zinc finger;

                           10        20
                   ....*....|....*....|....*..
gi 8922328     159 RNRPHICSFWVKGECKRGEECPYRHEK 185
Cdd:smart00356   1 KYKTELCKFFKRGYCPRGDRCKFAHPL 27

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328     233 TLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEvAAEKSFNKLIVNGRRLNV 300
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDKEtgkskgFAFVEFESEEDAE-KALEALNGKELDGRPLKV 73

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 8922328    234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ-----CAFIQFATRQAAEvAAEKSFNKLIVNGRRL 298
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLVRDETgrskgFAFVEFEDEEDAE-KAIEALNGKELGGREL 69

zinc finger;

                           10        20
                   ....*....|....*....|....*..
gi 8922328     159 RNRPHICSFWVKGECKRGEECPYRHEK 185
Cdd:smart00356   1 KYKTELCKFFKRGYCPRGDRCKFAHPL 27

glycine-rich RNA-binding protein 4; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 8922328   232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEvAAEKSFNKLIVNGR--RLNVKWG 303
Cdd:PLN03134  35 TKLFIGGLSWGTDDASLRDAFAHFGDVVDAKVIVDRETgrsrgfGFVNFNDEGAAT-AAISEMDGKELNGRhiRVNPAND 113

                         90
                 ....*....|....*....
gi 8922328   304 RSQAARGKEKEKDGTTDSG 322
Cdd:PLN03134 114 RPSAPRAYGGGGGYSGGGG 132

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328     233 TLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEvAAEKSFNKLIVNGRRLNV 300
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDKEtgkskgFAFVEFESEEDAE-KALEALNGKELDGRPLKV 73

RNA recognition motif 3 (RRM3) found in yeast negative growth regulatory protein NGR1 (RBP1), yeast protein NAM8 and similar proteins; This subfamily corresponds to the RRM3 of NGR1 and NAM8. NGR1, also termed RNA-binding protein RBP1, is a putative glucose-repressible protein that binds both RNA and single-stranded DNA (ssDNA) in yeast. It may function in regulating cell growth in early log phase, possibly through its participation in RNA metabolism. NGR1 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a glutamine-rich stretch that may be involved in transcriptional activity. In addition, NGR1 has an asparagine-rich region near the carboxyl terminus which also harbors a methionine-rich region. The family also includes protein NAM8, which is a putative RNA-binding protein that acts as a suppressor of mitochondrial splicing deficiencies when overexpressed in yeast. It may be a non-essential component of the mitochondrial splicing machinery. Like NGR1, NAM8 contains two RRMs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEKsFNKLIVNGRRLNVKWG 303
Cdd:cd12346   2 TTVFVGGLDPNVTEEDLRVLFGPFGEIVYVKIPPGKGCGFVQFVNRASAEAAIQK-LQGTPIGGSRIRLSWG 72

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        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAeKSFNKLIVNGRRLNVKWG 303
Cdd:cd12354   1 TTVYVGNITKGLTEALLQQTFSPFGQILEVRVFPDKGYAFIRFDSHEAATHAI-VSVNGTIINGQAVKCSWG 71

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 8922328  233 TLYVGGLGDTITETDLRNHFYQFGEIRTITVV------QRQQCAFIQFATRQAAEVAAEKsFNKLIVNGRRLNVKWGRSQ 306
Cdd:COG0724   3 KIYVGNLPYSVTEEDLRELFSEYGEVTSVKLItdretgRSRGFGFVEMPDDEEAQAAIEA-LNGAELMGRTLKVNEARPR 81

                ....
gi 8922328  307 AARG 310
Cdd:COG0724  82 EERP 85

RNA recognition motif (RRM) found in U2-associated protein SR140 and similar proteins; This subgroup corresponds to the RRM of SR140 (also termed U2 snRNP-associated SURP motif-containing protein orU2SURP, or 140 kDa Ser/Arg-rich domain protein) which is a putative splicing factor mainly found in higher eukaryotes. Although it is initially identified as one of the 17S U2 snRNP-associated proteins, the molecular and physiological function of SR140 remains unclear. SR140 contains an N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a SWAP/SURP domain that is found in a number of pre-mRNA splicing factors in the middle region, and a C-terminal arginine/serine-rich domain (RS domain).

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEI--------RTITVVQRQQ-CAFIQFATRQAAEVAAEKsFNKLIVNGRRLNVKW 302
Cdd:cd12223   2 TNLYVGNLPPSVTEEVLLREFGRFGPLasvkimwpRTEEERRRNRnCGFVAFMSRADAERAMRE-LNGKDVMGYELKLGW 80

                ...
gi 8922328  303 GRS 305
Cdd:cd12223  81 GKA 83

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAeKSFNKLIVNGRRLNVK 301
Cdd:cd12417   2 LWISGLSDTTKAADLKKIFSKYGKVVSAKVVTSARtpgsrcYGYVTMASVEEADLCI-KSLNKTELHGRVITVE 74

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEKSfnKLIVNGRRLNV 300
Cdd:cd12384   1 TKIFVGGLPYHTTDDSLREYFEQFGEIEEAVVITDRQTgksrgyGFVTMADREAAERACKDP--NPIIDGRKANV 73

RNA recognition motif 1 (RRM1) found in the p54nrb/PSF/PSP1 family; This subfamily corresponds to the RRM1 of the p54nrb/PSF/PSP1 family, including 54 kDa nuclear RNA- and DNA-binding protein (p54nrb or NonO or NMT55), polypyrimidine tract-binding protein (PTB)-associated-splicing factor (PSF or POMp100), paraspeckle protein 1 (PSP1 or PSPC1), which are ubiquitously expressed and are conserved in vertebrates. p54nrb is a multi-functional protein involved in numerous nuclear processes including transcriptional regulation, splicing, DNA unwinding, nuclear retention of hyperedited double-stranded RNA, viral RNA processing, control of cell proliferation, and circadian rhythm maintenance. PSF is also a multi-functional protein that binds RNA, single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) and many factors, and mediates diverse activities in the cell. PSP1 is a novel nucleolar factor that accumulates within a new nucleoplasmic compartment, termed paraspeckles, and diffusely distributes in the nucleoplasm. The cellular function of PSP1 remains unknown currently. This subfamily also includes some p54nrb/PSF/PSP1 homologs from invertebrate species, such as the Drosophila melanogaster gene no-ontransient A (nonA) encoding puff-specific protein Bj6 (also termed NONA) and Chironomus tentans hrp65 gene encoding protein Hrp65. D. melanogaster NONA is involved in eye development and behavior, and may play a role in circadian rhythm maintenance, similar to vertebrate p54nrb. C. tentans Hrp65 is a component of nuclear fibers associated with ribonucleoprotein particles in transit from the gene to the nuclear pore. All family members contain a DBHS domain (for Drosophila behavior, human splicing), which comprises two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a charged protein-protein interaction module. PSF has an additional large N-terminal domain that differentiates it from other family members.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEvAAEKSFNKLIVNGRRLNVK 301
Cdd:cd12332   4 LFVGNLPNDITEEEFKELFQKYGEVSEVFLNKGKGFGFIRLDTRANAE-AAKAELDGTPRKGRQLRVR 70

RNA recognition motif (RRM) found in nucleolar protein 8 (NOL8) and similar proteins; This model corresponds to the RRM of NOL8 (also termed Nop132) encoded by a novel NOL8 gene that is up-regulated in the majority of diffuse-type, but not intestinal-type, gastric cancers. Thus, NOL8 may be a good molecular target for treatment of diffuse-type gastric cancer. Also, NOL8 is a phosphorylated protein that contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), suggesting NOL8 is likely to function as a novel RNA-binding protein. It may be involved in regulation of gene expression at the post-transcriptional level or in ribosome biogenesis in cancer cells.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC-----AFIQFATRQAAEVAAEKSFNKLIVNGRRLNVKWGR 304
Cdd:cd12226   2 LFVGGLSPSITEDDLERRFSRFGTVSDVEIIRKKDApdrgfAYIDLRTSEAALQKCLSTLNGVKWKGSRLKIQLAK 77

RNA recognition motif 2 (RRM2) found in yeast nuclear polyadenylated RNA-binding protein 4 (Hrp1p or Nab4p) and similar proteins; This subfamily corresponds to the RRM1 of Hrp1p and similar proteins. Hrp1p or Nab4p, also termed cleavage factor IB (CFIB), is a sequence-specific trans-acting factor that is essential for mRNA 3'-end formation in yeast Saccharomyces cerevisiae. It can be UV cross-linked to RNA and specifically recognizes the (UA)6 RNA element required for both, the cleavage and poly(A) addition steps. Moreover, Hrp1p can shuttle between the nucleus and the cytoplasm, and play an additional role in the export of mRNAs to the cytoplasm. Hrp1p also interacts with Rna15p and Rna14p, two components of CF1A. In addition, Hrp1p functions as a factor directly involved in modulating the activity of the nonsense-mediated mRNA decay (NMD) pathway; it binds specifically to a downstream sequence element (DSE)-containing RNA and interacts with Upf1p, a component of the surveillance complex, further triggering the NMD pathway. Hrp1p contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an arginine-glycine-rich region harboring repeats of the sequence RGGF/Y.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEKSFNKLivNGRRLNVK 301
Cdd:cd12330   2 IFVGGLAPDVTEEEFKEYFEQFGTVVDAVVMLDHDTgrsrgfGFVTFDSESAVEKVLSKGFHEL--GGKKVEVK 73

RNA recognition motif 1 (RRM1) found in vertebrate RNA-binding protein 26 (RBM26) and similar proteins; This subfamily corresponds to the RRM1 of RBM26, and the RRM of RBM27. RBM26, also known as cutaneous T-cell lymphoma (CTCL) tumor antigen se70-2, represents a cutaneous lymphoma (CL)-associated antigen. It contains two RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The RRMs may play some functional roles in RNA-binding or protein-protein interactions. RBM27 contains only one RRM; its biological function remains unclear.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 8922328  244 TETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEvAAEKSfNKLIVNGRRLNVKW 302
Cdd:cd12257  15 NITKLREHFSKFGTIVNIQVNYNPESALVQFSTSEEAN-KAYRS-PEAVFNNRFIKVFW 71

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        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAEKSFNKLIVNG--RRLNVK 301
Cdd:cd12361   2 LFVGMIPKTASEEDVRPLFEQFGNIEEVQILRDKQtgqskgCAFVTFSTREEALRAIEALHNKKTMPGcsSPLQVK 77

RNA recognition motif (RRM) found in AZoospermia (DAZ) autosomal homologs, DAZL (DAZ-like) and BOULE; This subfamily corresponds to the RRM domain of two Deleted in AZoospermia (DAZ) autosomal homologs, DAZL (DAZ-like) and BOULE. BOULE is the founder member of the family and DAZL arose from BOULE in an ancestor of vertebrates. The DAZ gene subsequently originated from a duplication transposition of the DAZL gene. Invertebrates contain a single DAZ homolog, BOULE, while vertebrates, other than catarrhine primates, possess both BOULE and DAZL genes. The catarrhine primates possess BOULE, DAZL, and DAZ genes. The family members encode closely related RNA-binding proteins that are required for fertility in numerous organisms. These proteins contain an RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a varying number of copies of a DAZ motif, believed to mediate protein-protein interactions. DAZL and BOULE contain a single copy of the DAZ motif, while DAZ proteins can contain 8-24 copies of this repeat. Although their specific biochemical functions remain to be investigated, DAZL proteins may interact with poly(A)-binding proteins (PABPs), and act as translational activators of specific mRNAs during gametogenesis.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 8922328  233 TLYVGGLGDTITETDLRNHFYQFGEIRTITVVQ-RQQC----AFIQFATRQAAEvAAEKSFNKLIVNGRRLNV 300
Cdd:cd12412   4 RIFVGGIDWDTTEEELREFFSKFGKVKDVKIIKdRAGVskgyGFVTFETQEDAE-KIQKWGANLVFKGKKLNV 75

RNA recognition motif (RRM) found in SR-related and CTD-associated factor 4 (SCAF4) and similar proteins; The CD corresponds to the RRM of SCAF4 (also termed splicing factor, arginine/serine-rich 15 or SFR15, or CTD-binding SR-like protein RA4) that belongs to a new class of SCAFs (SR-like CTD-associated factors). Although its biological function remains unclear, SCAF4 shows high sequence similarity to SCAF8 that interacts specifically with a highly serine-phosphorylated form of the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II (pol II) and may play a direct role in coupling with both, transcription and pre-mRNA processing, processes. SCAF4 and SCAF8 both contain a conserved N-terminal CTD-interacting domain (CID), an atypical RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and serine/arginine-rich motifs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEK-SFNKLIVNGRRLNVKW 302
Cdd:cd12461   5 TTLWVGQLDKRTTQQDVASLLEEFGQIESINMIPPRGCAYIVMVHRQDAYRALQKlSRGNYKVNQKSIKIAW 76

RNA recognition motif (RRM) found in SR-related and CTD-associated factor 8 (SCAF8) and similar proteins; This subgroup corresponds to the RRM of SCAF8 (also termed CDC5L complex-associated protein 7, or RNA-binding motif protein 16, or CTD-binding SR-like protein RA8), a nuclear matrix protein that interacts specifically with a highly serine-phosphorylated form of the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II (pol II). The pol II CTD plays a role in coupling transcription and pre-mRNA processing. SCAF8 co-localizes primarily with transcription sites that are enriched in nuclear matrix fraction, which is known to contain proteins involved in pre-mRNA processing. Thus, SCAF8 may play a direct role in coupling with both, transcription and pre-mRNA processing, processes. SCAF8, together with SCAF4, represents a new class of SCAFs (SR-like CTD-associated factors). They contain a conserved N-terminal CTD-interacting domain (CID), an atypical RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and serine/arginine-rich motifs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEK-SFNKLIVNGRRLNVKWG 303
Cdd:cd12462   3 TTLWVGQVDKKATQQDLTNLFEEFGQIESINMIPPRGCAYVCMVHRQDAYRALQKlSTGSFKIGSKIIKIAWA 75

RNA recognition motif 3 (RRM3) found in the Spen (split end) protein family; This subfamily corresponds to the RRM3 domain in the Spen (split end) protein family which includes RNA binding motif protein 15 (RBM15), putative RNA binding motif protein 15B (RBM15B) and similar proteins found in Metazoa. RBM15, also termed one-twenty two protein 1 (OTT1), conserved in eukaryotes, is a novel mRNA export factor and is a novel component of the NXF1 pathway. It binds to NXF1 and serves as receptor for the RNA export element RTE. It also possess mRNA export activity and can facilitate the access of DEAD-box protein DBP5 to mRNA at the nuclear pore complex (NPC). RNA-binding protein 15B (RBM15B), also termed one twenty-two 3 (OTT3), is a paralog of RBM15 and therefore has post-transcriptional regulatory activity. It is a nuclear protein sharing with RBM15 the association with the splicing factor compartment and the nuclear envelope as well as the binding to mRNA export factors NXF1 and Aly/REF. Members in this family belong to the Spen (split end) protein family, which shares a domain architecture comprising of three N-terminal RNA recognition motifs (RRMs), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal SPOC (Spen paralog and ortholog C-terminal) domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAE--KSFnKLIVNGRRLNV 300
Cdd:cd12310   1 LWVGGLGPWTSLAELEREFDRFGAIRKIDYRKGDDYAYILYESLDAAQAAVRalRGF-PLGGPDRRLRV 68

RNA recognition motif 3 (RRM3) found in SMART/HDAC1-associated repressor protein (SHARP) and similar proteins; This subfamily corresponds to the RRM3 of SHARP, also termed Msx2-interacting protein (MINT), or SPEN homolog, an estrogen-inducible transcriptional repressor that interacts directly with the nuclear receptor corepressor SMRT, histone deacetylases (HDACs) and components of the NuRD complex. SHARP recruits HDAC activity and binds to the steroid receptor RNA coactivator SRA through four conserved N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), further suppressing SRA-potentiated steroid receptor transcription activity. Thus, SHARP has the capacity to modulate both liganded and nonliganded nuclear receptors. SHARP also has been identified as a component of transcriptional repression complexes in Notch/RBP-Jkappa signaling pathways. In addition to the N-terminal RRMs, SHARP possesses a C-terminal SPOC domain (Spen paralog and ortholog C-terminal domain), which is highly conserved among Spen proteins.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 8922328  233 TLYVGGLGDTITETDLRNHFYQFGEIRTITvVQRQ----QCAFIQFATRQAAeVAAEKSFNKLIVNGRRLNV 300
Cdd:cd12350   4 TLFIGNLEKTTTYGDLRNIFERFGEIIDID-IKKQngnpQYAFLQYCDIASV-VKAIKKMDGEYLGNNRLKL 73

RNA recognition motif 3 (RRM3) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM3 of RBM28 and Nop4p. RBM28 is a specific nucleolar component of the spliceosomal small nuclear ribonucleoproteins (snRNPs), possibly coordinating their transition through the nucleolus. It specifically associates with U1, U2, U4, U5, and U6 small nuclear RNAs (snRNAs), and may play a role in the maturation of both small nuclear and ribosomal RNAs. RBM28 has four RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and an extremely acidic region between RRM2 and RRM3. The family also includes nucleolar protein 4 (Nop4p or Nop77p) encoded by YPL043W from Saccharomyces cerevisiae. It is an essential nucleolar protein involved in processing and maturation of 27S pre-rRNA and biogenesis of 60S ribosomal subunits. Nop4p also contains four RRMs.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 8922328  244 TETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAEKSFNK-----LIVNGRRLNV 300
Cdd:cd12415  13 TEEDLKEFFSKFGEVKYARIVLDKDtghskgTAFVQFKTKESADKCIEAANDEsedggLVLDGRKLIV 80

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein A subfamily; This subfamily corresponds to the RRM2 of hnRNP A0, hnRNP A1, hnRNP A2/B1, hnRNP A3 and similar proteins. hnRNP A0 is a low abundance hnRNP protein that has been implicated in mRNA stability in mammalian cells. It has been identified as the substrate for MAPKAP-K2 and may be involved in the lipopolysaccharide (LPS)-induced post-transcriptional regulation of tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase 2 (COX-2) and macrophage inflammatory protein 2 (MIP-2). hnRNP A1 is an abundant eukaryotic nuclear RNA-binding protein that may modulate splice site selection in pre-mRNA splicing. hnRNP A2/B1 is an RNA trafficking response element-binding protein that interacts with the hnRNP A2 response element (A2RE). Many mRNAs, such as myelin basic protein (MBP), myelin-associated oligodendrocytic basic protein (MOBP), carboxyanhydrase II (CAII), microtubule-associated protein tau, and amyloid precursor protein (APP) are trafficked by hnRNP A2/B1. hnRNP A3 is also a RNA trafficking response element-binding protein that participates in the trafficking of A2RE-containing RNA. The hnRNP A subfamily is characterized by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a long glycine-rich region at the C-terminus.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEKSFNklIVNGRRLNVK 301
Cdd:cd12328   2 LFVGGLKEDVEEEDLREYFSQFGKVESVEIVTDKETgkkrgfAFVTFDDHDSVDKIVLQKYH--TINGHRCEVK 73

RNA recognition motif 1 (RRM1) found in heterogeneous nuclear ribonucleoprotein hnRNP A and hnRNP D subfamilies and similar proteins; This subfamily corresponds to the RRM1 in the hnRNP A subfamily which includes hnRNP A0, hnRNP A1, hnRNP A2/B1, hnRNP A3 and similar proteins. hnRNP A0 is a low abundance hnRNP protein that has been implicated in mRNA stability in mammalian cells. hnRNP A1 is an abundant eukaryotic nuclear RNA-binding protein that may modulate splice site selection in pre-mRNA splicing. hnRNP A2/B1 is an RNA trafficking response element-binding protein that interacts with the hnRNP A2 response element (A2RE). hnRNP A3 is also a RNA trafficking response element-binding protein that participates in the trafficking of A2RE-containing RNA. The hnRNP A subfamily is characterized by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), followed by a long glycine-rich region at the C-terminus. The hnRNP D subfamily includes hnRNP D0, hnRNP A/B, hnRNP DL and similar proteins. hnRNP D0 is a UUAG-specific nuclear RNA binding protein that may be involved in pre-mRNA splicing and telomere elongation. hnRNP A/B is an RNA unwinding protein with a high affinity for G- followed by U-rich regions. hnRNP A/B has also been identified as an APOBEC1-binding protein that interacts with apolipoprotein B (apoB) mRNA transcripts around the editing site and thus, plays an important role in apoB mRNA editing. hnRNP DL (or hnRNP D-like) is a dual functional protein that possesses DNA- and RNA-binding properties. It has been implicated in mRNA biogenesis at the transcriptional and post-transcriptional levels. All members in this subfamily contain two putative RRMs and a glycine- and tyrosine-rich C-terminus. The family also contains DAZAP1 (Deleted in azoospermia-associated protein 1), RNA-binding protein Musashi homolog Musashi-1, Musashi-2 and similar proteins. They all harbor two RRMs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEKSFNKLivNGRRLNVK 301
Cdd:cd12325   1 LFVGGLSWETTEESLREYFSKYGEVVDCVVMKDPATgrsrgfGFVTFKDPSSVDAVLAARPHTL--DGRTIDPK 72

RNA recognition motif 3 (RRM3) found in nucleolysin TIAR and similar proteins; This subgroup corresponds to the RRM3 of nucleolysin TIAR, also termed TIA-1-related protein, a cytotoxic granule-associated RNA-binding protein that shows high sequence similarity with 40-kDa isoform of T-cell-restricted intracellular antigen-1 (p40-TIA-1). TIAR is mainly localized in the nucleus of hematopoietic and nonhematopoietic cells. It is translocated from the nucleus to the cytoplasm in response to exogenous triggers of apoptosis. TIAR possesses nucleolytic activity against cytolytic lymphocyte (CTL) target cells. It can trigger DNA fragmentation in permeabilized thymocytes, and thus may function as an effector responsible for inducing apoptosis. TIAR is composed of three N-terminal highly homologous RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a glutamine-rich C-terminal auxiliary domain containing a lysosome-targeting motif. It interacts with RNAs containing short stretches of uridylates and its RRM2 can mediate the specific binding to uridylate-rich RNAs.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 8922328  233 TLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAeVAAEKSFNKLIVNGRRLNVKWGR 304
Cdd:cd12620   2 TVYCGGIASGLTEQLMRQTFSPFGQIMEIRVFPEKGYSFVRFSTHESA-AHAIVSVNGTTIEGHVVKCYWGK 72

polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 8922328    209 VADKLLKRASTMPRLD--PPEDKTITTLYVGGLGDTITETDLRNHFYQFGEIRTITVV--QRQQC---AFIQFATRQAAE 281
Cdd:TIGR01628 154 LNDKEVYVGRFIKKHEreAAPLKKFTNLYVKNLDPSVNEDKLRELFAKFGEITSAAVMkdGSGRSrgfAFVNFEKHEDAA 233

                          90       100       110
                  ....*....|....*....|....*....|....*..
gi 8922328    282 VAAEKSFNK---LIVNGRRLNVKWGRSQAARGKEKEK 315
Cdd:TIGR01628 234 KAVEEMNGKkigLAKEGKKLYVGRAQKRAEREAELRR 270

RNA recognition motif (RRM) found in Zinc finger CCHC-type and RNA-binding motif-containing protein 1 (ZCRB1) and similar proteins; This subfamily corresponds to the RRM of ZCRB1, also termed MADP-1, or U11/U12 small nuclear ribonucleoprotein 31 kDa protein (U11/U12 snRNP 31 or U11/U12-31K), a novel multi-functional nuclear factor, which may be involved in morphine dependence, cold/heat stress, and hepatocarcinoma. It is located in the nucleoplasm, but outside the nucleolus. ZCRB1 is one of the components of U11/U12 snRNPs that bind to U12-type pre-mRNAs and form a di-snRNP complex, simultaneously recognizing the 5' splice site and branchpoint sequence. ZCRB1 is characterized by an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a CCHC-type Zinc finger motif. In addition, it contains core nucleocapsid motifs, and Lys- and Glu-rich domains.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAeKSFNKLIVNGRRLNV 300
Cdd:cd12393   2 STVYVSNLPFSLTNNDLHQIFSKYGKVVKVTILKDKEtrkskgVAFVLFLDRESAHNAV-RAMNNKELFGRTLKC 75

RNA recognition motif 1 (RRM1) found in yeast multiple RNA-binding domain-containing protein 1 (MRD1) and similar proteins; This subgroup corresponds to the RRM1 of MRD1 which is encoded by a novel yeast gene MRD1 (multiple RNA-binding domain). It is well-conserved in yeast and its homologs exist in all eukaryotes. MRD1 is present in the nucleolus and the nucleoplasm. It interacts with the 35 S precursor rRNA (pre-rRNA) and U3 small nucleolar RNAs (snoRNAs). MRD1 is essential for the initial processing at the A0-A2 cleavage sites in the 35 S pre-rRNA. It contains 5 conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), which may play an important structural role in organizing specific rRNA processing events.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEI------RTITVVQRqQCAFIQFATRQAAEvAAEKSFNKLIVNGRRLNV 300
Cdd:cd12565   1 SRIIVKNLPKYVTEKRLKEHFSKKGEItdvkvmRTKDGKSR-RFGFIGFKSEEEAQ-KAVKYFNKTFIDTSKISV 73

RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein RBM23, RBM39 and similar proteins; This subfamily corresponds to the RRM2 of RBM39 (also termed HCC1), a nuclear autoantigen that contains an N-terminal arginine/serine rich (RS) motif and three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). An octapeptide sequence called the RS-ERK motif is repeated six times in the RS region of RBM39. Although the cellular function of RBM23 remains unclear, it shows high sequence homology to RBM39 and contains two RRMs. It may possibly function as a pre-mRNA splicing factor.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEKsFNKLIVNGRRLNVK 301
Cdd:cd12284   1 LYVGSLHFNITEDMLRGIFEPFGKIEFVQLQKDPETgrskgyGFIQFRDAEDAKKALEQ-LNGFELAGRPMKVG 73

RNA recognition motif (RRM) found in transformer-2 protein homolog TRA2-alpha, TRA2-beta and similar proteins; This subfamily corresponds to the RRM of two mammalian homologs of Drosophila transformer-2 (Tra2), TRA2-alpha, TRA2-beta (also termed SFRS10), and similar proteins found in eukaryotes. TRA2-alpha is a 40-kDa serine/arginine-rich (SR) protein that specifically binds to gonadotropin-releasing hormone (GnRH) exonic splicing enhancer on exon 4 (ESE4) and is necessary for enhanced GnRH pre-mRNA splicing. It strongly stimulates GnRH intron A excision in a dose-dependent manner. In addition, TRA2-alpha can interact with either 9G8 or SRp30c, which may also be crucial for ESE-dependent GnRH pre-mRNA splicing. TRA2-beta is a serine/arginine-rich (SR) protein that controls the pre-mRNA alternative splicing of the calcitonin/calcitonin gene-related peptide (CGRP), the survival motor neuron 1 (SMN1) protein and the tau protein. Both, TRA2-alpha and TRA2-beta, contains a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), flanked by the N- and C-terminal arginine/serine (RS)-rich regions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAeVAAEKSFNKLIVNGRRLNV 300
Cdd:cd12363   4 LGVFGLSLYTTERDLREVFSRYGPIEKVQVVYDQQTgrsrgfGFVYFESVEDA-KEAKERLNGQEIDGRRIRV 75

RNA recognition motif 2 (RRM2) found in vertebrate RNA-binding protein 26 (RBM26) and similar proteins; This subfamily corresponds to the RRM2 of RBM26, also known as cutaneous T-cell lymphoma (CTCL) tumor antigen se70-2, which represents a cutaneous lymphoma (CL)-associated antigen. RBM26 contains two RNA recognition motifs (RRMs), also known as RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The RRMs may play some functional roles in RNA-binding or protein-protein interactions.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 8922328  247 DLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEKSfnkLIVNGRRLNVKW 302
Cdd:cd12258  20 DLLPHFAQFGEVEDVQVDEEGLHLIITFKTRKEAEIAAVHG---ARFKGQSLQLAW 72

RNA recognition motif (RRM) found in 80 kDa MCM3-associated protein (Map80) and similar proteins; This subfamily corresponds to the RRM of Map80, also termed germinal center-associated nuclear protein (GANP), involved in the nuclear localization pathway of MCM3, a protein necessary for the initiation of DNA replication and also involves in controls that ensure DNA replication is initiated once per cell cycle. Map80 contains one RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 8922328  248 LRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEKSfNKLIVNGRRLNVKWGR 304
Cdd:cd12443  18 LRRHFSKFGKVARVFCNPRKNLAIVHFKDHESAALAKKKG-KLLSKGGKPIEIFWSS 73

RNA recognition motif 1 (RRM1) found in Arabidopsis thaliana phragmoplastin interacting protein 1 (PHIP1) and similar proteins; This subfamily corresponds to the RRM1 of PHIP1. A. thaliana PHIP1 and its homologs represent a novel class of plant-specific RNA-binding proteins that may play a unique role in the polarized mRNA transport to the vicinity of the cell plate. The family members consist of multiple functional domains, including a lysine-rich domain (KRD domain) that contains three nuclear localization motifs (KKKR/NK), two RNA recognition motifs (RRMs), and three CCHC-type zinc fingers. PHIP1 is a peripheral membrane protein and is localized at the cell plate during cytokinesis in plants. In addition to phragmoplastin, PHIP1 interacts with two Arabidopsis small GTP-binding proteins, Rop1 and Ran2. However, PHIP1 interacted only with the GTP-bound form of Rop1 but not the GDP-bound form. It also binds specifically to Ran2 mRNA.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQC------AFIQFATRQAAEVAAEksFNKLIVNGRRLNVK 301
Cdd:cd12271   1 VYVGGIPYYSTEAEIRSYFSSCGEVRSVDLMRFPDSgnfrgiAFITFKTEEAAKRALA--LDGEMLGNRFLKVE 72

RNA recognition motif 2 (RRM2) found in the Hu proteins family; This subfamily corresponds to the RRM2 of 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. Moreover, HuR has an anti-apoptotic function during early cell stress response. It binds to mRNAs and enhances the expression of several anti-apoptotic proteins, such as p21waf1, p53, and prothymosin alpha. HuR also has pro-apoptotic function by promoting apoptosis when cell death is unavoidable. Furthermore, HuR may be important in muscle differentiation, adipogenesis, suppression of inflammatory response and modulation of gene expression in response to chronic ethanol exposure and amino acid starvation. Hu proteins perform their cytoplasmic and nuclear molecular functions by coordinately regulating functionally related mRNAs. In the cytoplasm, Hu proteins recognize and bind to AU-rich RNA elements (AREs) in the 3' untranslated regions (UTRs) of certain target mRNAs, such as GAP-43, vascular epithelial growth factor (VEGF), the glucose transporter GLUT1, eotaxin and c-fos, and stabilize those ARE-containing mRNAs. They also bind and regulate the translation of some target mRNAs, such as neurofilament M, GLUT1, and p27. In the nucleus, Hu proteins function as regulators of polyadenylation and alternative splicing. Each Hu protein contains three RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). RRM1 and RRM2 may cooperate in binding to an ARE. RRM3 may help to maintain the stability of the RNA-protein complex, and might also bind to poly(A) tails or be involved in protein-protein interactions.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAeKSFNKLIVNG--RRLNVK 301
Cdd:cd12652   3 LYVSGLPKTMTQKELEQLFSQFGRIITSRILCDNVtglsrgVGFIRFDKRVEAERAI-KALNGTIPPGatEPITVK 77

polyadenylate binding protein, human types 1, 2, 3, 4 family; These eukaryotic proteins recognize the poly-A of mRNA and consists of four tandem RNA recognition domains at the N-terminus (rrm: pfam00076) followed by a PABP-specific domain (pfam00658) at the C-terminus. The protein is involved in the transport of mRNA's from the nucleus to the cytoplasm. There are four paralogs in Homo sapiens which are expressed in testis, platelets, broadly expressed and of unknown tissue range.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 8922328    233 TLYVGGLGDTITETDLRNHFYQFGEIRTITV-----VQRQQC-AFIQFATRQAAEVAAEKSFNKLIvNGRRLNVKWgrSQ 306
Cdd:TIGR01628   2 SLYVGDLDPDVTEAKLYDLFKPFGPVLSVRVcrdsvTRRSLGyGYVNFQNPADAERALETMNFKRL-GGKPIRIMW--SQ 78

                          90
                  ....*....|....*...
gi 8922328    307 aaRGKEKEKDGTTDSGIK 324
Cdd:TIGR01628  79 --RDPSLRRSGVGNIFVK 94

RNA recognition motif 2 (RRM2) found in Deleted in azoospermia-associated protein 1 (DAZAP1) and similar proteins; This subfamily corresponds to the RRM2 of DAZAP1 or DAZ-associated protein 1, also termed proline-rich RNA binding protein (Prrp), a multi-functional ubiquitous RNA-binding protein expressed most abundantly in the testis and essential for normal cell growth, development, and spermatogenesis. DAZAP1 is a shuttling protein whose acetylated is predominantly nuclear and the nonacetylated form is in cytoplasm. DAZAP1 also functions as a translational regulator that activates translation in an mRNA-specific manner. DAZAP1 was initially identified as a binding partner of Deleted in Azoospermia (DAZ). It also interacts with numerous hnRNPs, including hnRNP U, hnRNP U like-1, hnRNPA1, hnRNPA/B, and hnRNP D, suggesting DAZAP1 might associate and cooperate with hnRNP particles to regulate adenylate-uridylate-rich elements (AU-rich element or ARE)-containing mRNAs. DAZAP1 contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal proline-rich domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 8922328  234 LYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQ------CAFIQFATRQAAEVAAEKSFNKLivNGRRLNVK 301
Cdd:cd12327   5 VFVGGIPHNCGETELRDYFKRYGVVTEVVMMYDAEkqrsrgFGFITFEDEQSVDQAVNMHFHDI--MGKKVEVK 76

RNA recognition motif 3 (RRM3) found in putative RNA-binding protein 15B (RBM15B) from vertebrate; This subgroup corresponds to the RRM3 of RBM15B, also termed one twenty-two 3 (OTT3), a paralog of RNA binding motif protein 15 (RBM15), also known as One-twenty two protein 1 (OTT1). Like RBM15, RBM15B has post-transcriptional regulatory activity. It is a nuclear protein sharing with RBM15 the association with the splicing factor compartment and the nuclear envelope as well as the binding to mRNA export factors NXF1 and Aly/REF. RBM15B belongs to the Spen (split end) protein family, which shares a domain architecture comprising of three N-terminal RNA recognition motifs (RRMs), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal SPOC (Spen paralog and ortholog C-terminal) domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 8922328  232 TTLYVGGLGDTITETDLRNHFYQFGEIRTITVVQRQQCAFIQFATRQAAEVAAEK 286
Cdd:cd12558   3 TRLWVGGLGPNTSLAALAREFDRFGSIRTIDYVKGDSFAYIQYESLDAAQAACAQ 57

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.