RNA recognition motif (RRM) found in UHM domain of 45 kDa-splicing factor (SPF45) and similar proteins; This subgroup corresponds to the RRM of SPF45, also termed RNA-binding motif protein 17 (RBM17), an RNA-binding protein consisting of an unstructured N-terminal region, followed by a G-patch motif and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors a RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain) and an Arg-Xaa-Phe sequence motif. SPF45 regulates alternative splicing of the apoptosis regulatory gene FAS (also known as CD95). It induces exon 6 skipping in FAS pre-mRNA through the UHM domain that binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) present in the 3' splice site-recognizing factors U2AF65, SF1 and SF3b155.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 300 PSKVVLLRNMVGPGEVDEDLEPEVKDECnTKYGEVVRVVIFEQPNVPSDEAVRIFVEFRRIESAIKAVVDLNGRFFGGRQ 379
Cdd:cd12647     1 PSKVVLLRNMVGPGEVDEDLEPEVKEEC-EKYGKVTKVVIFEIPGAPDDEAVRIFVEFERVESAIKAVVDLNGRFFGGRT 79

                          90
                  ....*....|....*.
gi 1227964562 380 VKAGFYSWEKLNNLEL 395
Cdd:cd12647    80 VKASFYDLDRFRRLDL 95

RNA recognition motif (RRM) found in UHM domain of 45 kDa-splicing factor (SPF45) and similar proteins; This subgroup corresponds to the RRM of SPF45, also termed RNA-binding motif protein 17 (RBM17), an RNA-binding protein consisting of an unstructured N-terminal region, followed by a G-patch motif and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors a RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain) and an Arg-Xaa-Phe sequence motif. SPF45 regulates alternative splicing of the apoptosis regulatory gene FAS (also known as CD95). It induces exon 6 skipping in FAS pre-mRNA through the UHM domain that binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) present in the 3' splice site-recognizing factors U2AF65, SF1 and SF3b155.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 300 PSKVVLLRNMVGPGEVDEDLEPEVKDECnTKYGEVVRVVIFEQPNVPSDEAVRIFVEFRRIESAIKAVVDLNGRFFGGRQ 379
Cdd:cd12647     1 PSKVVLLRNMVGPGEVDEDLEPEVKEEC-EKYGKVTKVVIFEIPGAPDDEAVRIFVEFERVESAIKAVVDLNGRFFGGRT 79

                          90
                  ....*....|....*.
gi 1227964562 380 VKAGFYSWEKLNNLEL 395
Cdd:cd12647    80 VKASFYDLDRFRRLDL 95

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562  315 VDEDLEPEVKDECNtKYGEVVRVVIFEQPNV--PSDEAVRIFVEFRRIESAIKAVVDLNGRFFGGRQVKA 382
Cdd:smart00361   1 KDEDFERELKEEEE-YFGEVGKINKIYIDDVgyENHKRGNVYITFERSEDAARAIVDLNGRYFDGRLVKA 69

G-patch domain; This domain is found in a number of RNA binding proteins, and is also found in proteins that contain RNA binding domains. This suggests that this domain may have an RNA binding function. This domain has seven highly conserved glycines.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1227964562 212 GGSVAAKIMAKYGFKEGQGLGKQEQGISMALQVEKTSKRGG 252
Cdd:pfam01585   1 TSNIGFKLLQKMGWKEGQGLGKNEQGIAEPIEAKIKKDRRG 41

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 1227964562 312 PGEVDEDlepEVKDECNtKYGEVVRVVIFEQPNVPSDeaVRIFVEFRRIESAIKAVVDLNGRFFGGRQVK 381
Cdd:pfam00076   7 PPDTTEE---DLKDLFS-KFGPIKSIRLVRDETGRSK--GFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in UHM domain of 45 kDa-splicing factor (SPF45) and similar proteins; This subgroup corresponds to the RRM of SPF45, also termed RNA-binding motif protein 17 (RBM17), an RNA-binding protein consisting of an unstructured N-terminal region, followed by a G-patch motif and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors a RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain) and an Arg-Xaa-Phe sequence motif. SPF45 regulates alternative splicing of the apoptosis regulatory gene FAS (also known as CD95). It induces exon 6 skipping in FAS pre-mRNA through the UHM domain that binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) present in the 3' splice site-recognizing factors U2AF65, SF1 and SF3b155.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 300 PSKVVLLRNMVGPGEVDEDLEPEVKDECnTKYGEVVRVVIFEQPNVPSDEAVRIFVEFRRIESAIKAVVDLNGRFFGGRQ 379
Cdd:cd12647     1 PSKVVLLRNMVGPGEVDEDLEPEVKEEC-EKYGKVTKVVIFEIPGAPDDEAVRIFVEFERVESAIKAVVDLNGRFFGGRT 79

                          90
                  ....*....|....*.
gi 1227964562 380 VKAGFYSWEKLNNLEL 395
Cdd:cd12647    80 VKASFYDLDRFRRLDL 95

RNA recognition motif 3 (RRM3) found in UHM domain of poly(U)-binding-splicing factor PUF60 and similar proteins; This subgroup corresponds to the RRM3 of PUF60, also termed FUSE-binding protein-interacting repressor (FBP-interacting repressor or FIR), or Ro-binding protein 1 (RoBP1), or Siah-binding protein 1 (Siah-BP1), an essential splicing factor that functions as a poly-U RNA-binding protein required to reconstitute splicing in depleted nuclear extracts. Its function is enhanced through interaction with U2 auxiliary factor U2AF65. PUF60 also controls human c-myc gene expression by binding and inhibiting the transcription factor far upstream sequence element (FUSE)-binding-protein (FBP), an activator of c-myc promoters. PUF60 contains two central RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a C-terminal U2AF (U2 auxiliary factor) homology motifs (UHM) that harbors another RRM and binds to tryptophan-containing linear peptide motifs (UHM ligand motifs, ULMs) in several nuclear proteins. The research indicates that PUF60 binds FUSE as a dimer, and only the first two RRM domains participate in the single-stranded DNA recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 301 SKVVLLRNMVGPGEVDEDLEPEVKDECnTKYGEVVRVVIFEQPNVPSDEA---VRIFVEFRRIESAIKAVVDLNGRFFGG 377
Cdd:cd12648     1 SRVMVLRNMVGPEDIDDDLEGEVTEEC-GKFGAVNRVIIYQEKQGEEEDAeiiVKIFVEFSMPSEAEKAIQALNGRWFGG 79

                          90
                  ....*....|....*...
gi 1227964562 378 RQVKAGFYSWEKLNNLEL 395
Cdd:cd12648    80 RKVVAELYDQTRFDNSDL 97

RNA recognition motif 3 (RRM3) found in vertebrate RNA-binding protein 39 (RBM39) and similar proteins; This subfamily corresponds to the RRM3 of RBM39, also termed hepatocellular carcinoma protein 1, or RNA-binding region-containing protein 2, or splicing factor HCC1, ia 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. Based on the specific domain composition, RBM39 has been classified into a family of non-snRNP (small nuclear ribonucleoprotein) splicing factors that are usually not complexed to snRNAs.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 301 SKVVLLRNMVGPGE-----VDEDLEPEVKDECNtKYGEVVRVVIFEqpNVPSDEavrIFVEFRRIESAIKAVVDLNGRFF 375
Cdd:cd12285     1 SRCVILKNMFDPAEetednWDDEIKEDVIEECS-KYGPVLHIYVDK--NSPQGN---VYVKFKTIEAAQKCVQAMNGRWF 74

                          90
                  ....*....|.
gi 1227964562 376 GGRQVKAGFYS 386
Cdd:cd12285    75 DGRQITAAYVP 85

RNA recognition motif;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562  315 VDEDLEPEVKDECNtKYGEVVRVVIFEQPNV--PSDEAVRIFVEFRRIESAIKAVVDLNGRFFGGRQVKA 382
Cdd:smart00361   1 KDEDFERELKEEEE-YFGEVGKINKIYIDDVgyENHKRGNVYITFERSEDAARAIVDLNGRYFDGRLVKA 69

G-patch domain; This domain is found in a number of RNA binding proteins, and is also found in proteins that contain RNA binding domains. This suggests that this domain may have an RNA binding function. This domain has seven highly conserved glycines.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1227964562 212 GGSVAAKIMAKYGFKEGQGLGKQEQGISMALQVEKTSKRGG 252
Cdd:pfam01585   1 TSNIGFKLLQKMGWKEGQGLGKNEQGIAEPIEAKIKKDRRG 41

RNA recognition motif 2 (RRM2) found in HIV Tat-specific factor 1 (Tat-SF1) and similar proteins; This subfamily corresponds to the RRM2 of Tat-SF1 and CUS2. Tat-SF1 is the cofactor for stimulation of transcriptional elongation by human immunodeficiency virus-type 1 (HIV-1) Tat. It is a substrate of an associated cellular kinase. Tat-SF1 contains two RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a highly acidic carboxyl-terminal half. The family also includes CUS2, a yeast homolog of human Tat-SF1. CUS2 interacts with U2 RNA in splicing extracts and functions as a splicing factor that aids assembly of the splicing-competent U2 snRNP in vivo. CUS2 also associates with PRP11 that is a subunit of the conserved splicing factor SF3a. Like Tat-SF1, CUS2 contains two RRMs as well.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 302 KVVLLRNMVGPGEVDED------LEPEVKDECNtKYGEVVRVVIFEQ-PnvpsdEAVrIFVEFRRIESAIKAVVDLNGRF 374
Cdd:cd12282     2 KVVILKNMFHPKEFEEDpelineIKEDLREECE-KFGQVKKVVVFDRhP-----DGV-ASVKFKEPEEADKCIQALNGRW 74

                          90
                  ....*....|.
gi 1227964562 375 FGGRQVKAGFY 385
Cdd:cd12282    75 FAGRKLEAETW 85

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 1227964562 304 VLLRNMvgPGEVDEDlepEVKDECNtKYGEVVRVVIFEQPNVPSDEAVriFVEFRRIESAIKAVVDLNGRFFGGRQVK 381
Cdd:cd00590     1 LFVGNL--PPDTTEE---DLRELFS-KFGEVVSVRIVRDRDGKSKGFA--FVEFESPEDAEKALEALNGTELGGRPLK 70

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 1227964562 312 PGEVDEDlepEVKDECNtKYGEVVRVVIFEQPNVPSDeaVRIFVEFRRIESAIKAVVDLNGRFFGGRQVK 381
Cdd:pfam00076   7 PPDTTEE---DLKDLFS-KFGPIKSIRLVRDETGRSK--GFAFVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit-related protein 1 (U2AFBPL) and similar proteins; This subgroup corresponds to the RRM of U2AFBPL, a human homolog of the imprinted mouse gene U2afbp-rs, which encodes a U2 small nuclear ribonucleoprotein auxiliary factor 35 kDa subunit-related protein 1 (U2AFBPL), also termed CCCH type zinc finger, RNA-binding motif and serine/arginine rich protein 1 (U2AF1RS1), or U2 small nuclear RNA auxiliary factor 1-like 1 (U2AF1L1). Although the biological role of U2AFBPL remains unclear, it shows high sequence homology to splicing factor U2AF 35 kDa subunit (U2AF35 or U2AF1) that directly binds to the 3' splice site of the conserved AG dinucleotide and performs multiple functions in the splicing process in a substrate-specific manner. Like U2AF35, U2AFBPL contains two N-terminal zinc fingers, a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal arginine/serine (SR)-rich domain.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 317 EDLEPEVKdecntKYGEVV--RVVIFEQP----NVpsdeavriFVEFRRIESAIKAVVDLNGRFFGGRQV 380
Cdd:cd12540    43 EDVLPEFK-----KFGKVVqfKVCCNSEPhlrgNV--------YVQYQSEEEALKAFTSFNGRWYAGKQL 99

RNA recognition motif 2 (RRM2) found in heterogeneous nuclear ribonucleoprotein L (hnRNP-L) and similar proteins; This subfamily corresponds to the RRM2 of heterogeneous nuclear ribonucleoprotein L (hnRNP-L), heterogeneous nuclear ribonucleoprotein L-like (hnRNP-LL), and similar proteins. hnRNP-L is a higher eukaryotic specific subunit of human KMT3a (also known as HYPB or hSet2) complex required for histone H3 Lys-36 trimethylation activity. It plays both nuclear and cytoplasmic roles in mRNA export of intronless genes, IRES-mediated translation, mRNA stability, and splicing. hnRNP-LL plays a critical and unique role in the signal-induced regulation of CD45 and acts as a global regulator of alternative splicing in activated T cells. It is closely related in domain structure and sequence to hnRNP-L, which contains three RNA-recognition motifs (RRMs), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain).

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1227964562 329 TKYGEVVRVVIFEQPNVPSdeavriFVEFRRIESAIKAVVDLNGR 373
Cdd:cd12694    25 SPYGKVLRIVIFRKNGVQA------MVEFDSVESAQRAKAALNGA 63

RNA recognition motif (RRM) found in U2 small nuclear ribonucleoprotein auxiliary factor U2AF 35 kDa subunit (U2AF35) and similar proteins; This subfamily corresponds to the RRM in U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF) which has been implicated in the recruitment of U2 snRNP to pre-mRNAs. It is a highly conserved heterodimer composed of large and small subunits; this family includes the small subunit of U2AF (U2AF35 or U2AF1) and U2AF 35 kDa subunit B (U2AF35B or C3H60). U2AF35 directly binds to the 3' splice site of the conserved AG dinucleotide and performs multiple functions in the splicing process in a substrate-specific manner. It promotes U2 snRNP binding to the branch-point sequences of introns through association with the large subunit of U2AF (U2AF65 or U2AF2). Although the biological role of U2AF35B remains unclear, it shows high sequence homolgy to U2AF35, which contains two N-terminal zinc fingers, a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal arginine/serine (SR) -rich segment interrupted by glycines. In contrast to U2AF35, U2AF35B has a plant-specific conserved C-terminal region containing SERE motif(s), which may have an important function specific to higher plants.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1227964562 322 EVKDECNtKYGEVVRVVIFEQP------NVpsdeavriFVEFRRIESAIKAVVDLNGRFFGGRQV 380
Cdd:cd12287    40 DVFLELS-RFGEIEDLVVCSNLndhllgNV--------YVKFESEEDAEAALQALNGRYYAGRPL 95

RNA recognition motif (RRM) found in splicing factor U2AF 35 kDa subunit B (U2AF35B); This subgroup corresponds to the RRM of U2AF35B, also termed zinc finger CCCH domain-containing protein 60 (C3H60), which is one of the small subunits of U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF). It has been implicated in the recruitment of U2 snRNP to pre-mRNAs and is a highly conserved heterodimer composed of large and small subunits. Members in this family are mainly found in plant. They show high sequence homology to vertebrates U2AF35 that directly binds to the 3' splice site of the conserved AG dinucleotide and performs multiple functions in the splicing process in a substrate-specific manner. U2AF35B contains two N-terminal zinc fingers, a central RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), and a C-terminal arginine/serine (SR)-rich domain. In contrast to U2AF35, U2AF35B has a plant-specific conserved C-terminal region containing SERE motif(s), which may have an important function specific to higher plants.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1227964562 310 VGPGEVDEDLEPEVKD--ECNTKYGEVvrvvifEQPNVP---SDEAV-RIFVEFRRIESAIKAVVDLNGRFFGGRQVKAG 383
Cdd:cd12539    26 LDPRELQEHFEDFYEDvfEELSKFGEV------EALNVCdnlGDHMVgNVYVKFRDEEHAAAALKALQGRFYAGRPIIVE 99

                  .
gi 1227964562 384 F 384
Cdd:cd12539   100 F 100

RNA recognition motif (RRM) found in cleavage stimulation factor subunit 2 (CSTF2), yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins; This subfamily corresponds to the RRM domain of CSTF2, its tau variant and eukaryotic homologs. CSTF2, also termed cleavage stimulation factor 64 kDa subunit (CstF64), is the vertebrate conterpart of yeast mRNA 3'-end-processing protein RNA15. It is expressed in all somatic tissues and is one of three cleavage stimulatory factor (CstF) subunits required for polyadenylation. CstF64 contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), a CstF77-binding domain, a repeated MEARA helical region and a conserved C-terminal domain reported to bind the transcription factor PC-4. During polyadenylation, CstF interacts with the pre-mRNA through the RRM of CstF64 at U- or GU-rich sequences within 10 to 30 nucleotides downstream of the cleavage site. CSTF2T, also termed tauCstF64, is a paralog of the X-linked cleavage stimulation factor CstF64 protein that supports polyadenylation in most somatic cells. It is expressed during meiosis and subsequent haploid differentiation in a more limited set of tissues and cell types, largely in meiotic and postmeiotic male germ cells, and to a lesser extent in brain. The loss of CSTF2T will cause male infertility, as it is necessary for spermatogenesis and fertilization. Moreover, CSTF2T is required for expression of genes involved in morphological differentiation of spermatids, as well as for genes having products that function during interaction of motile spermatozoa with eggs. It promotes germ cell-specific patterns of polyadenylation by using its RRM to bind to different sequence elements downstream of polyadenylation sites than does CstF64. The family also includes yeast ortholog mRNA 3'-end-processing protein RNA15 and similar proteins. RNA15 is a core subunit of cleavage factor IA (CFIA), an essential transcriptional 3'-end processing factor from Saccharomyces cerevisiae. RNA recognition by CFIA is mediated by an N-terminal RRM, which is contained in the RNA15 subunit of the complex. The RRM of RNA15 has a strong preference for GU-rich RNAs, mediated by a binding pocket that is entirely conserved in both yeast and vertebrate RNA15 orthologs.

                          10        20        30
                  ....*....|....*....|....*....|.
gi 1227964562 354 FVEFRRIESAIKAVVDLNGRFFGGRQVKAGF 384
Cdd:cd12398    46 FCEFRDAETALSAVRNLNGYELNGRPLRVDF 76

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

                          10        20        30
                  ....*....|....*....|....*....|..
gi 1227964562 354 FVEFRRIESAIKAVVDLNGRFFGGRQVKAGFY 385
Cdd:cd12409    50 YAEFSSVEEAEKVVKDLNGKVFKGRKLFVKLH 81

RNA recognition motif 2 (RRM2) found in granule-associated RNA binding proteins p40-TIA-1 and TIAR; This subfamily corresponds to the RRM2 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 1227964562 318 DLEPEVKD----ECNTKYGEV--VRVVIFEQPNVPSDEAvriFVEFRRIESAIKAVVDLNGRFFGGRQVK 381
Cdd:cd12353     6 DLSPEIETedlkEAFAPFGEIsdARVVKDTQTGKSKGYG---FVSFVKKEDAENAIQGMNGQWLGGRNIR 72

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.

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gi 1227964562 315 VDEDLEPEVKDECNTKYGEVVRVVifeqpnVPSDEAVRI----FVEFRRIESAIKAVVDLNGRFFGGRQVKAG 383
Cdd:cd12380     9 FGEDVDDDELKELFEKYGKITSAK------VMKDDSGKSkgfgFVNFENHEAAQKAVEELNGKELNGKKLYVG 75