157
Cdd:cd12451   72 GNLVVDEA 79

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 568950486   62 RHDSEQDNSDNNTIFVQGLGENVTIESVADYFKQIGIIKTNKKtgqpMINlytdrETGKLKGEATVSFDDPPSAKAAIDW 141
Cdd:TIGR01628 275 LQQERKMKAQGVNLYVKNLDDTVTDEKLRELFSECGEITSAKV----MLD-----EKGVSRGFGFVCFSNPEEANRAVTE 345

                          90       100
                  ....*....|....*....|.
gi 568950486  142 FDGKEFSGNPIKVSFATRRAD 162
Cdd:TIGR01628 346 MHGRMLGGKPLYVALAQRKEQ 366

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFK-QIGIIKTnkktgqpMINLYTdrETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGN-PI 152
Cdd:cd12267    3 VIVSNLPKDVTEAQIREYFVsQIGPIKR-------VLLSYN--EGGKSTGIANITFKRAGDATKAYDKFNGRLDDGNrKM 73

                 ..
gi 568950486 153 KV 154
Cdd:cd12267   74 KV 75

RNA recognition motif 1 (RRM1) found in the Hu proteins family; This subfamily corresponds to the RRM1 of the Hu proteins family which represents a group of RNA-binding proteins involved in diverse biological processes. Since the Hu proteins share high homology with the Drosophila embryonic lethal abnormal vision (ELAV) protein, the Hu family is sometimes referred to as the ELAV family. Drosophila ELAV is exclusively expressed in neurons and is required for the correct differentiation and survival of neurons in flies. The neuronal members of the Hu family include Hu-antigen B (HuB or ELAV-2 or Hel-N1), Hu-antigen C (HuC or ELAV-3 or PLE21), and Hu-antigen D (HuD or ELAV-4), which play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. Hu-antigen R (HuR or ELAV-1 or HuA) is the ubiquitously expressed Hu family member. It has a variety of biological functions mostly related to the regulation of cellular response to DNA damage and other types of stress. HuR has an anti-apoptotic function during early cell stress response. It binds to mRNAs and enhances the expression of several anti-apoptotic proteins, such as p21waf1, p53, and prothymosin alpha. HuR also has pro-apoptotic function by promoting apoptosis when cell death is unavoidable. Furthermore, HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation. Hu proteins perform their cytoplasmic and nuclear molecular functions by coordinately regulating functionally related mRNAs. In the cytoplasm, Hu proteins recognize and bind to AU-rich RNA elements (AREs) in the 3' untranslated regions (UTRs) of certain target mRNAs, such as GAP-43, vascular epithelial growth factor (VEGF), the glucose transporter GLUT1, eotaxin and c-fos, and stabilize those ARE-containing mRNAs. They also bind and regulate the translation of some target mRNAs, such as neurofilament M, GLUT1, and p27. In the nucleus, Hu proteins function as regulators of polyadenylation and alternative splicing. Each Hu protein contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  77 VQGLGENVTIESVADYFKQIGIIKTNKktgqpminLYTDRETGKLKGEATVSFDDPPSAKAAIDWFDGKEFSGNPIKVSF 156
Cdd:cd12650    5 VNYLPQNMTQDEIRSLFSSIGEIESCK--------LIRDKVTGQSLGYGFVNYVDPSDAEKAINTLNGLRLQNKTIKVSY 76

                 .
gi 568950486 157 A 157
Cdd:cd12650   77 A 77

RNA recognition motif (RRM) found in eukaryotic translation initiation factor 4B (eIF-4B) and similar proteins; This subfamily corresponds to the RRM of eIF-4B, a multi-domain RNA-binding protein that has been primarily implicated in promoting the binding of 40S ribosomal subunits to mRNA during translation initiation. It contains two RNA-binding domains; the N-terminal well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), binds the 18S rRNA of the 40S ribosomal subunit and the C-terminal basic domain (BD), including two arginine-rich motifs (ARMs), binds mRNA during initiation, and is primarily responsible for the stimulation of the helicase activity of eIF-4A. eIF-4B also contains a DRYG domain (a region rich in Asp, Arg, Tyr, and Gly amino acids) in the middle, which is responsible for both, self-association of eIF-4B and binding to the p170 subunit of eIF3. Additional research indicates that eIF-4B can interact with the poly(A) binding protein (PABP) in mammalian cells, which can stimulate both, the eIF-4B-mediated activation of the helicase activity of eIF-4A and binding of poly(A) by PABP. eIF-4B has also been shown to interact specifically with the internal ribosome entry sites (IRES) of several picornaviruses which facilitate cap-independent translation initiation.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  74 TIFVQGLGENVTIESVADYFKQIGIIKtnkktgqpmINLYTDRETGKLKGEATVSFDDPPSAKAAIDwFDGKEFSGNPIK 153
Cdd:cd12402    4 TAYLGNLPYDVTEDDIEDFFRGLNISS---------VRLPRENGPGRLRGFGYVEFEDRESLIQALS-LNEESLKNRRIR 73

                 ....*..
gi 568950486 154 VSFATRR 160
Cdd:cd12402   74 VDVAGQA 80

RNA recognition motif (RRM) found in eukaryotic RNA-binding protein RBM24, RBM38 and similar proteins; This subfamily corresponds to the RRM of RBM24 and RBM38 from vertebrate, SUPpressor family member SUP-12 from Caenorhabditis elegans and similar proteins. Both, RBM24 and RBM38, are preferentially expressed in cardiac and skeletal muscle tissues. They regulate myogenic differentiation by controlling the cell cycle in a p21-dependent or -independent manner. RBM24, also termed RNA-binding region-containing protein 6, interacts with the 3'-untranslated region (UTR) of myogenin mRNA and regulates its stability in C2C12 cells. RBM38, also termed CLL-associated antigen KW-5, or HSRNASEB, or RNA-binding region-containing protein 1(RNPC1), or ssDNA-binding protein SEB4, is a direct target of the p53 family. It is required for maintaining the stability of the basal and stress-induced p21 mRNA by binding to their 3'-UTRs. It also binds the AU-/U-rich elements in p63 3'-UTR and regulates p63 mRNA stability and activity. SUP-12 is a novel tissue-specific splicing factor that controls muscle-specific splicing of the ADF/cofilin pre-mRNA in C. elegans. All family members contain a conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTNKktgqpminLYTDRETGKLKGEATVSFDDPPSAKAAIDwfdgkefSGNPIkv 154
Cdd:cd12384    3 IFVGGLPYHTTDDSLREYFEQFGEIEEAV--------VITDRQTGKSRGYGFVTMADREAAERACK-------DPNPI-- 65

                         90
                 ....*....|
gi 568950486 155 sFATRRADFN 164
Cdd:cd12384   66 -IDGRKANVN 74

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) and similar proteins; This subgroup corresponds to the RRM2 of hnRNP A2/B1, an RNA trafficking response element-binding protein that interacts with the hnRNP A2 response element (A2RE). Many mRNAs, such as myelin basic protein (MBP), myelin-associated oligodendrocytic basic protein (MOBP), carboxyanhydrase II (CAII), microtubule-associated protein tau, and amyloid precursor protein (APP) are trafficked by hnRNP A2/B1. hnRNP A2/B1 also functions as a splicing factor that regulates alternative splicing of the tumor suppressors, such as BIN1, WWOX, the antiapoptotic proteins c-FLIP and caspase-9B, the insulin receptor (IR), and the RON proto-oncogene among others. Overexpression of hnRNP A2/B1 has been described in many cancers. It functions as a nuclear matrix protein involving in RNA synthesis and the regulation of cellular migration through alternatively splicing pre-mRNA. It may play a role in tumor cell differentiation. hnRNP A2/B1 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a long glycine-rich region at the C-terminus.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 568950486  75 IFVQGLGENVTIESVADYFKQIGIIKTnkktgqpmINLYTDRETGKLKGEATVSFDD 131
Cdd:cd12581    3 LFVGGIKEDTEEHHLRDYFEEYGKIDT--------IEIITDRQSGKKRGFGFVTFDD 51