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
                 ....*....|....*....|....*....|....*....|....*..
gi 767962178 386 YAFLLFQEESSVQALIDACLEEDGKLYLCVSSPTIKDKPVQIRPWNL 432
Cdd:cd12724   46 YAFLLFQDERSVQALIDACIEEDDKLYLCVSSPTIKDKPVQIRPWNL 92

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
                 ....*....|....*....|....*....|....*....|....*..
gi 767962178 386 YAFLLFQEESSVQALIDACLEEDGKLYLCVSSPTIKDKPVQIRPWNL 432
Cdd:cd12724   46 YAFLLFQDERSVQALIDACIEEDDKLYLCVSSPTIKDKPVQIRPWNL 92

RNA recognition motif;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 767962178  386 YAFLLFQEESSVQALIDACLEEDGKLYLCVSSPTIKDKPVQIRP 429
Cdd:pfam16367  48 YVFLVFEDEKSVQALLDACTQEDGKYYLKLSSPRMKDKPVQIRP 91

B-box-type 1 zinc finger (Bbox1); The B-box-type zinc finger is a short zinc binding domain of around 40 amino acid residues in length. It has been found in transcription factors, ribonucleoproteins and proto-oncoproteins, such as in TRIM (tripartite motif) proteins that consist of an N-terminal RING finger (originally called an A-box), followed by 1-2 B-box domains and a coiled-coil domain (also called RBCC for Ring, B-box, Coiled-Coil). The B-box-type zinc finger often presents in combination with other motifs, like RING zinc finger, NHL motif, coiled-coil or RFP domain, in functionally unrelated proteins, most likely mediating protein-protein interactions. Based on different consensus sequences and the spacing of the 7-8 zinc-binding residues, the B-box-type zinc fingers can be divided into two groups, type 1 (Bbox1: C6H2) and type 2 (Bbox2: CHC3H2). This family corresponds to the type 1 B-box (Bbox1).

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 767962178 535 MCDECQGTRcggkfAPFFCanVTCLQYYCEYCWASIHSR 573
Cdd:cd19757    1 LCDECEERE-----ATVYC--LECEEFLCDDCSDAIHRR 32

RNA recognition motif 2 (RRM2) found in cytoplasmic polyadenylation element-binding protein CPEB-1, CPEB-2, CPEB-3, CPEB-4 and similar protiens; This subfamily corresponds to the RRM2 of CPEB family of proteins that bind to defined groups of mRNAs and act as either translational repressors or activators to regulate their translation. CPEB proteins are well conserved in both, vertebrates and invertebrates. Based on sequence similarity, RNA-binding specificity, and functional regulation of translation, the CPEB proteins has been classified into two subfamilies. The first subfamily includes CPEB-1 and related proteins. CPEB-1 is an RNA-binding protein that interacts with the cytoplasmic polyadenylation element (CPE), a short U-rich motif in the 3' untranslated regions (UTRs) of certain mRNAs. It functions as a translational regulator that plays a major role in the control of maternal CPE-containing mRNA in oocytes, as well as of subsynaptic CPE-containing mRNA in neurons. Once phosphorylated and recruiting the polyadenylation complex, CPEB-1 may function as a translational activator stimulating polyadenylation and translation. Otherwise, it may function as a translational inhibitor when dephosphorylated and bound to a protein such as maskin or neuroguidin, which blocks translation initiation through interfering with the assembly of eIF-4E and eIF-4G. Although CPEB-1 is mainly located in cytoplasm, it can shuttle between nucleus and cytoplasm. The second subfamily includes CPEB-2, CPEB-3, CPEB-4, and related protiens. Due to the high sequence similarity, members in this subfamily 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 CPEB proteins are nucleus-cytoplasm shuttling proteins. They contain an N-terminal unstructured region, followed by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a Zn-finger motif. CPEB-2, -3, and -4 have conserved nuclear export signals that are not present in CPEB-1.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767962178 449 KTIFVGGVPRPLRAVELAMIMDRLYGGVCYAGIDTDPELKYPKGAGRVAFSNQQSYIAAISARFVQLQHNDIDKRVEVKP 528
Cdd:cd12445    1 RTVFVGGLPLPLTAAELAAILERLYGGVCYVEIDTDEFYLYPTGCARVTFNNEQSYIKAVSEVFVELPFGTINKRVRIRP 80

                 .
gi 767962178 529 Y 529
Cdd:cd12445   81 Y 81

RNA recognition motif 2 (RRM2) found in cytoplasmic polyadenylation element-binding protein 1 (CPEB-1) and similar proteins; This subgroup corresponds to the RRM2 of CPEB-1 (also termed CPE-BP1 or CEBP), an RNA-binding protein that interacts with the cytoplasmic polyadenylation element (CPE), a short U-rich motif in the 3' untranslated regions (UTRs) of certain mRNAs. It functions as a translational regulator that plays a major role in the control of maternal CPE-containing mRNA in oocytes, as well as of subsynaptic CPE-containing mRNA in neurons. Once phosphorylated and recruiting the polyadenylation complex, CPEB-1 may function as a translational activator stimulating polyadenylation and translation. Otherwise, it may function as a translational inhibitor when dephosphorylated and bound to a protein such as maskin or neuroguidin, which blocks translation initiation through interfering with the assembly of eIF-4E and eIF-4G. Although CPEB-1 is mainly located in cytoplasm, it can shuttle between nucleus and cytoplasm. CPEB-1 contains 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. Both of the RRMs and the Zn finger are required for CPEB-1 to bind CPE. The N-terminal regulatory region may be responsible for CPEB-1 interacting with other proteins.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767962178 446 DPRKTIFVGGVPRPLRAVELAMIMDRLYGGVCYAGIDTDpELKYPKGAGRVAFSNQQSYIAAISARFVQLQHNDIDKRVE 525
Cdd:cd12725    1 DPSKTVFVGALHGMLNAEGLANIMNDLFGGVVYAGIDTD-KHKYPIGSGRVTFNNQRSYMKAVNAAFVEIKTPKFTKKVQ 79

                 ....
gi 767962178 526 VKPY 529
Cdd:cd12725   80 IDPY 83

RNA recognition motif 1 (RRM1) found in cytoplasmic polyadenylation element-binding protein CPEB-1, CPEB-2, CPEB-3, CPEB-4 and similar protiens; This subfamily corresponds to the RRM1 of the CPEB family of proteins that bind to defined groups of mRNAs and act as either translational repressors or activators to regulate their translation. CPEB proteins are well conserved in both, vertebrates and invertebrates. Based on sequence similarity, RNA-binding specificity, and functional regulation of translation, the CPEB proteins have been classified into two subfamilies. The first subfamily includes CPEB-1 and related proteins. CPEB-1 is an RNA-binding protein that interacts with the cytoplasmic polyadenylation element (CPE), a short U-rich motif in the 3' untranslated regions (UTRs) of certain mRNAs. It functions as a translational regulator that plays a major role in the control of maternal CPE-containing mRNA in oocytes, as well as of subsynaptic CPE-containing mRNA in neurons. Once phosphorylated and recruiting the polyadenylation complex, CPEB-1 may function as a translational activator stimulating polyadenylation and translation. Otherwise, it may function as a translational inhibitor when dephosphorylated and bind to a protein such as maskin or neuroguidin, which blocks translation initiation through interfering with the assembly of eIF-4E and eIF-4G. Although CPEB-1 is mainly located in cytoplasm, it can shuttle between nucleus and cytoplasm. The second subfamily includes CPEB-2, CPEB-3, CPEB-4, and related protiens. Due to high sequence similarity, members in this subfamily 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. 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 CPEB proteins are nucleus-cytoplasm shuttling proteins. They contain an N-terminal unstructured region, followed by two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a Zn-finger motif. CPEB-2, -3, and -4 have conserved nuclear export signals that are not present in CPEB-1.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 767962178 386 YAFLLFQEESSVQALIDACLEEDGKL---YLCVSSPTIKDKPVQIRPWNL 432
Cdd:cd12444   46 YVYLLFESEKSVQALLQACTHDDDKLyeyYFKVSSRTMKDKEVQVIPWVL 95

RNA recognition motif 1 (RRM1) found in cytoplasmic polyadenylation element-binding protein 1 (CPEB-1) and similar proteins; This subgroup corresponds to the RRM2 of CPEB-1 (also termed CPE-BP1 or CEBP), an RNA-binding protein that interacts with the cytoplasmic polyadenylation element (CPE), a short U-rich motif in the 3' untranslated regions (UTRs) of certain mRNAs. It functions as a translational regulator that plays a major role in the control of maternal CPE-containing mRNA in oocytes, as well as of subsynaptic CPE-containing mRNA in neurons. Once phosphorylated and recruiting the polyadenylation complex, CPEB-1 may function as a translational activator stimulating polyadenylation and translation. Otherwise, it may function as a translational inhibitor when dephosphorylated and bound to a protein such as maskin or neuroguidin, which blocks translation initiation through interfering with the assembly of eIF-4E and eIF-4G. Although CPEB-1 is mainly located in cytoplasm, it can shuttle between nucleus and cytoplasm. CPEB-1 contains 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. Both of the RRMs and the Zn finger are required for CPEB-1 to bind CPE. The N-terminal regulatory region may be responsible for CPEB-1 interacting with other proteins.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 767962178 386 YAFLLFQEESSVQALIDAC---LEEDGKLYLCVSSPTIKDKPVQIRPWNLSDS 435
Cdd:cd12723   49 YVYLIFESEKSVKALLQACthdFLGGGEYYFKISSRRMRSKEVQVIPWVLSDS 101

RNA recognition motif;

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 767962178   450 TIFVGGVPRPLRAVELAMIMDRlYGGVCYAGIDTDPELKYPKGAGRVAFSNQQSYIAAISA 510
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSK-FGKVESVRLVRDKETGKSKGFAFVEFESEEDAEKALEA 60

RNA recognition motif 2 (RRM2) found in yeast protein gar2 and similar proteins; This subfamily corresponds to the RRM2 of yeast protein gar2, a novel nucleolar protein required for 18S rRNA and 40S ribosomal subunit accumulation. It shares similar domain architecture with nucleolin from vertebrates and NSR1 from Saccharomyces cerevisiae. The highly phosphorylated N-terminal domain of gar2 is made up of highly acidic regions separated from each other by basic sequences, and contains multiple phosphorylation sites. The central domain of gar2 contains two closely adjacent N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The C-terminal RGG (or GAR) domain of gar2 is rich in glycine, arginine and phenylalanine residues.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 767962178 473 YGGVCYAGIDTDPELKYPKGAGRVAFSNQQSYIAAISArfvqLQHNDIDKR 523
Cdd:cd12448   22 HGSIVSVRLPTDRETGQPKGFGYVDFSTIDSAEAAIDA----LGGEYIDGR 68