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 2065622950 246 GGTVAHKIMQKYGFREGQGLGKHEQGLSTALSVEKTSKRGGKIIV 290
Cdd:pfam01585   1 TSNIGFKLLQKMGWKEGQGLGKNEQGIAEPIEAKIKKDRRGLGAE 45

poly-U binding splicing factor, half-pint family; The proteins represented by this model contain three RNA recognition motifs (rrm: pfam00076) and have been characterized as poly-pyrimidine tract binding proteins associated with RNA splicing factors. In the case of PUF60 (GP|6176532), in complex with p54, and in the presence of U2AF, facilitates association of U2 snRNP with pre-mRNA.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 316 KNPTKVVLLRNMVGAGEVDDDLEGETKEECEKYGKVTKCVIFEIPGAPDDEA---VRIFVEFERVESAIKAVVDLNGRYF 392
Cdd:TIGR01645 511 TNRSNVIVLRNMVTPQDIDEFLEGEIREECGKFGVVDRVIINFEKQGEEEDAeiiVKIFVEFSDSMEVDRAKAALDGRFF 590

                          90       100
                  ....*....|....*....|
gi 2065622950 393 GGRVVKASFYNLDKFRQLDL 412
Cdd:TIGR01645 591 GGRTVVAEAYDQILFDHADL 610

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 2065622950 246 GGTVAHKIMQKYGFREGQGLGKHEQGLSTALSVEKTSKRGGKIIV 290
Cdd:pfam01585   1 TSNIGFKLLQKMGWKEGQGLGKNEQGIAEPIEAKIKKDRRGLGAE 45

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2065622950 334 DDDLegetKEECEKYGKVTKC-VIFEIPGAPDDEAvriFVEFERVESAIKAVVDLNGRYFGGRVVK 398
Cdd:pfam00076  12 EEDL----KDLFSKFGPIKSIrLVRDETGRSKGFA---FVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in UHM domain of 45 kDa-splicing factor (SPF45) and similar proteins; This subfamily corresponds to the RRM found in UHM domain of 45 kDa-splicing factor (SPF45 or RBM17), poly(U)-binding-splicing factor PUF60 (FIR or Hfp or RoBP1 or Siah-BP1), and similar proteins. SPF45 is 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. PUF60 is 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 RRMs and a C-terminal UHM domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 319 TKVVLLRNMVGAGEVDDDLEGETKEECEKYGKVTKCVIFEIPGAPDDEAVRIFVEFERVESAIKAVVDLNGRYFGGRVVK 398
Cdd:cd12374     1 TKILVLRNMVGPGEIDEDLKDEIKEECSKYGKVLNVIIHEVASSEADDAVRVFVEFEDADEAIKAFRALNGRFFGGRKVK 80

                  ....*
gi 2065622950 399 ASFYN 403
Cdd:cd12374    81 ARFYD 85

poly-U binding splicing factor, half-pint family; The proteins represented by this model contain three RNA recognition motifs (rrm: pfam00076) and have been characterized as poly-pyrimidine tract binding proteins associated with RNA splicing factors. In the case of PUF60 (GP|6176532), in complex with p54, and in the presence of U2AF, facilitates association of U2 snRNP with pre-mRNA.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 316 KNPTKVVLLRNMVGAGEVDDDLEGETKEECEKYGKVTKCVIFEIPGAPDDEA---VRIFVEFERVESAIKAVVDLNGRYF 392
Cdd:TIGR01645 511 TNRSNVIVLRNMVTPQDIDEFLEGEIREECGKFGVVDRVIINFEKQGEEEDAeiiVKIFVEFSDSMEVDRAKAALDGRFF 590

                          90       100
                  ....*....|....*....|
gi 2065622950 393 GGRVVKASFYNLDKFRQLDL 412
Cdd:TIGR01645 591 GGRTVVAEAYDQILFDHADL 610

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 2065622950 319 TKVVLLRNMVGAGE-----VDDDLEGETKEECEKYGKVTKCVIFEipGAPDDEavrIFVEFERVESAIKAVVDLNGRYFG 393
Cdd:cd12285     1 SRCVILKNMFDPAEetednWDDEIKEDVIEECSKYGPVLHIYVDK--NSPQGN---VYVKFKTIEAAQKCVQAMNGRWFD 75

                  ....*....
gi 2065622950 394 GRVVKASFY 402
Cdd:cd12285    76 GRQITAAYV 84

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 2065622950 246 GGTVAHKIMQKYGFREGQGLGKHEQGLSTALSVEKTSKRGGKIIV 290
Cdd:pfam01585   1 TSNIGFKLLQKMGWKEGQGLGKNEQGIAEPIEAKIKKDRRGLGAE 45

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 318 PTKVVLLRNMVGAGEVDDDLEGE-----TKEECEKYGKVTKCVIFE-IPGAPDDEAV-RIFVEFERVESAIKAVVDLNGR 390
Cdd:TIGR01642 408 PTKVVQLTNLVTGDDLMDDEEYEeiyedVKTEFSKYGPLINIVIPRpNGDRNSTPGVgKVFLEYADVRSAEKAMEGMNGR 487

                          90       100
                  ....*....|....*....|.
gi 2065622950 391 YFGGRVVKASFYNLDKFRQLD 411
Cdd:TIGR01642 488 KFNDRVVVAAFYGEDCYKAGD 508

splicing factor, CC1-like family; This model represents a subfamily of RNA splicing factors including the Pad-1 protein (N. crassa), CAPER (M. musculus) and CC1.3 (H.sapiens). These proteins are characterized by an N-terminal arginine-rich, low complexity domain followed by three (or in the case of 4 H. sapiens paralogs, two) RNA recognition domains (rrm: pfam00706). These splicing factors are closely related to the U2AF splicing factor family (TIGR01642). A homologous gene from Plasmodium falciparum was identified in the course of the analysis of that genome at TIGR and was included in the seed.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 301 AATKKTEANPLTEILKNPTKVVLLRNMVGAGE-----VDDDLEGETKEECEKYGKVTKcVIFEIPGAPDDeavrIFVEFE 375
Cdd:TIGR01622 381 ILKPKAETSFVPVNVNLASRCLVLSNMFDPATeeepnWDKEIEDDVREECSKYGGVVH-IYVDDKNSAGD----IYLKFD 455

                          90       100       110
                  ....*....|....*....|....*....|....*..
gi 2065622950 376 RVESAIKAVVDLNGRYFGGRVVKASFYNLDKFRQLDL 412
Cdd:TIGR01622 456 SVQAAEAAIKALNGRYFGGKMITAAFVVDAVYSKSRL 492

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2065622950 334 DDDLegetKEECEKYGKVTKC-VIFEIPGAPDDEAvriFVEFERVESAIKAVVDLNGRYFGGRVVK 398
Cdd:pfam00076  12 EEDL----KDLFSKFGPIKSIrLVRDETGRSKGFA---FVEFEDEEDAEKAIEALNGKELGGRELK 70

RNA recognition motif (RRM) found in U2AF homology motif kinase 1 (UHMK1) and similar proteins; This subgroup corresponds to the RRM of UHMK1. UHMK1, also termed kinase interacting with stathmin (KIS) or P-CIP2, is a serine/threonine protein kinase functionally related to RNA metabolism and neurite outgrowth. It contains an N-terminal kinase domain and a C-terminal RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain), with high homology to the corresponding motif of the mammalian U2 small nuclear ribonucleoprotein auxiliary factor U2AF 65 kDa subunit (U2AF65 or U2AF2). UHMK1 targets two key regulators of cell proliferation and migration, the cyclin-dependent kinase (CDK) inhibitor p27Kip1 and the microtubule-destabilizing protein stathmin. It plays a critical role during vascular wound repair by preventing excessive vascular smooth muscle cell (VSMC) migration into the vascular lesion. Moreover, UHMK1 may control cell migration and neurite outgrowth by interacting with and phosphorylating the splicing factor SF1, thereby probably contributing to the control of protein expression. Furthermore, UHMK1 may be functionally related to microtubule dynamics and axon development. It localizes to RNA granules, interacts with three proteins found in RNA granules (KIF3A, NonO, and eEF1A), and further enhances the local translation. UHMK1 is highly expressed in regions of the brain implicated in schizophrenia and may play a role in susceptibility to schizophrenia.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 318 PTKVVLLRNMV------GAGEVDDDLEgETKEECEKYGKVTKCVI-FEIPGAPddeavRIFVEFERVESAIKAVVDLNGR 390
Cdd:cd12465     2 PTPVLRLLNVIddsylqSEEEYEDIVE-DVREECQKYGPVVSLLIpKENPGKG-----QVFVEYANAGDSKAAQKMLTGR 75

                          90
                  ....*....|..
gi 2065622950 391 YFGGRVVKASFY 402
Cdd:cd12465    76 MFDGKFVVATFY 87

RNA recognition motif (RRM) found in Eukaryotic CCR4-NOT transcription complex subunit 4 (NOT4) and similar proteins; This subfamily corresponds to the RRM of NOT4, also termed CCR4-associated factor 4, or E3 ubiquitin-protein ligase CNOT4, or potential transcriptional repressor NOT4Hp, a component of the CCR4-NOT complex, a global negative regulator of RNA polymerase II transcription. NOT4 functions as an ubiquitin-protein ligase (E3). It contains an N-terminal C4C4 type RING finger motif, followed by a RNA recognition motif (RRM), also termed RBD (RNA binding domain) or RNP (ribonucleoprotein domain). The RING fingers may interact with a subset of ubiquitin-conjugating enzymes (E2s), including UbcH5B, and mediate protein-protein interactions. T

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 347 KYGKVTKCVI-----FEIPGAPddeAVRIFVEFERVESAIKAVVDLNGRYFGGRVVKASF 401
Cdd:cd12438    31 QYGKIKKIVInrstsYAGSQGP---SASAYVTYSRKEDALRAIQAVDGFVLDGRTLKASF 87

RNA recognition motif (RRM) found in U2 small nuclear ribonucleoprotein auxiliary factor U2AF 35 kDa subunit (U2AF35); This subgroup corresponds to the RRM of U2AF35, also termed U2AF1, 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. 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 (also termed U2AF2). U2AF35 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. U2AF35 binds both U2AF65 and the pre-mRNA through its RRM domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2065622950 343 EECEKYGKVTKCVIFEIPGapdDEAV-RIFVEFERVESAIKAVVDLNGRYFGGRVVKA 399
Cdd:cd12538    46 ELEEKYGEIEEMNVCDNLG---DHLVgNVYVKFRREEDAEKAVNDLNNRWFNGQPIYA 100

RNA recognition motif 3 (RRM3) found in ribonucleoprotein PTB-binding raver-1, raver-2 and similar proteins; This subfamily corresponds to the RRM3 of raver-1 and raver-2. Raver-1 is a ubiquitously expressed heterogeneous nuclear ribonucleoprotein (hnRNP) that serves as a co-repressor of the nucleoplasmic splicing repressor polypyrimidine tract-binding protein (PTB)-directed splicing of select mRNAs. It shuttles between the cytoplasm and the nucleus and can accumulate in the perinucleolar compartment, a dynamic nuclear substructure that harbors PTB. Raver-1 also modulates focal adhesion assembly by binding to the cytoskeletal proteins, including alpha-actinin, vinculin, and metavinculin (an alternatively spliced isoform of vinculin) at adhesion complexes, particularly in differentiated muscle tissue. Raver-2 is a novel member of the heterogeneous nuclear ribonucleoprotein (hnRNP) family. It shows high sequence homology to raver-1. Raver-2 exerts a spatio-temporal expression pattern during embryogenesis and is mainly limited to differentiated neurons and glia cells. Although it displays nucleo-cytoplasmic shuttling in heterokaryons, raver2 localizes to the nucleus in glia cells and neurons. Raver-2 can interact with PTB and may participate in PTB-mediated RNA-processing. However, there is no evidence indicating that raver-2 can bind to cytoplasmic proteins. Both, raver-1 and raver-2, contain three N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), two putative nuclear localization signals (NLS) at the N- and C-termini, a central leucine-rich region, and a C-terminal region harboring two [SG][IL]LGxxP motifs. They binds to RNA through the RRMs. In addition, the two [SG][IL]LGxxP motifs serve as the PTB-binding motifs in raver1. However, raver-2 interacts with PTB through the SLLGEPP motif only.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 2065622950 346 EKYGKVTKCVIFEIPGAPDDEAvriFVEFERVESAIKAVVDLNGRYFGGRVVKASFYN 403
Cdd:cd12390    25 SQVGKPTFCQLAMGNGVPRGFA---FVEFASAEDAEEAQQLLNGHDLQGSPIRVSFGN 79

RNA recognition motif 3 (RRM3) found in heterogeneous nuclear ribonucleoprotein R (hnRNP R) and similar proteins; This subfamily corresponds to the RRM3 in hnRNP R, hnRNP Q, and APOBEC-1 complementation factor (ACF). hnRNP R is a ubiquitously expressed nuclear RNA-binding protein that specifically bind mRNAs with a preference for poly(U) stretches and has been implicated in mRNA processing and mRNA transport, and also acts as a regulator to modify binding to ribosomes and RNA translation. hnRNP Q is also a ubiquitously expressed nuclear RNA-binding protein. It has been identified as a component of the spliceosome complex, as well as a component of the apobec-1 editosome, and has been implicated in the regulation of specific mRNA transport. ACF is an RNA-binding subunit of a core complex that interacts with apoB mRNA to facilitate C to U RNA editing. It may also act as an apoB mRNA recognition factor and chaperone and play a key role in cell growth and differentiation. This family also includes two functionally unknown RNA-binding proteins, RBM46 and RBM47. All members contain three conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2065622950 320 KVVLLRNMVgagevDDDLEGETKEECEKYGKVTKCVIFEipgapdDEAvriFVEFERVESAIKAVVDLNGRYFGGRVVKA 399
Cdd:cd12251     2 KVLYVRNLM-----LSTTEEKLRELFSEYGKVERVKKIK------DYA---FVHFEERDDAVKAMEEMNGKELEGSEIEV 67

                  ..
gi 2065622950 400 SF 401
Cdd:cd12251    68 SL 69

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 2065622950 334 DDDLegetKEECEKYGKVTKcviFEIPGAPDDEAVRI-FVEFERVESAIKAVVDLNGRYFGGRVV 397
Cdd:cd12414    13 EDDL----KKLFSKFGKVLE---VTIPKKPDGKLRGFaFVQFTNVADAAKAIKGMNGKKIKGRPV 70

RNA recognition motif 4 (RRM4) found in SMART/HDAC1-associated repressor protein (SHARP) and similar proteins; This subfamily corresponds to the RRM of SHARP, also termed Msx2-interacting protein (MINT), or SPEN homolog, is an estrogen-inducible transcriptional repressor that interacts directly with the nuclear receptor corepressor SMRT, histone deacetylases (HDACs) and components of the NuRD complex. SHARP recruits HDAC activity and binds to the steroid receptor RNA coactivator SRA through four conserved N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), further suppressing SRA-potentiated steroid receptor transcription activity. Thus, SHARP has the capacity to modulate both liganded and nonliganded nuclear receptors. SHARP also has been identified as a component of transcriptional repression complexes in Notch/RBP-Jkappa signaling pathways. In addition to the N-terminal RRMs, SHARP possesses a C-terminal SPOC domain (Spen paralog and ortholog C-terminal domain), which is highly conserved among Spen proteins.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2065622950 347 KYGKVTKCVIfeipgapDDEAVRIFVEFERVESAIKAVVDLNGRYFGGRVVKASF 401
Cdd:cd12351    30 RYGPVVKVVI-------DRQKGMALVLYDEVECAQAAVKETKGRKIGGRKIQVDF 77

RNA recognition motif (RRM) found in polypyrimidine tract-binding protein 1 (PTB or hnRNP I), heterogeneous nuclear ribonucleoprotein L (hnRNP-L), and similar proteins; This subfamily corresponds to the RRM2 of polypyrimidine tract-binding protein 1 (PTB or hnRNP I), polypyrimidine tract-binding protein 2 (PTBP2 or nPTB), regulator of differentiation 1 (Rod1), heterogeneous nuclear ribonucleoprotein L (hnRNP-L), heterogeneous nuclear ribonucleoprotein L-like (hnRNP-LL), polypyrimidine tract-binding protein homolog 3 (PTBPH3), polypyrimidine tract-binding protein homolog 1 and 2 (PTBPH1 and PTBPH2), and similar proteins, and RRM3 of PTBPH1 and PTBPH2. PTB is an important negative regulator of alternative splicing in mammalian cells and also functions at several other aspects of mRNA metabolism, including mRNA localization, stabilization, polyadenylation, and translation. PTBP2 is highly homologous to PTB and is perhaps specific to the vertebrates. Unlike PTB, PTBP2 is enriched in the brain and in some neural cell lines. It binds more stably to the downstream control sequence (DCS) RNA than PTB does but is a weaker repressor of splicing in vitro. PTBP2 also greatly enhances the binding of two other proteins, heterogeneous nuclear ribonucleoprotein (hnRNP) H and KH-type splicing-regulatory protein (KSRP), to the DCS RNA. The binding properties of PTBP2 and its reduced inhibitory activity on splicing imply roles in controlling the assembly of other splicing-regulatory proteins. Rod1 is a mammalian polypyrimidine tract binding protein (PTB) homolog of a regulator of differentiation in the fission yeast Schizosaccharomyces pombe, where the nrd1 gene encodes an RNA binding protein negatively regulates the onset of differentiation. ROD1 is predominantly expressed in hematopoietic cells or organs. It might play a role controlling differentiation in mammals. 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 protein 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. This family also includes polypyrimidine tract binding protein homolog 3 (PTBPH3) found in plant. Although its biological roles remain unclear, PTBPH3 shows significant sequence similarity to other family members, all of which contain four RNA recognition motifs (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain). Although their biological roles remain unclear, both PTBPH1 and PTBPH2 show significant sequence similarity to PTB. However, in contrast to PTB, they have three RRMs.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 2065622950 347 KYGKVTKCVIFEipgapDDEAVRIFVEFERVESAIKAVVDLNGR 390
Cdd:cd12422    24 PYGAVEKIVIFE-----KGTGVQALVQFDSVESAEAAKKALNGR 62

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 2065622950 371 FVEFERVESAIKAVVDLNGRYFGGRVVKASF 401
Cdd:cd12398    46 FCEFRDAETALSAVRNLNGYELNGRPLRVDF 76

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

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2065622950 333 VDDDLEGET-KEECEKYGKVTKCVIFEipgapdDEAVRI----FVEFERVESAIKAVVDLNGRYFGGR 395
Cdd:cd12381     9 LDDTIDDEKlREEFSPFGTITSAKVMT------DEGGRSkgfgFVCFSSPEEATKAVTEMNGRIIGGK 70