RNA recognition motif (RRM) found in Tudor domain-containing protein 10 (TDRD10) and similar proteins; TDRD10 is widely expressed and localized both to the nucleus and cytoplasm and may play general roles like regulation of RNA metabolism. It contains a Tudor domain and a RNA recognition motif (RRM).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1331831441  35 EVYVGNLPLDISKEEILYLLKDFNPLDVHKIQNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVN 103
Cdd:cd21617     1 EVYVGNLPLDISEEEILQLFKAFNPVLVKKIRSGFKCFAFVDLGSDENVKLAIQQLNGTLFGGRRLVVN 69

RNA recognition motif (RRM) found in Tudor domain-containing protein 10 (TDRD10) and similar proteins; TDRD10 is widely expressed and localized both to the nucleus and cytoplasm and may play general roles like regulation of RNA metabolism. It contains a Tudor domain and a RNA recognition motif (RRM).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1331831441  35 EVYVGNLPLDISKEEILYLLKDFNPLDVHKIQNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVN 103
Cdd:cd21617     1 EVYVGNLPLDISEEEILQLFKAFNPVLVKKIRSGFKCFAFVDLGSDENVKLAIQQLNGTLFGGRRLVVN 69

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441  37 YVGNLPLDISKEEILYLLKDFNplDVHKIQ-------NGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVNTSKRPP 109
Cdd:COG0724     5 YVGNLPYSVTEEDLRELFSEYG--EVTSVKlitdretGRSRGFGFVEMPDDEEAQAAIEALNGAELMGRTLKVNEARPRE 82

                  ..
gi 1331831441 110 KR 111
Cdd:COG0724    83 ER 84

Tudor domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441 219 LHQNMQALFSTLAQaeeqqpylEGSTVTRGTRCLAEYHLGDyghAWNRCWVL-DRVDTWAVVMFIDFGQLATIPVQSLRS 297
Cdd:pfam00567  30 LTEELQEYYASKPP--------ESLPPAVGDGCVAAFSEDG---KWYRAKITeSLDDGLVEVLFIDYGNTETVPLSDLRP 98

                          90
                  ....*....|....*...
gi 1331831441 298 LDSdDFWTIPPLTQPFML 315
Cdd:pfam00567  99 LPP-ELESLPPQAIKCQL 115

RNA recognition motif (RRM) found in Tudor domain-containing protein 10 (TDRD10) and similar proteins; TDRD10 is widely expressed and localized both to the nucleus and cytoplasm and may play general roles like regulation of RNA metabolism. It contains a Tudor domain and a RNA recognition motif (RRM).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1331831441  35 EVYVGNLPLDISKEEILYLLKDFNPLDVHKIQNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVN 103
Cdd:cd21617     1 EVYVGNLPLDISEEEILQLFKAFNPVLVKKIRSGFKCFAFVDLGSDENVKLAIQQLNGTLFGGRRLVVN 69

RNA recognition motif (RRM) superfamily; RRM, also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), is a highly abundant domain in eukaryotes found in proteins involved in post-transcriptional gene expression processes including mRNA and rRNA processing, RNA export, and RNA stability. This domain is 90 amino acids in length and consists of a four-stranded beta-sheet packed against two alpha-helices. RRM usually interacts with ssRNA, but is also known to interact with ssDNA as well as proteins. RRM binds a variable number of nucleotides, ranging from two to eight. The active site includes three aromatic side-chains located within the conserved RNP1 and RNP2 motifs of the domain. The RRM domain is found in a variety heterogeneous nuclear ribonucleoproteins (hnRNPs), proteins implicated in regulation of alternative splicing, and protein components of small nuclear ribonucleoproteins (snRNPs).

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLD----VHKIQNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVN 103
Cdd:cd00590     1 LFVGNLPPDTTEEDLRELFSKFGEVVsvriVRDRDGKSKGFAFVEFESPEDAEKALEALNGTELGGRPLKVS 72

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLDV----HKIQNGCKCF------AFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd12409     2 VYISNLSYSTTEEELEELLKDYKPVSVlipsYTVRGFRSRKhrplgiAYAEFSSVEEAEKVVKDLNGKVFKGRKLFV 78

RNA recognition motif 1 (RRM1) found in vertebrate RRM-containing coactivator activator/modulator (CoAA); This subgroup corresponds to the RRM1 of CoAA, also termed RNA-binding protein 14 (RBM14), or paraspeckle protein 2 (PSP2), or synaptotagmin-interacting protein (SYT-interacting protein), a heterogeneous nuclear ribonucleoprotein (hnRNP)-like protein identified as a nuclear receptor coactivator. It mediates transcriptional coactivation and RNA splicing effects in a promoter-preferential manner and is enhanced by thyroid hormone receptor-binding protein (TRBP). CoAA contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a TRBP-interacting domain. It stimulates transcription through its interactions with coactivators, such as TRBP and CREB-binding protein CBP/p300, via the TRBP-interacting domain and interaction with an RNA-containing complex, such as DNA-dependent protein kinase-poly(ADP-ribose) polymerase complexes, via the RRMs.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1331831441  35 EVYVGNLPLDISKEEILYLlkdFNPldVHKIQNgC---KCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVNTS 105
Cdd:cd12608     2 KIFVGNVDEDTSQEELSAL---FEP--YGAVLS-CavmKQFAFVHMRGEAAADRAIRELNGRELHGRALVVEES 69

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1331831441  34 TEVYVGNLPLDISKEEILYLLKDFNPLDVHKI---QNG-CKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd12380     2 TNVYVKNFGEDVDDDELKELFEKYGKITSAKVmkdDSGkSKGFGFVNFENHEAAQKAVEELNGKELNGKKLYV 74

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 1331831441  35 EVYVGNLPLDISKEEILYLLKDFNplDVHKIQNGC-------KCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVNTSKR 107
Cdd:cd21609     1 RLYVGNIPRNVTSEELAKIFEEAG--TVEIAEVMYdrytgrsRGFGFVTMGSVEDAKAAIEKLNGTEVGGREIKVNITEK 78

                  .
gi 1331831441 108 P 108
Cdd:cd21609    79 P 79

Tudor domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441 219 LHQNMQALFSTLAQaeeqqpylEGSTVTRGTRCLAEYHLGDyghAWNRCWVL-DRVDTWAVVMFIDFGQLATIPVQSLRS 297
Cdd:pfam00567  30 LTEELQEYYASKPP--------ESLPPAVGDGCVAAFSEDG---KWYRAKITeSLDDGLVEVLFIDYGNTETVPLSDLRP 98

                          90
                  ....*....|....*...
gi 1331831441 298 LDSdDFWTIPPLTQPFML 315
Cdd:pfam00567  99 LPP-ELESLPPQAIKCQL 115

RNA recognition motif 3 (RRM3) found in Saccharomyces cerevisiae protein PES4, protein MIP6 and similar proteins; The family includes PES4 (also called DNA polymerase epsilon suppressor 4) and MIP6 (also called MEX67-interacting protein 6), both of which are predicted RNA binding proteins that may act as regulators of late translation, protection, and mRNA localization. MIP6 acts as a novel factor for nuclear mRNA export, binds to both poly(A)+ RNA and nuclear pores. It interacts with MEX67. Members in this family contain four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the third RRM motif.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPL------DVHKIQNgckCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd21603     3 IFVKNLPLDTNNDEILDFFSKVGPIksvftsPKYKYNS---LWAFVTYKKGSDTEKAIKLLNGTLFKGRTIEV 72

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLDVHKI----QNG-CKCFAFVDLGSMQKVTLAIQeLNGKLFHKRKLFV 102
Cdd:cd12395     2 VFVGNLPFDIEEEELRKHFEDCGDVEAVRIvrdrETGiGKGFGYVLFKDKDSVDLALK-LNGSKLRGRKLRV 72

RNA recognition motif 2 (RRM2) and 4 (RRM4) found in RNA-binding protein MRN1 and similar proteins; This subgroup corresponds to the RRM2 and RRM4 of MRN1, also termed multicopy suppressor of RSC-NHP6 synthetic lethality protein 1, or post-transcriptional regulator of 69 kDa, and is an RNA-binding protein found in yeast. Although its specific biological role remains unclear, MRN1 might be involved in translational regulation. Members in this family contain four copies of conserved RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLDVHKIQNGCKCfAFVDLGSMQKVTLAIQELNGK--LFHKRKLF 101
Cdd:cd12262     6 VYVGNLDDSLTEEEIRGILEKYGEIESIKILKEKNC-AFVNYLNIANAIKAVQELPIKnpKFKKVRIN 72

U2 snRNP auxilliary factor, large subunit, splicing factor; These splicing factors consist of an N-terminal arginine-rich low complexity domain followed by three tandem RNA recognition motifs (pfam00076). The well-characterized members of this family are auxilliary components of the U2 small nuclear ribonuclearprotein splicing factor (U2AF). These proteins are closely related to the CC1-like subfamily of splicing factors (TIGR01622). Members of this subfamily are found in plants, metazoa and fungi.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441  13 KLLGKNGVLEEqkspgfkkrETEVYVGNLPLDISKEEILYLLKDFNPLD----VHKIQNG-CKCFAFVDLGSMQKVTLAI 87
Cdd:TIGR01642 284 KLVNSTTVLDS---------KDRIYIGNLPLYLGEDQIKELLESFGDLKafnlIKDIATGlSKGYAFCEYKDPSVTDVAI 354

                          90
                  ....*....|....*
gi 1331831441  88 QELNGKLFHKRKLFV 102
Cdd:TIGR01642 355 AALNGKDTGDNKLHV 369

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPL---DVhkIQNgckcFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd12343     2 IFVGNLPDAATSEELRALFEKYGKVtecDI--VKN----YAFVHMEKEEDAEDAIKALNGYEFMGSRINV 65

RNA recognition motif 2 (RRM2) found in RNA-binding protein MRN1 and similar proteins; This subgroup corresponds to the RRM2 of MRN1, also termed multicopy suppressor of RSC-NHP6 synthetic lethality protein 1, or post-transcriptional regulator of 69 kDa, which is a RNA-binding protein found in yeast. Although its specific biological role remains unclear, MRN1 might be involved in translational regulation. Members in this family contain four copies of conserved RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLDVHKIQNGcKCFAFVDLGSMQKVTLAIQELN-GKLFHKRKLF 101
Cdd:cd12523     6 VYLGNLPESITEEELREDLEKFGPIDQIKIVKE-KNIAFVHFLSIANAIKVVTTLPlNPKWAKRRIY 71

RNA recognition motif 4 (RRM4) found in RNA-binding protein RBM12, RBM12B and similar proteins; This subfamily corresponds to the RRM4 of RBM12 and RBM12B. RBM12, also termed SH3/WW domain anchor protein in the nucleus (SWAN), is ubiquitously expressed. It contains five distinct RNA binding motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two proline-rich regions, and several putative transmembrane domains. RBM12B show high sequence semilarity with RBM12. It contains five distinct RRMs as well. The biological roles of both RBM12 and RBM12B remain unclear.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKD--FNPLDVHKIQNG---CKCFAFVDLGSMQKVtLAIQELNGKLFHKRKLFV 102
Cdd:cd12514     2 IRITNLPYDATPVDIQRFFEDhgVRPEDVHLLRNKkgrGNGEALVTFKSEGDA-REVLKLNGKKLGKREAVV 72

Tudor domain found in Tudor domain-containing protein 11 (TDRD11) and similar proteins; TDRD11, also called Staphylococcal nuclease domain-containing protein 1 (SND1), 100 kDa coactivator, EBNA2 coactivator p100, or p100 co-activator, is a multifunctional protein that is reportedly associated with different types of RNA molecules, including mRNA, miRNA, pre-miRNA, and dsRNA. It has been implicated in a number of biological processes in eukaryotic cells, including the cell cycle, DNA damage repair, proliferation, and apoptosis. TDRD11 is overexpressed in multiple cancers and functions as an oncogene. It contains multiple Staphylococcal nuclease (SN) domains and a C-terminal Tudor domain. The Tudor domain binds to proteins with dimethylated arginine or lysine residues, and may also bind methylated histone tails to facilitate protein-protein interactions.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1331831441 230 LAQAEEQQPYLEGS-TVTRGTRCLAEYHLGDyghAWNRCWVLD-RVDTWAVVMFIDFGQLATIPVQSLRSLDS 300
Cdd:cd20433    12 LRFEIASNPPLPGSyTPRKGDLCAAKFVEDG---EWYRAKVEKvEGDKKVHVLYIDYGNREVLPSTRLAALPP 81

RNA recognition motif 3 (RRM3) found in the Hu proteins family; This subfamily corresponds to the RRM3 of the Hu proteins family which represent 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. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1331831441  36 VYVGNLPLDISkEEILYLLkdFNP----------LDVHKiqNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd12377     2 IFVYNLAPDAD-ESLLWQL--FGPfgavqnvkiiRDFTT--NKCKGYGFVTMTNYDEAAVAIASLNGYRLGGRVLQV 73

RNA recognition motif 2 (RRM2) found in U2 large nuclear ribonucleoprotein auxiliary factor U2AF 65 kDa subunit (U2AF65) and similar proteins; This subfamily corresponds to the RRM2 of U2AF65 and dU2AF50. U2AF65, also termed U2AF2, is the large subunit of U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF), which has been implicated in the recruitment of U2 snRNP to pre-mRNAs and is a highly conserved heterodimer composed of large and small subunits. U2AF65 specifically recognizes the intron polypyrimidine tract upstream of the 3' splice site and promotes binding of U2 snRNP to the pre-mRNA branchpoint. U2AF65 also plays an important role in the nuclear export of mRNA. It facilitates the formation of a messenger ribonucleoprotein export complex, containing both the NXF1 receptor and the RNA substrate. Moreover, U2AF65 interacts directly and specifically with expanded CAG RNA, and serves as an adaptor to link expanded CAG RNA to NXF1 for RNA export. U2AF65 contains an N-terminal RS domain rich in arginine and serine, followed by a proline-rich segment and three C-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The N-terminal RS domain stabilizes the interaction of U2 snRNP with the branch point (BP) by contacting the branch region, and further promotes base pair interactions between U2 snRNA and the BP. The proline-rich segment mediates protein-protein interactions with the RRM domain of the small U2AF subunit (U2AF35 or U2AF1). The RRM1 and RRM2 are sufficient for specific RNA binding, while RRM3 is responsible for protein-protein interactions. The family also includes Splicing factor U2AF 50 kDa subunit (dU2AF50), the Drosophila ortholog of U2AF65. dU2AF50 functions as an essential pre-mRNA splicing factor in flies. It associates with intronless mRNAs and plays a significant and unexpected role in the nuclear export of a large number of intronless mRNAs.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLD----VHKIQNG-CKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd12231     3 LFIGGLPNYLNEDQVKELLQSFGKLKafnlVKDSATGlSKGYAFCEYVDDNVTDQAIAGLNGMQLGDKKLLV 74

RNA recognition motif 1 (RRM1) found in Schizosaccharomyces pombe mRNA export factor Crp79 and similar proteins; Crp79, also called meiotic expression up-regulated protein 5 (Mug5), or polyadenylate-binding protein crp79, or PABP, or poly(A)-binding protein, is an auxiliary mRNA export factor that binds the poly(A) tail of mRNA and is involved in the export of mRNA from the nucleus to the cytoplasm. 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1331831441  35 EVYVGNLPLDISKEEILYLLKDFN--------PLDVHKIQNGcKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFV 102
Cdd:cd21619     3 TIYVGNIDMTINEDALEKIFSRYGqvesvrrpPIHTDKADRT-TGFGFIKYTDAESAERAMQQADGILLGRRRLVV 77

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNP-LDVHKIQN--GCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVN 103
Cdd:cd12407     3 LHVSNIPFRFRDPDLRQMFGQFGTiLDVEIIFNerGSKGFGFVTFANSADADRAREKLNGTVVEGRKIEVN 73

RNA recognition motif 1 (RRM1) found in plant Mei2-like proteins; This subgroup corresponds to the RRM1 of Mei2-like proteins that represent an ancient eukaryotic RNA-binding proteins family. Their corresponding Mei2-like genes appear to have arisen early in eukaryote evolution, been lost from some lineages such as Saccharomyces cerevisiae and metazoans, and diversified in the plant lineage. The plant Mei2-like genes may function in cell fate specification during development, rather than as stimulators of meiosis. Members in this family contain three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The C-terminal RRM (RRM3) is unique to Mei2-like proteins and it is highly conserved between plants and fungi. Up to date, the intracellular localization, RNA target(s), cellular interactions and phosphorylation states of Mei2-like proteins in plants remain unclear.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1331831441  37 YVGNLPLDISKEEILYLLKDFNplDVHKIQNGCKCFAFV-----DLGSMQKvtlAIQELNGKLFHKRKLFV 102
Cdd:cd12524     5 FVRNINSSVEDEELRALFEQFG--EIRTLYTACKHRGFImvsyyDIRAAQS---AKRALQGTELGGRKLDI 70

RNA recognition motif 1 (RRM1) found in cytoplasmic polyadenylation element-binding protein CPEB-2, CPEB-3, CPEB-4 and similar protiens; This subgroup corresponds to the RRM1 of the paralog proteins CPEB-2, CPEB-3 and CPEB-4, all well-conserved in both, vertebrates and invertebrates. Due to the high sequence similarity, members in this family may share similar expression patterns and functions. CPEB-2 is an RNA-binding protein that is abundantly expressed in testis and localized in cytoplasm in transfected HeLa cells. It preferentially binds to poly(U) RNA oligomers and may regulate the translation of stored mRNAs during spermiogenesis. Moreover, CPEB-2 impedes target RNA translation at elongation; it directly interacts with the elongation factor, eEF2, to reduce eEF2/ribosome-activated GTP hydrolysis in vitro and inhibit peptide elongation of CPEB2-bound RNA in vivo. CPEB-3 is a sequence-specific translational regulatory protein that regulates translation in a polyadenylation-independent manner. It functions as a translational repressor that governs the synthesis of the AMPA receptor GluR2 through binding GluR2 mRNA. It also represses translation of a reporter RNA in transfected neurons and stimulates translation in response to NMDA. CPEB-4 is an RNA-binding protein that mediates meiotic mRNA cytoplasmic polyadenylation and translation. It is essential for neuron survival and present on the endoplasmic reticulum (ER). It is accumulated in the nucleus upon ischemia or the depletion of ER calcium. CPEB-4 is overexpressed in a large variety of tumors and is associated with many mRNAs in cancer cells. All family members contain an N-terminal unstructured region, two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a Zn-finger motif. In addition, they do have conserved nuclear export signals that are not present in CPEB-1.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1331831441  36 VYVGNLPLDISKEEILYLLKDFNPLDV---HKIQNgCKCFA--------FVDLGSMQKVTLAIQELNGKLF 95
Cdd:cd12724     3 VFVGGLPPDIDEDEITASFRRFGPLVVdwpHKAES-KSYFPpkgyafllFQDERSVQALIDACIEEDDKLY 72

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1331831441  37 YVGNLPLDISKEEILYLLKDFNPLDVHKIQNGC----KCFAFVDLGSMQKVTLAIQeLNGKLFHKRKLFVN 103
Cdd:cd12402     6 YLGNLPYDVTEDDIEDFFRGLNISSVRLPRENGpgrlRGFGYVEFEDRESLIQALS-LNEESLKNRRIRVD 75

RNA recognition motif 4 (RRM4) found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM4 of type I poly(A)-binding proteins (PABPs), highly conserved proteins that bind to the poly(A) tail present at the 3' ends of most eukaryotic mRNAs. They have been implicated in theThe CD corresponds to the RRM. regulation of poly(A) tail length during the polyadenylation reaction, translation initiation, mRNA stabilization by influencing the rate of deadenylation and inhibition of mRNA decapping. The family represents type I polyadenylate-binding proteins (PABPs), including polyadenylate-binding protein 1 (PABP-1 or PABPC1), polyadenylate-binding protein 3 (PABP-3 or PABPC3), polyadenylate-binding protein 4 (PABP-4 or APP-1 or iPABP), polyadenylate-binding protein 5 (PABP-5 or PABPC5), polyadenylate-binding protein 1-like (PABP-1-like or PABPC1L), polyadenylate-binding protein 1-like 2 (PABPC1L2 or RBM32), polyadenylate-binding protein 4-like (PABP-4-like or PABPC4L), yeast polyadenylate-binding protein, cytoplasmic and nuclear (PABP or ACBP-67), and similar proteins. PABP-1 is an ubiquitously expressed multifunctional protein that may play a role in 3' end formation of mRNA, translation initiation, mRNA stabilization, protection of poly(A) from nuclease activity, mRNA deadenylation, inhibition of mRNA decapping, and mRNP maturation. Although PABP-1 is thought to be a cytoplasmic protein, it is also found in the nucleus. PABP-1 may be involved in nucleocytoplasmic trafficking and utilization of mRNP particles. PABP-1 contains four copies of RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), a less well conserved linker region, and a proline-rich C-terminal conserved domain (CTD). PABP-3 is a testis-specific poly(A)-binding protein specifically expressed in round spermatids. It is mainly found in mammalian and may play an important role in the testis-specific regulation of mRNA homeostasis. PABP-3 shows significant sequence similarity to PABP-1. However, it binds to poly(A) with a lower affinity than PABP-1. Moreover, PABP-1 possesses an A-rich sequence in its 5'-UTR and allows binding of PABP and blockage of translation of its own mRNA. In contrast, PABP-3 lacks the A-rich sequence in its 5'-UTR. PABP-4 is an inducible poly(A)-binding protein (iPABP) that is primarily localized to the cytoplasm. It shows significant sequence similarity to PABP-1 as well. The RNA binding properties of PABP-1 and PABP-4 appear to be identical. PABP-5 is encoded by PABPC5 gene within the X-specific subinterval, and expressed in fetal brain and in a range of adult tissues in mammalian, such as ovary and testis. It may play an important role in germ cell development. Moreover, unlike other PABPs, PABP-5 contains only four RRMs, but lacks both the linker region and the CTD. PABP-1-like and PABP-1-like 2 are the orthologs of PABP-1. PABP-4-like is the ortholog of PABP-5. Their cellular functions remain unclear. The family also includes the yeast PABP, a conserved poly(A) binding protein containing poly(A) tails that can be attached to the 3'-ends of mRNAs. The yeast PABP and its homologs may play important roles in the initiation of translation and in mRNA decay. Like vertebrate PABP-1, the yeast PABP contains four RRMs, a linker region, and a proline-rich CTD as well. The first two RRMs are mainly responsible for specific binding to poly(A). The proline-rich region may be involved in protein-protein interactions.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1331831441  37 YVGNLPLDISKEEilyLLKDFNP------LDVHKIQNG-CKCFAFVDLGSMQKVTLAIQELNGKLFHKRKLFVNTSKR 107
Cdd:cd12381     5 YVKNLDDTIDDEK---LREEFSPfgtitsAKVMTDEGGrSKGFGFVCFSSPEEATKAVTEMNGRIIGGKPLYVALAQR 79

RNA recognition motif (RRM) found in RNA-binding protein 7 (RBM7) and similar proteins; This subfamily corresponds to the RRM of RBM7, RBM11 and their eukaryotic homologous. RBM7 is an ubiquitously expressed pre-mRNA splicing factor that enhances messenger RNA (mRNA) splicing in a cell-specific manner or in a certain developmental process, such as spermatogenesis. It interacts with splicing factors SAP145 (the spliceosomal splicing factor 3b subunit 2) and SRp20, and may play a more specific role in meiosis entry and progression. Together with additional testis-specific RNA-binding proteins, RBM7 may regulate the splicing of specific pre-mRNA species that are important in the meiotic cell cycle. RBM11 is a novel tissue-specific splicing regulator that is selectively expressed in brain, cerebellum and testis, and to a lower extent in kidney. It is localized in the nucleoplasm and enriched in SRSF2-containing splicing speckles. It may play a role in the modulation of alternative splicing during neuron and germ cell differentiation. Both, RBM7 and RBM11, contain an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a region lacking known homology at the C-terminus. The RRM is responsible for RNA binding, whereas the C-terminal region permits nuclear localization and homodimerization.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1331831441  36 VYVGNLPLDISkEEILY-LLKDFNPLDVHKI----QNGCKCFAFVDLGSMQKVTLAIQELNGKLFHKRKL 100
Cdd:cd12336     4 LFVGNLDPRVT-EEILYeLFLQAGPLEGVKIpkdpNGKPKNFAFVTFKHEVSVPYAIQLLNGIRLFGREI 72