heterogeneous nuclear ribonucleoprotein R, Q family; Sequences in this subfamily include the human heterogeneous nuclear ribonucleoproteins (hnRNP) R, Q, and APOBEC-1 complementation factor (aka APOBEC-1 stimulating protein). These proteins contain three RNA recognition domains (rrm: pfam00076) and a somewhat variable C-terminal domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   10 NKTALLAWVKETGIHLVQVNGQRKYGGPPPGWVGDPPPSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLN 89
Cdd:TIGR01648  19 DEAALKALLERTGYTLVQENGQRKYGGPPPGWSGVQPGRGCEVFVGKIPRDLYEDELVPLFEKAGPIYELRLMMDFSGQN 98

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   90 RGFAYAKYSDCRSAQVAITTLNNFEVQKGCLIMVCKSTEKCELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRK 169
Cdd:TIGR01648  99 RGYAFVTFCGKEEAKEAVKLLNNYEIRPGRLLGVCISVDNCRLFVGGIPKNKKREEILEEFSKVTEGVVDVIVYHSAADK 178

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|....
gi 557322230  170 QGQ--LAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDWLKPE 211
Cdd:TIGR01648 179 KKNrgFAFVEYESHRAAAMARRKLMPGRIQLWGHVIAVDWAEPE 222

heterogeneous nuclear ribonucleoprotein R, Q family; Sequences in this subfamily include the human heterogeneous nuclear ribonucleoproteins (hnRNP) R, Q, and APOBEC-1 complementation factor (aka APOBEC-1 stimulating protein). These proteins contain three RNA recognition domains (rrm: pfam00076) and a somewhat variable C-terminal domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   10 NKTALLAWVKETGIHLVQVNGQRKYGGPPPGWVGDPPPSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLN 89
Cdd:TIGR01648  19 DEAALKALLERTGYTLVQENGQRKYGGPPPGWSGVQPGRGCEVFVGKIPRDLYEDELVPLFEKAGPIYELRLMMDFSGQN 98

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   90 RGFAYAKYSDCRSAQVAITTLNNFEVQKGCLIMVCKSTEKCELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRK 169
Cdd:TIGR01648  99 RGYAFVTFCGKEEAKEAVKLLNNYEIRPGRLLGVCISVDNCRLFVGGIPKNKKREEILEEFSKVTEGVVDVIVYHSAADK 178

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|....
gi 557322230  170 QGQ--LAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDWLKPE 211
Cdd:TIGR01648 179 KKNrgFAFVEYESHRAAAMARRKLMPGRIQLWGHVIAVDWAEPE 222

double-stranded RNA binding motif of dead end protein homolog 1 (DND1) and similar proteins; DND1 (also known as dead end protein, or RNA-binding motif single-stranded-interacting protein 4 (RBMS4)) is an RNA-binding protein that is required for the survival of primordial germ cells (PGCs) and suppresses the formation of germ-cell tumors. DND1 binds a UU(A/U) trinucleotide motif predominantly in the 3' untranslated regions of mRNA, and destabilizes target mRNAs. It also counteracts the function of several microRNAs (miRNAs), which are inhibitors of gene expression, by binding mRNAs and prohibiting miRNAs from associating with their target sites. DND1 contains two RNA recognition motifs (RRMs) and a C-terminal double-stranded RNA binding motif (DSRM) that is not sequence specific, but highly specific for dsRNAs of various origin and structure.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230 255 SMLDYLSALCKKQQLGEPVYLTKCVQVNPDGWMRFWYQVVIPGYPSPFRGFIWIKPDQSGLGEHEKAKNAAAFQVLKTLG 334
Cdd:cd20313    1 DAVALLNKLCQKLRLGSPVYLTKLLGAGPDGFLRFWFKVVIPGLPLPFTGFVWVLPGPLARAGHEEAKQAAAQQVLQALG 80

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230    52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQKGCL 120
Cdd:smart00360   2 LFVGNLPPDTTEEELRELFSKFGKVESVRLVRdKETGKSKGFAFVEFESEEDAEKALEALNGKELDGRPL 71

heterogeneous nuclear ribonucleoprotein R, Q family; Sequences in this subfamily include the human heterogeneous nuclear ribonucleoproteins (hnRNP) R, Q, and APOBEC-1 complementation factor (aka APOBEC-1 stimulating protein). These proteins contain three RNA recognition domains (rrm: pfam00076) and a somewhat variable C-terminal domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   10 NKTALLAWVKETGIHLVQVNGQRKYGGPPPGWVGDPPPSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLN 89
Cdd:TIGR01648  19 DEAALKALLERTGYTLVQENGQRKYGGPPPGWSGVQPGRGCEVFVGKIPRDLYEDELVPLFEKAGPIYELRLMMDFSGQN 98

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230   90 RGFAYAKYSDCRSAQVAITTLNNFEVQKGCLIMVCKSTEKCELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRK 169
Cdd:TIGR01648  99 RGYAFVTFCGKEEAKEAVKLLNNYEIRPGRLLGVCISVDNCRLFVGGIPKNKKREEILEEFSKVTEGVVDVIVYHSAADK 178

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|....
gi 557322230  170 QGQ--LAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDWLKPE 211
Cdd:TIGR01648 179 KKNrgFAFVEYESHRAAAMARRKLMPGRIQLWGHVIAVDWAEPE 222

double-stranded RNA binding motif of dead end protein homolog 1 (DND1) and similar proteins; DND1 (also known as dead end protein, or RNA-binding motif single-stranded-interacting protein 4 (RBMS4)) is an RNA-binding protein that is required for the survival of primordial germ cells (PGCs) and suppresses the formation of germ-cell tumors. DND1 binds a UU(A/U) trinucleotide motif predominantly in the 3' untranslated regions of mRNA, and destabilizes target mRNAs. It also counteracts the function of several microRNAs (miRNAs), which are inhibitors of gene expression, by binding mRNAs and prohibiting miRNAs from associating with their target sites. DND1 contains two RNA recognition motifs (RRMs) and a C-terminal double-stranded RNA binding motif (DSRM) that is not sequence specific, but highly specific for dsRNAs of various origin and structure.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230 255 SMLDYLSALCKKQQLGEPVYLTKCVQVNPDGWMRFWYQVVIPGYPSPFRGFIWIKPDQSGLGEHEKAKNAAAFQVLKTLG 334
Cdd:cd20313    1 DAVALLNKLCQKLRLGSPVYLTKLLGAGPDGFLRFWFKVVIPGLPLPFTGFVWVLPGPLARAGHEEAKQAAAQQVLQALG 80

RNA recognition motif 2 (RRM2) found in vertebrate dead end protein homolog 1 (DND1); This subgroup corresponds to the RRM2 of DND1, also termed RNA-binding motif, single-stranded-interacting protein 4. It is an RNA-binding protein that is essential for maintaining viable germ cells in vertebrates. It interacts with the 3'-untranslated region (3'-UTR) of multiple messenger RNAs (mRNAs) and prevents micro-RNA (miRNA) mediated repression of mRNA. For instance, DND1 binds cell cycle inhibitor, P27 (p27Kip1, CDKN1B), and cell cycle regulator and tumor suppressor, LATS2 (large tumor suppressor, homolog 2 of Drosophila). It helps maintain their protein expression through blocking the inhibitory function of microRNAs (miRNA) from these transcripts. DND1 may also impose another level of translational regulation to modulate expression of critical factors in embryonic stem (ES) cells. Moreover, DND1 interacts specifically with apolipoprotein B editing complex 3 (APOBEC3), a multi-functional protein inhibiting retroviral replication. The DND1-APOBEC3 interaction may play a role in maintaining viability of germ cells and for preventing germ cell tumor development. DND1 contains two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230 128 EKCELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRKQGQLAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDW 207
Cdd:cd12493    1 EKCELSVDGLPVSMDESKLLMVLQMLTDGVESVLLHPSPPKGKEVLAVVKYSSHRAAAMAKKALVEGSRNLCGEQVTVRW 80

                 ...
gi 557322230 208 LKP 210
Cdd:cd12493   81 LKP 83

RNA recognition motif 1 (RRM1) found in vertebrate APOBEC-1 complementation factor (ACF); This subgroup corresponds to the RRM1 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. It 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 557322230  49 GSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQKGCLIMVCKS 126
Cdd:cd12486    1 GCEIFIGKLPRDLFEDELVPLCEKIGKIYEMRMMMDFNGNNRGYAFVTFSNKQEARNAIKQLNNYEIRNGRLLGVCAS 78

double strand RNA binding domain from DEAD END PROTEIN 1; A C-terminal domain in human dead end protein 1 (DND1_HUMAN) homologous to double strand RNA binding domains (PF00035, PF00333)

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  255 SMLDYLsalCKKQQLGEPVYLTKCVqVNPDGWMRFWYQVVIPGYPSPFRGFIWIKPDQSGLGEHEKAKNAAAFQVLKTLG 334
Cdd:pfam14709   5 SHLEEL---CQKNKWGSPVYELHST-AGPDGKQLFTYKVVIPGIETPFPGVIWIFMPGKLCSTKEEAKEAAAEQVLEALG 80

RNA recognition motif 1 (RRM1) found in vertebrate heterogeneous nuclear ribonucleoprotein Q (hnRNP Q); This subgroup corresponds to the RRM1 of hnRNP Q, also termed glycine- and tyrosine-rich RNA-binding protein (GRY-RBP), or NS1-associated protein 1 (NASP1), or synaptotagmin-binding, cytoplasmic RNA-interacting protein (SYNCRIP). It is a ubiquitously expressed nuclear RNA-binding protein identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome. As an alternatively spliced version of NSAP, it acts as an interaction partner of a multifunctional protein required for viral replication, and is implicated in the regulation of specific mRNA transport. hnRNP Q has also been identified as SYNCRIP, a dual functional protein participating in both viral RNA replication and translation. As a synaptotagmin-binding protein, hnRNP Q plays a putative role in organelle-based mRNA transport along the cytoskeleton. Moreover, hnRNP Q has been found in protein complexes involved in translationally coupled mRNA turnover and mRNA splicing. It functions as a wild-type survival motor neuron (SMN)-binding protein that may participate in pre-mRNA splicing and modulate mRNA transport along microtubuli. hnRNP Q contains an acidic auxiliary N-terminal region, followed by two well-defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RGG motif; hnRNP Q binds RNA through its RRM domains.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  46 PPSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMT-FSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQKGCLIMVC 124
Cdd:cd12483    2 PSVGTEIFVGKIPRDLFEDELVPLFEKAGPIWDLRLMMDpLTGLNRGYAFVTFCTKEAAQEAVKLCNNHEIRPGKHIGVC 81

                 ..
gi 557322230 125 KS 126
Cdd:cd12483   82 IS 83

RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein 46 (RBM46); This subgroup corresponds to the RRM2 of RBM46, also termed cancer/testis antigen 68 (CT68). It is a putative RNA-binding protein that shows high sequence homology with heterogeneous nuclear ribonucleoprotein R (hnRNP R) and heterogeneous nuclear ribonucleoprotein Q (hnRNP Q). Its biological function remains unclear. Like hnRNP R and hnRNP Q, RBM46 contains two well-defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230 128 EKCELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRKQGQ--LAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHV 205
Cdd:cd12492    1 DNCRLFIGAIPKEKKKEEILEEMKKVTEGVVDVIVYPSATDKTKNrgFAFVEYESHRAAAMARRKLIPGTFQLWGHTIQV 80

                 ....*
gi 557322230 206 DWLKP 210
Cdd:cd12492   81 DWADP 85

RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein 47 (RBM47); This subgroup corresponds to the RRM2 of RBM47, a putative RNA-binding protein that shows high sequence homology with heterogeneous nuclear ribonucleoprotein R (hnRNP R) and heterogeneous nuclear ribonucleoprotein Q (hnRNP Q). Its biological function remains unclear. Like hnRNP R and hnRNP Q, RBM47 contains two well-defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230 130 CELCMDGLPSSVSLGQLQMVLQEVTTGVKNVSLYPNPSRKQGQ--LAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDW 207
Cdd:cd12491    4 CRLFIGGIPKMKKREEILEEISKVTEGVLDVIVYASAADKMKNrgFAFVEYESHRAAAMARRKLMPGRIQLWGHQIAVDW 83

                 ....*
gi 557322230 208 LKPEM 212
Cdd:cd12491   84 AEPEI 88

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTF-SGLNRGFAYAKYSDCRSAQVAITTLNNFE 114
Cdd:cd12398    3 VFVGNIPYDATEEQLKEIFSEVGPVVSFRLVTDReTGKPKGYGFCEFRDAETALSAVRNLNGYE 66

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 557322230   52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVqKGCLIM 122
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRDETGRSKGFAFVEFEDEEDAEKAIEALNGKEL-GGRELK 70

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 557322230  53 FIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFS-GLNRGFAYAKYSDCRSAQVAITTLNNFEVQKGC 119
Cdd:cd12361    3 FVGMIPKTASEEDVRPLFEQFGNIEEVQILRDKQtGQSKGCAFVTFSTREEALRAIEALHNKKTMPGC 70

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEV 115
Cdd:cd12362    1 LFVYHLPNEFTDQDLYQLFAPFGNVVSAKVFVdKNTGRSKGFGFVSYDNPLSAQAAIKAMNGFQV 65

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 557322230  54 IGKLPQDMYENKLIPLFQSVGKLYEFRLMMTF-SGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12375    4 VNYLPQSMTQEELRSLFGAIGPIESCKLVRDKiTGQSLGYGFVNYRDPNDARKAINTLNGLDLE 67

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), cleavage stimulation factor subunit 2 tau variant (CSTF2T) and similar proteins; This subgroup 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.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTF-SGLNRGFAYAKYSDCRSAQVAITTLNNFEV 115
Cdd:cd12671    9 VFVGNIPYEATEEQLKDIFSEVGPVVSFRLVYDReTGKPKGYGFCEYQDQETALSAMRNLNGYEL 73

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMtfsglNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12354    3 VYVGNITKGLTEALLQQTFSPFGQILEVRVFP-----DKGYAFIRFDSHEAATHAIVSVNGTIIN 62

RNA recognition motif 1 (RRM1) found in vertebrate Hu-antigen B (HuB); This subgroup corresponds to the RRM1 of HuB, also termed ELAV-like protein 2 (ELAV-2), or ELAV-like neuronal protein 1, or nervous system-specific RNA-binding protein Hel-N1 (Hel-N1), one of the neuronal members of the Hu family. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads and is up-regulated during neuronal differentiation of embryonic carcinoma P19 cells. Like other Hu proteins, HuB contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  48 SGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12771    3 SKTNLIVNYLPQNMTQEELKSLFGSIGEIESCKLVRdKITGQSLGYGFVNYIEPKDAEKAINTLNGLRLQ 72

RNA recognition motif 1 (RRM1) found in vertebrate Hu-antigen C (HuC); This subgroup corresponds to the RRM1 of HuC, also termed ELAV-like protein 3 (ELAV-3), or paraneoplastic cerebellar degeneration-associated antigen, or paraneoplastic limbic encephalitis antigen 21 (PLE21), one of the neuronal members of the Hu family. The neuronal Hu proteins play important roles in neuronal differentiation, plasticity and memory. Like other Hu proteins, HuC contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an AU-rich RNA element (ARE). The AU-rich element binding of HuC can be inhibited by flavonoids. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  48 SGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12772    3 SKTNLIVNYLPQNMTQEEFKSLFGSIGDIESCKLVRdKITGQSLGYGFVNYVDPNDADKAINTLNGLKLQ 72

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAIT 108
Cdd:cd12391    2 VFVSNLDYSVPEDKIREIFSGCGEITDVRLVKNYKGKSKGYCYVEFKDEESAQKALK 58

RNA recognition motif 1 (RRM1) found in Drosophila sex-lethal (SXL) and similar proteins; This subfamily corresponds to the RRM1 of SXL which governs sexual differentiation and X chromosome dosage compensation in Drosophila melanogaster. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds also to its own pre-mRNA and promotes female-specific alternative splicing. SXL contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 557322230  54 IGKLPQDMYENKLIPLFQSVGKLYEFRLMMTF-SGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12649    5 VNYLPQDLTDREFRALFRAIGPVNTCKIVRDKkTGYSYGFGFVDFTSEEDAQRAIKTLNGLQLQ 68

RNA recognition motif 3 (RRM3) found in Drosophila melanogaster Bruno protein and similar proteins; This subgroup corresponds to the RRM3 of Bruno protein, 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        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  47 PSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEV 115
Cdd:cd12640    2 PEGCNLFIYHLPQEFTDTDLAQTFLPFGNVISAKVFIdKQTNLSKCFGFVSYDNPDSAQAAIQAMNGFQI 71

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNFEV 115
Cdd:cd12380    4 VYVKNFGEDVDDDELKELFEKYGKITSAKVMKDDSGKSKGFGFVNFENHEAAQKAVEELNGKEL 67

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  47 PSGSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMT-FSGLNRGFAYAKYSDCRSAQVAITTLNNFEV 115
Cdd:cd12639    2 PEGCNLFIYHLPQEFGDAELMQMFLPFGNVISAKVFVDrATNQSKCFGFVSFDNPASAQAAIQAMNGFQI 71

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 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12392    5 LFVKGLPFSCTKEELEELFKQHGTVKDVRLVTYRNGKPKGLAYVEYENEADASQAVLKTDGTEIK 69

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRlMMTF--SGLNRGFAYAKYSDCRSAQVAI 107
Cdd:cd12397    1 LFVGNLSFETTEEDLRKHFAPAGKIRKVR-MATFedSGKCKGFAFVDFKEIESATNAV 57

RNA recognition motif in nucleolar protein interacting with the FHA domain of pKI-67 (NIFK) and similar proteins; This subgroup corresponds to the RRM of NIFK and Nop15p. NIFK, also termed MKI67 FHA domain-interacting nucleolar phosphoprotein, or nucleolar phosphoprotein Nopp34, is a putative RNA-binding protein interacting with the forkhead associated (FHA) domain of pKi-67 antigen in a mitosis-specific and phosphorylation-dependent manner. It is nucleolar in interphase but associates with condensed mitotic chromosomes. This family also includes Saccharomyces cerevisiae YNL110C gene encoding ribosome biogenesis protein 15 (Nop15p), also termed nucleolar protein 15. Both, NIFK and Nop15p, contain an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNF 113
Cdd:cd12307    2 VYIGHLPHGFYEPELRKYFSQFGTVTRLRLSRsKKTGKSKGYAFVEFEDPEVAKIVAETMNNY 64

double-stranded RNA binding motif of APOBEC1 complementation factor (A1CF) and similar proteins; A1CF (also known as APOBEC1-stimulating protein) is an essential component of the apolipoprotein B mRNA editing enzyme complex which is responsible for the posttranscriptional editing of a CAA codon for Gln to a UAA codon for stop in APOB mRNA. A1CF binds to APOB mRNA and is probably responsible for docking the catalytic subunit, APOBEC1, to the mRNA to allow it to deaminate its target cytosine. It contains three RNA recognition motifs (RRMs) and a C-terminal double-stranded RNA binding motif (DSRM) that is not sequence specific, but highly specific for dsRNAs of various origin and structure.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 557322230 259 YLSALCKKQQLGEPVYlTKCVQVNPDGWMRFWYQVVIPGYPSPFRGFIWIKPDQSGLgEHEKAKNAAAFQVLKTLGCP 336
Cdd:cd19900    6 ILEEICQKNNWGQPVY-QLHSTIGPDQRQLFLYKVTIPALASQYPNITPFQPNKLCR-SVEEAKSYAAEYTLQQLGIP 81

RNA recognition motif 2 (RRM2) found in vertebrate heterogeneous nuclear ribonucleoprotein R (hnRNP R); This subgroup corresponds to the RRM2 of hnRNP R, a ubiquitously expressed nuclear RNA-binding protein that specifically bind mRNAs with a preference for poly(U) stretches. Upon binding of RNA, hnRNP R forms oligomers, most probably dimers. hnRNP R has been implicated in mRNA processing and mRNA transport, and also acts as a regulator to modify binding to ribosomes and RNA translation. hnRNP R is predominantly located in axons of motor neurons and to a much lower degree in sensory axons. In axons of motor neurons, it also functions as a cytosolic protein and interacts with wild type of survival motor neuron (SMN) proteins directly, further providing a molecular link between SMN and the spliceosome. Moreover, hnRNP R plays an important role in neural differentiation and development, as well as in retinal development and light-elicited cellular activities. It contains an acidic auxiliary N-terminal region, followed by two well-defined and one degenerated RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal RGG motif. hnRNP R binds RNA through its RRM domains.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 557322230 150 LQEVTTGVKNVSLY--PNPSRKQGQLAVLKYHSHWAAAMAKKTLAEGNLDLHGEEIHVDWLKP 210
Cdd:cd12488   23 FSKVTEGLVDVILYhqPDDKKKNRGFCFLEYEDHKSAAQARRRLMSGKVKVWGNVVTVEWADP 85

RNA recognition motif 2 (RRM2) found in Drosophila sex-lethal (SXL) and similar proteins; This subfamily corresponds to the RRM2 of the sex-lethal protein (SXL) which governs sexual differentiation and X chromosome dosage compensation in Drosophila melanogaster. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds also to its own pre-mRNA and promotes female-specific alternative splicing. SXL contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 557322230  49 GSEVFIGKLPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNN 112
Cdd:cd12651    2 DTNLYVTNLPRTITEDELDTIFGAYGNIVQKNLLRdKLTGRPRGVAFVRYDKREEAQAAISALNG 66

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 557322230  57 LPQDMYENKLIPLFQSVGKLYEFRLMM-TFSGLNRGFAYAKYSDCRSAQVAITTLNNFEVQ 116
Cdd:cd12650    8 LPQNMTQDEIRSLFSSIGEIESCKLIRdKVTGQSLGYGFVNYVDPSDAEKAINTLNGLRLQ 68

RNA recognition motif 3 (RRM3) 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 third RRM motif.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNF 113
Cdd:cd21607    5 IYCSNLPLSTAESDLYDLFETIGKVNNAELKYDETGDPTGSAVVEYENLDDADVCISKLNNY 66

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 557322230  52 VFIGKLPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLN 111
Cdd:cd12635    4 LFVGMLGKQQSEDDVRRLFEPFGSIEECTILRGPDGNSKGCAFVKFSSHAEAQAAINALH 63

RNA recognition motif 1 (RRM1) found in RNA-binding protein 19 (RBM19) and similar proteins; This subgroup corresponds to the RRM1 of RBM19, also termed RNA-binding domain-1 (RBD-1), a nucleolar protein conserved in eukaryotes. It is involved in ribosome biogenesis by processing rRNA. In addition, it is essential for preimplantation development. RBM19 has a unique domain organization containing 6 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 557322230  57 LPQDMYENKLIPLFQSVGKLYEFRLMMTFSGLNRGFAYAKYSDCRSAQVAITTLNNfevqkgCLIMVCKSTekCELC 133
Cdd:cd12564    8 LPSSITEDRLRKLFSAFGTITDVQLKYTKDGKFRRFGFVGFKSEEEAQKALKHFNN------SFIDTSRIT--VEEC 76