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 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12223   1 TTNLYVGNLPPSVTEEVLLREFGRFGPLASVKIMWPRTEEERRRNRNCGFVAFMSRADAERAMRELNGKDVMGYELKLGW 80

                ....
gi 19922658 294 GKTV 297
Cdd:cd12223  81 GKAV 84

cwf21 domain found in U2-associated protein SR140 and similar proteins; SR140, also called U2 snRNP-associated SURP motif-containing protein, U2SURP, or 140 kDa Ser/Arg-rich domain protein, is a putative splicing factor mainly found in higher eukaryotes. Although it was initially identified as a 17S U2 snRNP-associated protein, the molecular and physiological function of SR140 remains unclear. This model represents the cwf21 domain of SR140 and similar proteins. The cwf21 domain is involved in mRNA splicing; it binds directly to the spliceosomal protein Prp8.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 19922658 778 YTDEMRQKLRDIESKAIQYQDELESGKRRLEPGWSVPEQVEQFRKRLLKQ 827
Cdd:cd21370   1 IDEERRAKLREIELKVMKYQDELESGKRSRKPGESISEQVEQYRKKLLKK 50

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 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12223   1 TTNLYVGNLPPSVTEEVLLREFGRFGPLASVKIMWPRTEEERRRNRNCGFVAFMSRADAERAMRELNGKDVMGYELKLGW 80

                ....
gi 19922658 294 GKTV 297
Cdd:cd12223  81 GKAV 84

cwf21 domain found in U2-associated protein SR140 and similar proteins; SR140, also called U2 snRNP-associated SURP motif-containing protein, U2SURP, or 140 kDa Ser/Arg-rich domain protein, is a putative splicing factor mainly found in higher eukaryotes. Although it was initially identified as a 17S U2 snRNP-associated protein, the molecular and physiological function of SR140 remains unclear. This model represents the cwf21 domain of SR140 and similar proteins. The cwf21 domain is involved in mRNA splicing; it binds directly to the spliceosomal protein Prp8.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 19922658 778 YTDEMRQKLRDIESKAIQYQDELESGKRRLEPGWSVPEQVEQFRKRLLKQ 827
Cdd:cd21370   1 IDEERRAKLREIELKVMKYQDELESGKRSRKPGESISEQVEQYRKKLLKK 50

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 19922658    216 NLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRseeEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:smart00360   1 TLFVGNLPPDTTEEELRELFSKFGKVESVRLVRDK---ETGKSKGFAFVEFESEEDAEKALEALNGKELDGRPLKV 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 19922658   217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprsEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMR 290
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLV----RDETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:COG0724   1 SMKIYVGNLPYSVTEEDLRELFSEYGEVTSVKLI---TDRETGRSRGFGFVEMPDDEEAQAAIEALNGAELMG 70

CID (CTD-Interacting Domain) of Regulation of nuclear pre-mRNA domain-containing proteins; This family is composed of Regulation of nuclear pre-mRNA domain-containing proteins 1A (RPRD1A), 1B (RPRD1B), 2 (RPRD2), yeast Rtt103, and similar proteins. RPRD1A, RPRD1B, and RPRD2 are CID (CTD-Interacting Domain) containing proteins that co-purify with RNA polymerase (Pol) II (RNAP II) and three other RNAP II-associated proteins, RPAP2, GRINL1A and RECQL5, but not with the Mediator complex. Yeast transcription termination factor Rtt103 is a CID containing protein that functions in DNA damage response. CID binds tightly to the carboxy-terminal domain (CTD) of RNAP II. During transcription, RNAP II synthesizes eukaryotic messenger RNA. Transcription is coupled to RNA processing through the CTD, which consists of up to 52 repeats of the sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. CID contains eight alpha-helices in a right-handed superhelical arrangement, which closely resembles that of the VHS domains and ARM (Armadillo) repeat proteins, except for its two amino-terminal helices.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 19922658 482 RNRLEDLIRHLTPERARIGDAMIFCIEHADAADEICECIAESLSNINTlaSKKIARLYLISDILHNCTVKvaNASFFRKS 561
Cdd:cd16981   1 EEALEKKLRSLNNTQQSIQTLSLWCLFHKKHAKQIVKIWLKELKKAKP--ERKLTLLYLANDVLQNSRRK--GAPEFVEA 76

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|...
gi 19922658 562 VEKQLLDIFDNLhnyylnieSRLKAEGFKSRVCNVIRTWEEWTIYPKDFMAQL 614
Cdd:cd16981  77 FKKVLPEALALV--------RSEGDESVRKKVLRVLNIWEERNVFGSEFLAEL 121

glycine-rich RNA-binding protein 4; Provisional

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 19922658  214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRseeEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:PLN03134  34 STKLFIGGLSWGTDDASLRDAFAHFGDVVDAKVIVDR---ETGRSRGFGFVNFNDEGAATAAISEMDGKELNGRHIRV 108

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 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12223   1 TTNLYVGNLPPSVTEEVLLREFGRFGPLASVKIMWPRTEEERRRNRNCGFVAFMSRADAERAMRELNGKDVMGYELKLGW 80

                ....
gi 19922658 294 GKTV 297
Cdd:cd12223  81 GKAV 84

cwf21 domain found in U2-associated protein SR140 and similar proteins; SR140, also called U2 snRNP-associated SURP motif-containing protein, U2SURP, or 140 kDa Ser/Arg-rich domain protein, is a putative splicing factor mainly found in higher eukaryotes. Although it was initially identified as a 17S U2 snRNP-associated protein, the molecular and physiological function of SR140 remains unclear. This model represents the cwf21 domain of SR140 and similar proteins. The cwf21 domain is involved in mRNA splicing; it binds directly to the spliceosomal protein Prp8.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 19922658 778 YTDEMRQKLRDIESKAIQYQDELESGKRRLEPGWSVPEQVEQFRKRLLKQ 827
Cdd:cd21370   1 IDEERRAKLREIELKVMKYQDELESGKRSRKPGESISEQVEQYRKKLLKK 50

Surp module; This domain is also known as the SWAP domain. SWAP stands for Suppressor-of-White-APricot. It has been suggested that these domains may be RNA binding.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 19922658   373 NVIHRMIEFVIREGPMFEALIMIREMENPLFAFLFDNESPAHIYYRWKLFS 423
Cdd:pfam01805   1 DIIKKTAQFVARNGPEFEALLMEREERNPQFDFLFDPDDPLHAYYRWKLEE 51

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 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRseeeKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd00590   1 LFVGNLPPDTTEEDLRELFSKFGEVVSVRIVRDR----DGKSKGFAFVEFESPEDAEKALEALNGTELGGRPLKV 71

RNA recognition motif 1 (RRM1) found in granule-associated RNA binding proteins p40-TIA-1 and TIAR; This subfamily corresponds to the RRM1 of nucleolysin TIA-1 isoform p40 (p40-TIA-1 or TIA-1) and nucleolysin TIA-1-related protein (TIAR), both of which are granule-associated RNA binding proteins involved in inducing apoptosis in cytotoxic lymphocyte (CTL) target cells. TIA-1 and TIAR share high sequence similarity. They 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.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprseEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12352   1 LYVGNLDRQVTEDLILQLFSQIGPCKSCKMI-----TEHGGNDPYCFVEFYEHNHAAAALQAMNGRKILGKEVKVNW 72

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 19922658   217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprsEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMR 290
Cdd:pfam00076   1 LFVGNLPPDTTEEDLKDLFSKFGPIKSIRLV----RDETGRSKGFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in eukaryotic RNA-binding protein 18 and similar proteins; This subfamily corresponds to the RRM of RBM18, a putative RNA-binding protein containing a well-conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). The biological role of RBM18 remains unclear.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 19922658 216 NLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:cd12355   1 RLWIGNLDPRLTEYHLLKLLSKYGKIKKFDFLFHKTGPLKGQPRGYCFVTFETKEEAEKAIECLNGKLALG 71

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwpRSEEEKQRGrnCGFVAYMSRKDAERALKTLNGRYIMGYEMRLG 292
Cdd:cd12380   2 TNVYVKNFGEDVDDDELKELFEKYGKITSAKVM--KDDSGKSKG--FGFVNFENHEAAQKAVEELNGKELNGKKLYVG 75

RNA recognition motif 1 (RRM1) found in type I polyadenylate-binding proteins; This subfamily corresponds to the RRM1 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 a 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 mammals, 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 yeast PABP, a conserved poly(A) binding protein containing poly(A) tails that can be attached to the 3'-ends of mRNAs. The yeast PABP and its homologs may play important roles in the initiation of translation and in mRNA decay. Like vertebrate PABP-1, the yeast PABP contains four RRMs, a linker region, and a proline-rich CTD as well. The first two RRMs are mainly responsible for specific binding to poly(A). The proline-rich region may be involved in protein-protein interactions.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKI---MWPRseeekqRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12378   2 LYVGDLHPDVTEAMLYEKFSPAGPVLSIRVcrdAVTR------RSLGYAYVNFQQPADAERALDTLNFDVIKGKPIRIMW 75

RNA recognition motif (RRM) found in the Aly/REF family; This subfamily corresponds to the RRM of Aly/REF family which includes THO complex subunit 4 (THOC4, also termed Aly/REF), S6K1 Aly/REF-like target (SKAR, also termed PDIP3 or PDIP46) and similar proteins. THOC4 is an mRNA transporter protein with a well conserved RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). It is involved in RNA transportation from the nucleus, and was initially identified as a transcription coactivator of LEF-1 and AML-1 for the TCRalpha enhancer function. In addition, THOC4 specifically binds to rhesus (RH) promoter in erythroid, and might be a novel transcription cofactor for erythroid-specific genes. SKAR shows high sequence homology with THOC4 and possesses one RRM as well. SKAR is widely expressed and localizes to the nucleus. It may be a critical player in the function of S6K1 in cell and organism growth control by binding the activated, hyperphosphorylated form of S6K1 but not S6K2. Furthermore, SKAR functions as a protein partner of the p50 subunit of DNA polymerase delta. In addition, SKAR may have particular importance in pancreatic beta cell size determination and insulin secretion.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSeeekqrGRN--CGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd12418   1 TRVRVSNLHPDVTEEDLRELFGRVGPVKSVKINYDRS------GRStgTAYVVFERPEDAEKAIKQFDGVLLDGQPMKV 73

RNA recognition motif 2 (RRM2) found in yeast nuclear and cytoplasmic polyadenylated RNA-binding protein PUB1 and similar proteins; This subgroup corresponds to the RRM2 of yeast protein PUB1, also termed ARS consensus-binding protein ACBP-60, or poly uridylate-binding protein, or poly(U)-binding protein. PUB1 has been identified as both, a heterogeneous nuclear RNA-binding protein (hnRNP) and a cytoplasmic mRNA-binding protein (mRNP), which may be stably bound to a translationally inactive subpopulation of mRNAs within the cytoplasm. It 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 RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a GAR motif (glycine and arginine rich stretch) that is located between RRM2 and RRM3.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 19922658 216 NLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWprsEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12619   3 NIFVGDLSPEVTDAALFNAFSDFPSCSDARVMW---DQKTGRSRGYGFVSFRSQQDAQNAINSMNGKWLGSRPIRCNW 77

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 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLG 292
Cdd:cd12284   1 LYVGSLHFNITEDMLRGIFEPFGKIEFVQLQ---KDPETGRSKGYGFIQFRDAEDAKKALEQLNGFELAGRPMKVG 73

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRseeEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd12399   1 LYVGNLPYSASEEQLKSLFGQFGAVFDVKLPMDR---ETKRPRGFGFVELQEEESAEKAIAKLDGTDFMGRTIRV 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 19922658   217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:TIGR01628   3 LYVGDLDPDVTEAKLYDLFKPFGPVLSVRVC---RDSVTRRSLGYGYVNFQNPADAERALETMNFKRLGGKPIRIMW 76

RNA recognition motif (RRM) found in SR-related and CTD-associated factor 4 (SCAF4), SR-related and CTD-associated factor 8 (SCAF8) and similar proteins; This subfamily corresponds to the RRM in a new class of SCAFs (SR-like CTD-associated factors), including SCAF4, SCAF8 and similar proteins. The biological role of SCAF4 remains unclear, but it shows high sequence similarity to SCAF8 (also termed CDC5L complex-associated protein 7, or RNA-binding motif protein 16, or CTD-binding SR-like protein RA8). SCAF8 is 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. In addition, 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 and SCAF4 both contain a conserved N-terminal CTD-interacting domain (CID), an atypical RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNPs (ribonucleoprotein domain), and serine/arginine-rich motifs.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSeeekqrgrnCGFVAYMSRKDAERALKTLNGRYIMGYEMRLGW 293
Cdd:cd12227   2 STTLWVGHLSKKVTQEELKNLFEEYGEIQSIDMIPPRG---------CAYVCMKTRQDAHRALQKLKNHKLRGKSIKIAW 72

RNA recognition motif 2 (RRM2) found in RNA-binding protein 28 (RBM28) and similar proteins; This subfamily corresponds to the RRM2 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 19922658 221 NLNPKISEQQLMEIFGRYGPLASIKImwPRSEEEKQRGrnCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:cd12414   6 NLPFKCTEDDLKKLFSKFGKVLEVTI--PKKPDGKLRG--FAFVQFTNVADAAKAIKGMNGKKIKG 67

RNA recognition motif 2 (RRM2) found in Nicotiana sylvestris chloroplastic 33 kDa ribonucleoprotein (NsCP33) and similar proteins; The family includes NsCP33, Arabidopsis thaliana chloroplastic 31 kDa ribonucleoprotein (CP31A) and mitochondrial glycine-rich RNA-binding protein 2 (AtGR-RBP2). NsCP33 may be involved in splicing and/or processing of chloroplast RNA's. AtCP31A, also called RNA-binding protein 1/2/3 (AtRBP33), or RNA-binding protein CP31A, or RNA-binding protein RNP-T, or RNA-binding protein cp31, is required for specific RNA editing events in chloroplasts and stabilizes specific chloroplast mRNAs, as well as for normal chloroplast development under cold stress conditions by stabilizing transcripts of numerous mRNAs under these conditions. CP31A may modulate telomere replication through RNA binding domains. AtGR-RBP2, also called AtRBG2, or glycine-rich protein 2 (AtGRP2), or mitochondrial RNA-binding protein 1a (At-mRBP1a), plays a role in RNA transcription or processing during stress. It binds RNAs and DNAs sequence with a preference to single-stranded nucleic acids. AtGR-RBP2 displays strong affinity to poly(U) sequence. It exerts cold and freezing tolerance, probably by exhibiting an RNA chaperone activity during the cold and freezing adaptation process. Some members in this family contain two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The model corresponds to the second RRM motif.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 19922658 216 NLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRseeEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:cd21608   1 KLYVGNLSWDTTEDDLRDLFSEFGEVESAKVITDR---ETGRSRGFGFVTFSTAEAAEAAIDALNGKELDG 68

RNA recognition motif (RRM) found in heterogeneous nuclear ribonucleoprotein G (hnRNP G), Y chromosome RNA recognition motif 1 (hRBMY), testis-specific heterogeneous nuclear ribonucleoprotein G-T (hnRNP G-T) and similar proteins; This subfamily corresponds to the RRM domain of hnRNP G, also termed glycoprotein p43 or RBMX, an RNA-binding motif protein located on the X chromosome. It is expressed ubiquitously and has been implicated in the splicing control of several pre-mRNAs. Moreover, hnRNP G may function as a regulator of transcription for SREBP-1c and GnRH1. Research has shown that hnRNP G may also act as a tumor-suppressor since it upregulates the Txnip gene and promotes the fidelity of DNA end-joining activity. In addition, hnRNP G appears to play a critical role in proper neural development of zebrafish and frog embryos. The family also includes several paralogs of hnRNP G, such as hRBMY and hnRNP G-T (also termed RNA-binding motif protein, X-linked-like-2). Both, hRBMY and hnRNP G-T, are exclusively expressed in testis and critical for male fertility. Like hnRNP G, hRBMY and hnRNP G-T interact with factors implicated in the regulation of pre-mRNA splicing, such as hTra2-beta1 and T-STAR. Although members in this family share a high conserved N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), they appear to recognize different RNA targets. For instance, hRBMY interacts specifically with a stem-loop structure in which the loop is formed by the sequence CA/UCAA. In contrast, hnRNP G associates with single stranded RNA sequences containing a CCA/C motif. In addition to the RRM, hnRNP G contains a nascent transcripts targeting domain (NTD) in the middle region and a novel auxiliary RNA-binding domain (RBD) in its C-terminal region. The C-terminal RBD exhibits distinct RNA binding specificity, and would play a critical role in the regulation of alternative splicing by hnRNP G.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:cd12382   2 GKLFIGGLNTETNEKALEAVFGKYGRIVEVLLM---KDRETNKSRGFAFVTFESPADAKDAARDMNGKELDG 70

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 19922658   209 TGDPNTTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprsEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYI 284
Cdd:TIGR01628 173 APLKKFTNLYVKNLDPSVNEDKLRELFAKFGEITSAAVM----KDGSGRSRGFAFVNFEKHEDAAKAVEEMNGKKI 244

RNA recognition motif 1 (RRM1) found in nucleolysin TIAR and similar proteins; This subgroup corresponds to the RRM1 of nucleolysin TIAR, also termed TIA-1-related protein, and 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        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprsEEEKQRGRNCgFVAYMSRKDAERALKTLNGRYIMGYEMRLGWGKT 296
Cdd:cd12616   2 LYVGNLSRDVTEVLILQLFSQIGPCKSCKMI----TEHTSNDPYC-FVEFYEHRDAAAALAAMNGRKILGKEVKVNWATT 76

RNA recognition motif 2 (RRM2) found in the Hu proteins family, Drosophila sex-lethal (SXL), and similar proteins; This subfamily corresponds to the RRM2 of Hu proteins and SXL. The Hu proteins family represents a group of RNA-binding proteins involved in diverse biological processes. Since the Hu proteins share high homology with the Drosophila embryonic lethal abnormal vision (ELAV) protein, the Hu family is sometimes referred to as the ELAV family. Drosophila ELAV is exclusively expressed in neurons and is required for the correct differentiation and survival of neurons in flies. The neuronal members of the Hu family include Hu-antigen B (HuB or ELAV-2 or Hel-N1), Hu-antigen C (HuC or ELAV-3 or PLE21), and Hu-antigen D (HuD or ELAV-4), which play important roles in neuronal differentiation, plasticity and memory. HuB is also expressed in gonads. Hu-antigen R (HuR or ELAV-1 or HuA) is 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. Also included in this subfamily is the sex-lethal protein (SXL) from Drosophila melanogaster. SXL governs sexual differentiation and X chromosome dosage compensation in flies. It induces female-specific alternative splicing of the transformer (tra) pre-mRNA by binding to the tra uridine-rich polypyrimidine tract at the non-sex-specific 3' splice site during the sex-determination process. SXL binds also to its own pre-mRNA and promotes female-specific alternative splicing. SXL contains an N-terminal Gly/Asn-rich domain that may be responsible for the protein-protein interaction, and tandem RRMs that show high preference to bind single-stranded, uridine-rich target RNA transcripts.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMG 286
Cdd:cd12376   1 ANLYVSGLPKTMTQKELEQLFSQYGRIITSRIL---RDQLTGVSRGVGFIRFDKRIEAEEAIKGLNGQKPEG 69

RNA recognition motif 1 (RRM1) found in yeast nucleolar protein 3 (Npl3p) and similar proteins; This subfamily corresponds to the RRM1 of Npl3p, also termed mitochondrial targeting suppressor 1 protein, or nuclear polyadenylated RNA-binding protein 1. Npl3p is a major yeast RNA-binding protein that competes with 3'-end processing factors, such as Rna15, for binding to the nascent RNA, protecting the transcript from premature termination and coordinating transcription termination and the packaging of the fully processed transcript for export. It specifically recognizes a class of G/U-rich RNAs. Npl3p is a multi-domain protein containing two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), separated by a short linker and a C-terminal domain rich in glycine, arginine and serine residues.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprseeekqRGRNCGFVAYMSRKDAERALKTLNGRY 283
Cdd:cd12340   2 LFVRPFPPDTSESAIREIFSPYGPVKEVKML---------SDSNFAFVEFEELEDAIRAKDSVHGRV 59

RNA recognition motif 1 (RRM1) 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 first RRM motif.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWpRSEEEKQRGRncGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd21601   1 TALFIGDLDKDVTEEMLRDIFSKYKSLVSVKICL-DSETKKSLGY--GYLNFSDKEDAEKAIEEFNYTPIFGKEVRI 74

RNA recognition motif (RRM) found in nuclear cap-binding protein subunit 2 (CBP20) and similar proteins; This subfamily corresponds to the RRM of CBP20, also termed nuclear cap-binding protein subunit 2 (NCBP2), or cell proliferation-inducing gene 55 protein, or NCBP-interacting protein 1 (NIP1). CBP20 is the small subunit of the nuclear cap binding complex (CBC), which is a conserved eukaryotic heterodimeric protein complex binding to 5'-capped polymerase II transcripts and plays a central role in the maturation of pre-mRNA and uracil-rich small nuclear RNA (U snRNA). CBP20 is most likely responsible for the binding of capped RNA. It contains an RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and interacts with the second and third domains of CBP80, the large subunit of CBC.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIkIMwprseeekqrGRN------CG--FVAYMSRKDAERALKTLNGRYIMGYE 288
Cdd:cd12240   1 LYVGNLSFYTTEEQIYELFSKCGDIKRI-IM----------GLDkfkktpCGfcFVEYYSREDAENAVKYLNGTKLDDRI 69

                ....*
gi 19922658 289 MRLGW 293
Cdd:cd12240  70 IRVDW 74

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        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 19922658 217 LYLGNLNPKISEQQLMEIFGRYGPLASIKImwPrSEEEKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd12448   1 LFVGNLPFSATQDALYEAFSQHGSIVSVRL--P-TDRETGQPKGFGYVDFSTIDSAEAAIDALGGEYIDGRPIRL 72

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 19922658 214 TTNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMwprseeekqRGRNCGFVAYMSRKDAERALKTL 279
Cdd:cd12523   3 SRNVYLGNLPESITEEELREDLEKFGPIDQIKIV---------KEKNIAFVHFLSIANAIKVVTTL 59

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

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 19922658 221 NLNPKISEQQLMEIFGRYGPLASIKIMwpRSEEEKQRGrnCGFVAYMSRKDAERALKTLNGRYI 284
Cdd:cd12564   7 NLPSSITEDRLRKLFSAFGTITDVQLK--YTKDGKFRR--FGFVGFKSEEEAQKALKHFNNSFI 66

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 19922658 215 TNLYLGNLNPKISEQQLMEIFGRYGPLASIKIMWPRSeeeKQRGRNCGFVAYMSRKDAERALKTLNGRYIMGYEMRL 291
Cdd:cd12651   3 TNLYVTNLPRTITEDELDTIFGAYGNIVQKNLLRDKL---TGRPRGVAFVRYDKREEAQAAISALNGTIPEGGTQPL 76

RNA recognition motif (RRM) found in serine/arginine-rich splicing factor 3 (SRSF3) and similar proteins; This subfamily corresponds to the RRM of two serine/arginine (SR) proteins, serine/arginine-rich splicing factor 3 (SRSF3) and serine/arginine-rich splicing factor 7 (SRSF7). SRSF3, also termed pre-mRNA-splicing factor SRp20, modulates alternative splicing by interacting with RNA cis-elements in a concentration- and cell differentiation-dependent manner. It is also involved in termination of transcription, alternative RNA polyadenylation, RNA export, and protein translation. SRSF3 is critical for cell proliferation, and tumor induction and maintenance. It can shuttle between the nucleus and cytoplasm. SRSF7, also termed splicing factor 9G8, plays a crucial role in both constitutive splicing and alternative splicing of many pre-mRNAs. Its localization and functions are tightly regulated by phosphorylation. SRSF7 is predominantly present in the nuclear and can shuttle between nucleus and cytoplasm. It cooperates with the export protein, Tap/NXF1, helps mRNA export to the cytoplasm, and enhances the expression of unspliced mRNA. Moreover, SRSF7 inhibits tau E10 inclusion through directly interacting with the proximal downstream intron of E10, a clustering region for frontotemporal dementia with Parkinsonism (FTDP) mutations. Both SRSF3 and SRSF7 contain a single N-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal RS domain rich in serine-arginine dipeptides. The RRM domain is involved in RNA binding, and the RS domain has been implicated in protein shuttling and protein-protein interactions.