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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958647214  43 SQTIVLLNLYRNPQNTAQTADGSHCHVSDVEVQEHYDNFFE---------------------------------FRREED 89
Cdd:cd12538     1 SQTILLQNLYQNPQNTPQSADGLKVKVSDVELQEHFDEFYEdvfveleekygeieemnvcdnlgdhlvgnvyvkFRREED 80

                          90       100
                  ....*....|....*....|....
gi 1958647214  90 AERAVAELNNRWFNGQAVHAELSP 113
Cdd:cd12538    81 AEKAVNDLNNRWFNGQPIYAELSP 104

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        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958647214  43 SQTIVLLNLYRNPQNTAQTADGSHCHVSDVEVQEHYDNFFE---------------------------------FRREED 89
Cdd:cd12538     1 SQTILLQNLYQNPQNTPQSADGLKVKVSDVELQEHFDEFYEdvfveleekygeieemnvcdnlgdhlvgnvyvkFRREED 80

                          90       100
                  ....*....|....*....|....
gi 1958647214  90 AERAVAELNNRWFNGQAVHAELSP 113
Cdd:cd12538    81 AEKAVNDLNNRWFNGQPIYAELSP 104

Zinc finger C-x8-C-x5-C-x3-H type (and similar);

                          10        20
                  ....*....|....*....|....*..
gi 1958647214  13 KDKVNCSFYFKIGACRHGDRCSRLHNK 39
Cdd:pfam00642   1 YKTELCRFFLRTGYCKYGDRCKFAHGQ 27

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        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958647214  43 SQTIVLLNLYRNPQNTAQTADGSHCHVSDVEVQEHYDNFFE---------------------------------FRREED 89
Cdd:cd12538     1 SQTILLQNLYQNPQNTPQSADGLKVKVSDVELQEHFDEFYEdvfveleekygeieemnvcdnlgdhlvgnvyvkFRREED 80

                          90       100
                  ....*....|....*....|....
gi 1958647214  90 AERAVAELNNRWFNGQAVHAELSP 113
Cdd:cd12538    81 AEKAVNDLNNRWFNGQPIYAELSP 104

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 1958647214  44 QTIVLLNLYRNPQNTAQTADGSHCHVSDVEVQEHYDNFFE--------------------------------FRREEDAE 91
Cdd:cd12539     1 PTILLSNMYQNPIMNAPLGAAQGIPLDPRELQEHFEDFYEdvfeelskfgevealnvcdnlgdhmvgnvyvkFRDEEHAA 80

                          90       100
                  ....*....|....*....|..
gi 1958647214  92 RAVAELNNRWFNGQAVHAELSP 113
Cdd:cd12539    81 AALKALQGRFYAGRPIIVEFSP 102

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
                  ....*....|....*....|....*....|....*..
gi 1958647214  81 FFEFRREEDAERAVAELNNRWFNGQAVHAELSPVTDF 117
Cdd:cd12648    56 FVEFSMPSEAEKAIQALNGRWFGGRKVVAELYDQTRF 92

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
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1958647214  64 GSHCHVSDVEVQEHYDN------FFEFRREEDAERAVAELNNRWFNGQAVHAE 110
Cdd:cd00590    20 SKFGEVVSVRIVRDRDGkskgfaFVEFESPEDAEKALEALNGTELGGRPLKVS 72

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 1958647214  43 SQTIVLLNLYRNPQNTAQTAD-----------GSHCHVSDVEVQEHYDN---FFEFRREEDAERAVAELNNRWFNGQAVH 108
Cdd:cd12285     1 SRCVILKNMFDPAEETEDNWDdeikedvieecSKYGPVLHIYVDKNSPQgnvYVKFKTIEAAQKCVQAMNGRWFDGRQIT 80

                  ....*
gi 1958647214 109 AELSP 113
Cdd:cd12285    81 AAYVP 85

RNA recognition motif 3 (RRM3) found in U2 large nuclear ribonucleoprotein auxiliary factor U2AF 65 kDa subunit (U2AF65) and similar proteins; This subfamily corresponds to the RRM3 of U2AF65 and dU2AF50. U2AF65, also termed U2AF2, is the large subunit of U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor (U2AF), which has been implicated in the recruitment of U2 snRNP to pre-mRNAs and is a highly conserved heterodimer composed of large and small subunits. U2AF65 specifically recognizes the intron polypyrimidine tract upstream of the 3' splice site and promotes binding of U2 snRNP to the pre-mRNA branchpoint. U2AF65 also plays an important role in the nuclear export of mRNA. It facilitates the formation of a messenger ribonucleoprotein export complex, containing both the NXF1 receptor and the RNA substrate. Moreover, U2AF65 interacts directly and specifically with expanded CAG RNA, and serves as an adaptor to link expanded CAG RNA to NXF1 for RNA export. U2AF65 contains an N-terminal RS domain rich in arginine and serine, followed by a proline-rich segment and three C-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains). The N-terminal RS domain stabilizes the interaction of U2 snRNP with the branch point (BP) by contacting the branch region, and further promotes base pair interactions between U2 snRNA and the BP. The proline-rich segment mediates protein-protein interactions with the RRM domain of the small U2AF subunit (U2AF35 or U2AF1). The RRM1 and RRM2 are sufficient for specific RNA binding, while RRM3 is responsible for protein-protein interactions. The family also includes Splicing factor U2AF 50 kDa subunit (dU2AF50), the Drosophila ortholog of U2AF65. dU2AF50 functions as an essential pre-mRNA splicing factor in flies. It associates with intronless mRNAs and plays a significant and unexpected role in the nuclear export of a large number of intronless mRNAs.

                          10        20        30
                  ....*....|....*....|....*....|
gi 1958647214  81 FFEFRREEDAERAVAELNNRWFNGQAVHAE 110
Cdd:cd12232    60 FVEFEDVEDAQKAQKALAGRKFDGRTVVAS 89

RNA recognition motif 1 (RRM1) found in vertebrate RRM-containing coactivator activator/modulator (CoAA); This subgroup corresponds to the RRM1 of CoAA, also termed RNA-binding protein 14 (RBM14), or paraspeckle protein 2 (PSP2), or synaptotagmin-interacting protein (SYT-interacting protein), a heterogeneous nuclear ribonucleoprotein (hnRNP)-like protein identified as a nuclear receptor coactivator. It mediates transcriptional coactivation and RNA splicing effects in a promoter-preferential manner and is enhanced by thyroid hormone receptor-binding protein (TRBP). CoAA contains two N-terminal RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a TRBP-interacting domain. It stimulates transcription through its interactions with coactivators, such as TRBP and CREB-binding protein CBP/p300, via the TRBP-interacting domain and interaction with an RNA-containing complex, such as DNA-dependent protein kinase-poly(ADP-ribose) polymerase complexes, via the RRMs.

                          10        20        30
                  ....*....|....*....|....*....|..
gi 1958647214  81 FFEFRREEDAERAVAELNNRWFNGQAVHAELS 112
Cdd:cd12608    38 FVHMRGEAAADRAIRELNGRELHGRALVVEES 69

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.

                          10        20        30
                  ....*....|....*....|....*....|..
gi 1958647214  81 FFEFRREEDAERAVAELNNRWFNGQAVHAELS 112
Cdd:cd12373    40 FVEFEDPRDAEDAVRALDGRRICGSRVRVELS 71

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
                  ....*....|....*....|....*..
gi 1958647214  81 FFEFRREEDAERAVAELNNRWFNGQAV 107
Cdd:cd12353    45 FVSFVKKEDAENAIQGMNGQWLGGRNI 71