RING finger (Really Interesting New Gene) domain and U-box domain superfamily; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers: some have different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type RING fingers are closely related to RING-HC fingers. In contrast, C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type RING fingers are more closely related to RING-H2 fingers. However, not all RING finger-containing proteins display regular RING finger features, and the RING finger family has turned out to be multifarious. The degenerate RING fingers of the Siz/PIAS RING (SP-RING) family proteins and sporulation protein RMD5, are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues. They bind only one Zn2+ ion. On the other hand, the RING fingers of the human APC11 and RBX1 proteins can bind a third Zn atom since they harbor four additional Zn ligands. U-box is a modified form of the RING finger domain that lacks metal chelating Cys and His residues. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms. RING finger/U-box-containing proteins are a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enable efficient transfer of ubiquitin from E2 to the substrates.

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                  ....*....|....*....|....*....|....*....|..
gi 1956591424 243 AIVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16530     2 SVSCQVCEHILADPVQTPCKHLFCRTCILKCLKVMGSYCPSC 43

RING finger, HC subclass, found in recombination activating gene-1 (RAG-1) and similar proteins; RAG-1, also known as V(D)J recombination-activating protein 1, RING finger protein 74 (RNF74), or endonuclease RAG1, is the catalytic component of the RAG complex, a multiprotein complex that mediates the DNA cleavage phase during V(D)J recombination. RAG1 is a lymphoid-specific factor that mediates DNA-binding to conserved recombination signal sequences (RSS) and catalyzes DNA cleavage activities by introducing a double-strand break between the RSS and the adjacent coding segment. It also functions as an E3 ubiquitin-protein ligase that mediates monoubiquitination of histone H3, which is required for the joining step of V(D)J recombination. RAG-1 contains an N-terminal C3HC4-type RING-HC finger that mediates monoubiquitylation of histone H3, an adjacent C2H2-type zinc finger, and a nonamer binding (NBD) DNA-binding domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1956591424 243 AIVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16530     2 SVSCQVCEHILADPVQTPCKHLFCRTCILKCLKVMGSYCPSC 43

DNA repair protein rad18; All proteins in this family for which functions are known are involved in nucleotide excision repair.This family is based on the phylogenomic analysis of JA Eisen (1999, Ph.D. Thesis, Stanford University). [DNA metabolism, DNA replication, recombination, and repair]

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1956591424 238 KDFVSAIVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRIlGPQCPAC 284
Cdd:TIGR00599  21 YPLDTSLRCHICKDFFDVPVLTSCSHTFCSLCIRRCLSN-QPKCPLC 66

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1956591424 246 CQVCDHLLSDPVQS-PCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:pfam00097   1 CPICLEEPKDPVTLlPCGHLFCSKCIRSWLESGNVTCPLC 40

RING finger, HC subclass, found in recombination activating gene-1 (RAG-1) and similar proteins; RAG-1, also known as V(D)J recombination-activating protein 1, RING finger protein 74 (RNF74), or endonuclease RAG1, is the catalytic component of the RAG complex, a multiprotein complex that mediates the DNA cleavage phase during V(D)J recombination. RAG1 is a lymphoid-specific factor that mediates DNA-binding to conserved recombination signal sequences (RSS) and catalyzes DNA cleavage activities by introducing a double-strand break between the RSS and the adjacent coding segment. It also functions as an E3 ubiquitin-protein ligase that mediates monoubiquitination of histone H3, which is required for the joining step of V(D)J recombination. RAG-1 contains an N-terminal C3HC4-type RING-HC finger that mediates monoubiquitylation of histone H3, an adjacent C2H2-type zinc finger, and a nonamer binding (NBD) DNA-binding domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1956591424 243 AIVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16530     2 SVSCQVCEHILADPVQTPCKHLFCRTCILKCLKVMGSYCPSC 43

RING finger, HC subclass, found in Saccharomyces cerevisiae DNA repair protein RAD16, Schizosaccharomyces pombe rhp16, and similar proteins; Budding yeast RAD16, also known as ATP-dependent helicase RAD16, is encoded by a yeast excision repair gene homologous to the recombinational repair gene RAD54 and to the SNF2 gene involved in transcriptional activation. It is a component of the global genome repair (GGR) complex that promotes global genome nucleotide excision repair (GG-NER) by removing DNA damage from non-transcribing DNA. RAD16 is involved in differential repair of DNA after UV damage, and repairs preferentially the MAT-alpha locus compared with the HML-alpha locus. Fission yeast rhp16, also known as ATP-dependent helicase rhp16, is a RAD16 homolog. It is involved in GGR via nucleotide excision repair (NER), in conjunction with rhp7, after UV irradiation. Both RAD16 and rhp16 contain a C3HC4-type RING-HC finger, as well as a DEAD-like helicase domain and a helicase superfamily C-terminal domain.

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                  ....*....|....*....|....*....|....*....|....
gi 1956591424 244 IVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILG---PQCPAC 284
Cdd:cd16567     1 LVCGICHEEAEDPVVARCHHVFCRACVKEYIESAPggkVTCPTC 44

Modified RING finger, HC subclass (C3HC3D-type), found in tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) and similar proteins; TRAF6, also known as interleukin-1 signal transducer or RING finger protein 85 (RNF85), is a cytoplasmic adapter protein that mediates signals induced by the tumor necrosis factor receptor (TNFR) superfamily and Toll-like receptor (TLR)/interleukin-1 receptor (IL-1R) family. It functions as a mediator involved in the activation of mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), and interferon regulatory factor pathways, as well as in IL-1R-mediated activation of NF-kappaB. TRAF6 is also an oncogene that plays a vital role in K-RAS-mediated oncogenesis. TRAF6 contains an N-terminal domain with a modified C3HC3D-type RING-HC finger and several zinc fingers, and a C-terminal TRAF domain that comprises a coiled coil domain and a conserved TRAF-C domain.

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                  ....*....|....*....|....*....|....*..
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCP 282
Cdd:cd16643     4 CPICLMALREPVQTPCGHRFCKACILKSIREAGHKCP 40

RING finger, HC subclass, found in tripartite motif-containing protein 8 (TRIM8) and similar proteins; TRIM8, also known as glioblastoma-expressed RING finger protein (GERP) or RING finger protein 27 (RNF27), is a probable E3 ubiquitin-protein ligase that may promote proteasomal degradation of suppressor of cytokine signaling 1 (SOCS1) and further regulate interferon-gamma signaling. It functions as a new p53 modulator that stabilizes p53 impairing its association with MDM2 and inducing the reduction of cell proliferation. TRIM8 deficit dramatically impairs p53 stabilization and activation in response to chemotherapeutic drugs. TRIM8 also modulates tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta)-triggered nuclear factor-kappaB (NF- kappa B) activation by targeting transforming growth factor beta (TGFbeta) activated kinase 1 (TAK1) for K63-linked polyubiquitination. Moreover, TRIM8 modulates translocation of phosphorylated STAT3 into the nucleus through interaction with Hsp90beta and consequently regulates transcription of Nanog in embryonic stem cells. It also interacts with protein inhibitor of activated STAT3 (PIAS3), which inhibits IL-6-dependent activation of STAT3. TRIM8 belongs to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as an uncharacterized region positioned C-terminal to the RBCC domain. The coiled coil domain is required for homodimerization and the region immediately C-terminal to the RING motif is sufficient to mediate the interaction with SOCS1.

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                  ....*....|....*....|....*....|....*....|....*....|..
gi 1956591424 240 FVSAIVCQVCDHLLSDPVQSPCQHLFCRTCI-QKYSRILGP-QCPACGLLFN 289
Cdd:cd16580     8 FEEELICPICLHVFVEPVQLPCKHNFCRGCIgEAWAKDAGLvRCPECNQAYN 59

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 1956591424  246 CQVC-DHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:smart00184   1 CPIClEEYLKDPVILPCGHTFCRSCIRKWLESGNNTCPIC 40

RING finger, HC subclass, found in tripartite motif-containing protein TRIM65 and similar proteins; TRIM65 is an E3 ubiquitin-protein ligase that interacts with the innate immune receptor MDA5, enhancing its ability to stimulate interferon-beta signaling. It functions as a potential oncogenic protein that negatively regulates p53 through ubiquitination, providing insight into the development of novel approaches targeting TRIM65 for non-small cell lung carcinoma (NSCLC) treatment, and also overcoming chemotherapy resistance. Moreover, TRIM65 negatively regulates microRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. TRIM65 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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                  ....*....|....*....|....*....|....*....|....*..
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGP---QCPACGLLFN 289
Cdd:cd16609     6 CSICLGLYQDPVTLPCQHSFCRACIEDHWRQKDEgsfSCPECRAPFP 52

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

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                  ....*....|....*....|....*....|....*....|
gi 1956591424 246 CQVCDHLLSDPVQS-PCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:pfam00097   1 CPICLEEPKDPVTLlPCGHLFCSKCIRSWLESGNVTCPLC 40

second RING finger, HC subclass, found in the LON peptidase N-terminal domain and RING finger protein family; The LON peptidase N-terminal domain and RING finger protein family includes LONRF1 (also known as RING finger protein 191 or RNF191), LONRF2 (also known as RING finger protein 192, RNF192, or neuroblastoma apoptosis-related protease), LONRF3 (also known as RING finger protein 127 or RNF127), which are characterized by containing two C3HC4-type RING-HC fingers, four tetratricopeptide (TPR) repeats, and an ATP-dependent protease La (LON) substrate-binding domain at the C-terminus. Their biological functions remain unclear. This model corresponds to the second RING-HC finger.

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                  ....*....|....*....|....*....|....*....|..
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIqkySRIL--GPQCPACG 285
Cdd:cd16514     4 CSLCLRLLYEPVTTPCGHTFCRACL---ERCLdhSPKCPLCR 42

RING finger, HC subclass, found in helicase-like transcription factor (HLTF) and similar proteins; HLTF, also known as DNA-binding protein/plasminogen activator inhibitor 1 regulator, HIP116, RING finger protein 80, SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 3, or sucrose nonfermenting protein 2-like 3, is a yeast RAD5 homolog found in mammals. It has both E3 ubiquitin ligase and DNA helicase activities, and plays a pivotal role in the template-switching pathway of DNA damage tolerance. It is involved in Lys-63-linked poly-ubiquitination of proliferating cell nuclear antigen (PCNA) at Lys-164 and in the regulation of DNA damage tolerance. It shows double-stranded DNA translocase activity with 3'-5' polarity, thereby facilitating regression of the replication fork. HLTF contains an N-terminal HIRAN (HIP116 and RAD5 N-terminal) domain, a SWI/SNF helicase domain that is divided into N- and C-terminal parts by an insertion of a C3HC4-type RING-HC finger involved in the poly-ubiquitination of PCNA.

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                  ....*....|....*....|....*....|....*....
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16509     6 CAICLDSLTNPVITPCAHVFCRRCICEVIQREKAKCPMC 44

RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1956591424 238 KDFVSAIVCQVCDHLLSDPVQSP-CQHLFCRTCIQKYSR--ILGPQCPACGLLFNPCDLNSPANAFLSILHSL-PLLCQK 313
Cdd:cd16737     5 RDFNPYITCRICKGYLIKPTTVTeCLHTFCKSCIVQHFEdsNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLvPGLRER 84

                          90
                  ....*....|....
gi 1956591424 314 egcgELVRLDSFAD 327
Cdd:cd16737    85 ----ELQREAEFWE 94

Zinc finger, C3HC4 type (RING finger);

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                  ....*....|....*....|....*....|....*....|.
gi 1956591424 245 VCQVCDHLLSDPVQS-PCQHLFCRTCIQKYSRiLGPQCPAC 284
Cdd:pfam13923   1 MCPICMDMLKDPSTTtPCGHVFCQDCILRALR-AGNECPLC 40

RING finger found in Drosophila melanogaster male-specific lethal-2 (MSL2) and similar proteins; MSL2, also known as RING finger protein 184 (RNF184), is a putative DNA-binding protein required for X chromosome dosage compensation in Drosophila males. Its expression is sex specifically regulated by Sex-lethal. Drosophila dosage compensation proteins MOF, MSL1, MSL2, and MSL3 are essential for elevating transcription of the single X chromosome in the male (X chromosome dosage compensation). MSL2 plays a critical role in translation and/or stability of MSL1 in males. In complex with MSL1, it acts as an E3 ubiquitin ligase that promotes ubiquitination of histone H2B. MSL2 contains a C3HC4-type RING-HC finger and a metallothionein-like domain with eight conserved and two non-conserved cysteines, as well as a positively and a negatively charged amino acid residue cluster and a coiled coil domain that may be involved in protein-protein interactions. This subfamily also includes many male-specific lethal-2 homologs from bilaterians.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1956591424 243 AIVCQVCDHLLSDPVQSP---CQHLFCRTCIQKYSRiLGPQCPACG 285
Cdd:cd16522     5 ALSCCVCGQLLVDPIGPTnstCQHNVCKGCKGGKMR-LKPSCSWCK 49

RING finger, HC subclass, found in tripartite motif-containing protein 26 (TRIM26) and similar proteins; TRIM26, also known as acid finger protein (AFP), RING finger protein 95 (RNF95), or zinc finger protein 173 (ZNF173), is an E3 ubiquitin-protein ligase that negatively regulates interferon-beta production and antiviral response through polyubiquitination and degradation of nuclear transcription factor IRF3. It functions as an important regulator for RNA virus-triggered innate immune response by bridging TBK1 to NEMO (NF-kappaB essential modulator, also known as IKKgamma) and mediating TBK1 activation. It also acts as a novel tumor suppressor of hepatocellular carcinoma by regulating cancer cell proliferation, colony forming ability, migration, and invasion. TRIM26 belongs the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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                  ....*....|....*....|....*....|....*....|....*
gi 1956591424 244 IVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILG----PQCPAC 284
Cdd:cd16598     5 VTCSICLDYLRDPVTIDCGHNFCRSCITDYCPISGgherPVCPLC 49

RING finger, HC subclass, found in RING finger protein RNF5, RNF185 and similar proteins; RNF5 and RNF185 are E3 ubiquitin-protein ligases that are anchored to the outer membrane of the endoplasmic reticulum (ER). RNF5 acts at early stages of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) biosynthesis, and functions as a target for therapeutic modalities to antagonize mutant CFTR proteins in CF patients carrying the F508del allele. RNF185 controls the degradation of CFTR and CFTR F508del allele in a RING- and proteasome-dependent manner, but does not control that of other classical endoplasmic reticulum-associated degradation (ERAD) model substrates. Moreover, both RNF5 and RNF185 play important roles in cell adhesion and migration through the modulation of cell migration by ubiquitinating paxillin. Arabidopsis thaliana RING membrane-anchor proteins (AtRMAs) are also included in this family. They possess E3 ubiquitin-protein ligase activity and may play a role in the growth and development of Arabidopsis. All members of this family contain a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|.
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKY--SRILGPQCPAC 284
Cdd:cd16534     3 CNICLDTASDPVVTMCGHLFCWPCLYQWleTRPDRQTCPVC 43

Variant RING finger, HC subclass (C4C4-type), found in retinoblastoma-binding protein 6 (RBBP6) and similar proteins; RBBP6, also known as proliferation potential-related protein, protein P2P-R, retinoblastoma-binding Q protein 1 (RBQ-1), or p53-associated cellular protein of testis (PACT), is a nuclear E3 ubiquitin-protein ligase involved in multiple processes, such as the control of gene expression, mitosis, cell differentiation, and cell apoptosis. It plays a role in both promoting and inhibiting apoptosis in many human cancers, including esophageal, lung, hepatocellular, and colon cancers, familial myeloproliferative neoplasms, as well as in human immunodeficiency virus-associated nephropathy (HIVAN). It functions as an Rb- and p53-binding protein that plays an important role in chaperone-mediated ubiquitination and possibly in protein quality control. It acts as a scaffold protein to promote the assembly of the p53/TP53-MDM2 complex, resulting in an increase of MDM2-mediated ubiquitination and degradation of p53/TP53, and leading to both apoptosis and cell growth. It is also a double-stranded RNA-binding protein that plays a role in mRNA processing by regulating the human polyadenylation machinery and modulating expression of mRNAs with AU-rich 3' untranslated regions (UTRs). Moreover, RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38 that negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Furthermore, RBBP6 is involved in tunicamycin-induced apoptosis by mediating protein kinase (PKR) activation. RBBP6 contains an N-terminal ubiquitin-like domain and a C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger. RBBP6 interacts with chaperones Hsp70 and Hsp40 through its N-terminal ubiquitin-like domain. It promotes the ubiquitination of p53 by Hdm2 in an E4-like manner through its RING finger. It also interacts directly with the pro-proliferative transcription factor Y-box-binding protein-1 (YB-1) via its RING finger.

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                  ....*....|....*....|....*....|....*....|.
gi 1956591424 246 CQVCDHLLSDPVQSPC-QHLFCRTCIQKYSRILGPQCPACG 285
Cdd:cd16620     6 CPICKDLMKDAVLTPCcGNSFCDECIRTALLEEDFTCPTCK 46

RING finger, HC subclass, found in tripartite motif-containing protein TRIM21 and similar proteins; TRIM21, also known as 52 kDa Ro protein, 52 kDa ribonucleoprotein autoantigen Ro/SS-A, Ro(SS-A), RING finger protein 81 (RNF81), or Sjoegren syndrome type A antigen (SS-A), is a ubiquitously expressed E3 ubiquitin-protein ligase and a high affinity antibody receptor uniquely expressed in the cytosol of mammalian cells. As a cytosolic Fc receptor, TRIM21 binds the Fc of virus-associated antibodies and targets the complex in the cytosol for proteasomal degradation in a process known as antibody-dependent intracellular neutralization (ADIN), and provides an intracellular immune response to protect host defense against pathogen infection. It shows remarkably broad isotype specificity as it does not only bind IgG, but also IgM and IgA. Moreover, TRIM21 promotes the cytosolic DNA sensor cGAS and the cytosolic RNA sensor RIG-I sensing of viral genomes during infection by antibody-opsonized virus. It stimulates inflammatory signaling and activates innate transcription factors, such as nuclear factor-kappaB (NF-kappaB). TRIM21 also plays an essential role in p62-regulated redox homeostasis, suggesting it may be a viable target for treating pathological conditions resulting from oxidative damage. Furthermore, TRIM21 may have implications for various autoimmune diseases associated with uncontrolled antiviral signaling through the regulation of Nmi-IFI35 complex-mediated inhibition of innate antiviral response. TRIM21 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1956591424 244 IVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16596    10 VTCPICLDPFVEPVSIECGHSFCQECISQVGKGGGSVCPVC 50

RING finger, HC subclass, found in Arabidopsis thaliana BRCA1-associated RING domain protein 1 (AtBARD1) and similar proteins; AtBARD1, also called protein REPRESSOR OF WUSCHEL 1, binds specifically to H3K4me3 regions of target gene (e.g. WUS and WOX5) promoters to repress their transcription via chromatin remodeling. It is required for the shoot apical meristem (SAM) organization and maintenance, by confining WUS expression to the organizing center, and for the quiescent center (QC) development in the root apical meristem (RAM), by repressing WOX5 expression in the root proximal meristem. AtBARD1 plays a role in DNA repair and in cell-cycle control. It is required for the repair of DNA double-strand breaks (DSBs), both natural and induced by genotoxic stress, by homologous recombination (HR). AtBARD1 contains a typical C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*...
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKySRILGPQCPACGLLFNPCDL 293
Cdd:cd23146     7 CPICLKLLNRPVLLPCDHIFCSSCITD-STKVGSDCPVCKLPYHSQDL 53

RING finger, HC subclass, found in tripartite motif-containing protein 38 (TRIM38) and similar proteins; TRIM38, also known as RING finger protein 15 (RNF15) or zinc finger protein RoRet, is an E3 ubiquitin-protein ligase that promotes K63- and K48-linked ubiquitination of cellular proteins and also catalyzes self-ubiquitination. It negatively regulates Tumor necrosis factor alpha (TNF-alpha)- and interleukin-1beta-triggered Nuclear factor-kappaB (NF-kappaB) activation by mediating lysosomal-dependent degradation of transforming growth factor beta (TGFbeta)-activated kinase 1 (TAK1)-binding protein (TAB)2/3, two critical components of the TAK1 kinase complex. It also inhibits TLR3/4-mediated activation of NF-kappaB and interferon regulatory factor 3 (IRF3) by mediating ubiquitin-proteasomal degradation of TNF receptor-associated factor 6 (Traf6) and NAK-associated protein 1 (Nap1), respectively. Moreover, TRIM38 negatively regulates TLR3-mediated interferon beta (IFN-beta) signaling by targeting ubiquitin-proteasomal degradation of TIR domain-containing adaptor inducing IFN-beta (TRIF). It functions as a valid target for autoantibodies in primary Sjogren's Syndrome. TRIM38 belongs the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQ--------CPACGLLF 288
Cdd:cd16600     8 CSICLQLMTEPVSINCGHSYCKRCIVSFLENQSQLepgletfsCPQCRAPF 58

RING finger, HC subclass, found in tripartite motif-containing protein TRIM25 and similar proteins; TRIM25, also known as estrogen-responsive finger protein (EFP), RING finger protein 147 (RNF147), or RING-type E3 ubiquitin transferase, is an E3 ubiquitin/ISG15 ligase that is induced by estrogen and is therefore particularly abundant in placenta and uterus. TRIM25 regulates various cellular processes through E3 ubiquitin ligase activity, transferring ubiquitin and ISG15 to target proteins. It mediates K63-linked polyubiquitination of retinoic acid inducible gene I (RIG-I) that is crucial for downstream antiviral interferon signaling. It is also required for melanoma differentiation-associated gene 5 (MDA5) and mitochondrial antiviral signaling (MAVS, also known as IPS-1, VISA, Cardiff) mediated activation of nuclear factor-kappaB (NF-kappaB) and interferon production. Upon UV irradiation, TRIM25 interacts with mono-ubiquitinated PCNA and promotes its ISG15 modification (ISGylation), suggesting a crucial role in termination of error-prone translesion DNA synthesis. TRIM25 also functions as a novel regulator of p53 and Mdm2. It enhances p53 and Mdm2 abundance by inhibiting their ubiquitination and degradation in 26S proteasomes. Meanwhile, it inhibits p53's transcriptional activity and dampens the response to DNA damage, and is essential for medaka development and this dependence is rescued by silencing of p53. Moreover, TRIM25 is involved in the host cellular innate immune response against retroviral infection. It interferes with the late stage of feline leukemia virus (FeLV) replication. Furthermore, TRIM25 acts as an oncogene in gastric cancer. Its blockade by RNA interference inhibits migration and invasion of gastric cancer cells through transforming growth factor-beta (TGF-beta) signaling, suggesting it presents a novel target for the detection and treatment of gastric cancer. In addition, TRIM25 acts as an RNA-specific activator for Lin28a/TuT4-mediated uridylation. TRIM25 belongs to the C-IV subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRIL---GPQCPAC 284
Cdd:cd16597     8 CSICLELFKDPVTLPCGHNFCGVCIEKTWDSQhgsEYSCPQC 49

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM13, TRIM59 and similar proteins; TRIM13 and TRIM59, two closely related tripartite motif-containing proteins, belong to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by an N-terminal RBCC (RING, Bbox, and coiled coil) domain, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, followed by a C-terminal transmembrane domain. TRIM13, also known as B-cell chronic lymphocytic leukemia tumor suppressor Leu5, leukemia-associated protein 5, putative tumor suppressor RFP2, RING finger protein 77 (RNF77), or Ret finger protein 2, is an endoplasmic reticulum (ER) membrane anchored E3 ubiquitin-protein ligase that interacts with proteins localized to the ER, including valosin-containing protein (VCP), a protein indispensable for ER-associated degradation (ERAD). TRIM59, also known as RING finger protein 104 (RNF104) or tumor suppressor TSBF-1, is a putative E3 ubiquitin-protein ligase that functions as a novel multiple cancer biomarker for immunohistochemical detection of early tumorigenesis.

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                  ....*....|....*....|....*....|....*....|....*..
gi 1956591424 244 IVCQVCDHLLSDPVQSPCQHLFCRTCIQK------YSRILGPQCPAC 284
Cdd:cd16581     3 LTCSICYNIFDDPKILPCSHTFCKNCLEKllaasgYYLLASLKCPTC 49

RING finger, HC subclass, found in ubiquitin-like PHD and RING finger domain-containing protein 2 (UHRF2); UHRF2, also known as Np95/ICBP90-like RING finger protein (NIRF), Np95-like RING finger protein, nuclear protein 97, nuclear zinc finger protein Np97, RING finger protein 107, or E3 ubiquitin-protein ligase UHRF2, was originally identified as a ubiquitin ligase acting as a small ubiquitin-like modifier (SUMO) E3 ligase that enhances zinc finger protein 131 (ZNF131) SUMOylation, but does not enhance ZNF131 ubiquitination. It also ubiquitinates PCNP, a PEST-containing nuclear protein. Moreover, UHRF2 functions as a nuclear protein involved in cell-cycle regulation and has been implicated in tumorigenesis. It interacts with cyclins, CDKs, p53, pRB, PCNA, HDAC1, DNMTs, G9a, methylated histone H3 lysine 9, and methylated DNA. It interacts with the cyclin E-CDK2 complex, ubiquitinates cyclins D1 and E1, induces G1 arrest, and is involved in the G1/S transition regulation. Furthermore, UHRF2 is a direct transcriptional target of the transcription factor E2F-1 in the induction of apoptosis. It recruits HDAC1 and binds to methyl-CpG. UHRF2 also participates in the maturation of Hepatitis B virus (HBV) through interacting with HBV core protein and promoting its degradation. UHRF2 contains an N-terminal ubiquitin-like domain (UBL), a tandem Tudor domain (TTD), a plant homeodomain (PHD) domain, a SET- and RING-associated (SRA) domain, and a C-terminal C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|
gi 1956591424 245 VCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16770     5 LCICCQELVYQPVTTECQHNVCKSCLQRSFKAEVYTCPAC 44

RING finger, HC subclass, found in BRCA1-associated RING domain protein 1 (BARD-1) and similar proteins; BARD-1 is a critical factor in BRCA1-mediated tumor suppression and may also serve as a target for tumorigenic lesions in some human cancers. It associates with BRCA1 (breast cancer-1) to form a heterodimeric BRCA1/BARD1 complex that is responsible for maintaining genomic stability through nuclear functions involving DNA damage signaling and repair, transcriptional regulation, and cell cycle control. The BRCA1/BARD1 complex catalyzes autoubiquitination of BRCA1 and trans ubiquitination of other protein substrates. Its E3 ligase activity is dramatically reduced in the presence of UBX domain protein 1 (UBXN1). BARD-1 contains an C3HC4-type RING-HC finger that binds BRCA1 at its N-terminus and three tandem ankyrin repeats and tandem BRCT repeat domains at its C-terminus. The BRCT repeats bind CstF-50 (cleavage stimulation factor) to modulate mRNA processing and RNAP II stability in response to DNA damage.

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                  ....*....|....*....|....*....|....*....|
gi 1956591424 246 CQVCDHLLSDPVQ-SPCQHLFCRTCIQKYsriLGPQCPAC 284
Cdd:cd16496    18 CSRCASILKEPVTlGGCEHVFCRSCVGDR---LGNGCPVC 54

RING finger, HC subclass, found in ligand of numb protein X 3 (LNX3); LNX3, also known as PDZ domain-containing RING finger protein 3 (PDZRN3), or Semaphorin cytoplasmic domain-associated protein 3 (SEMACAP3), is an E3 ubiquitin-protein ligase that was first identified as a Semaphorin-binding partner. It is also responsible for the ubiquitination and degradation of Numb, a component of the Notch signaling pathway that functions in the specification of cell fates during development and is known to control cell numbers during neurogenesis in vertebrates. LNX3 acts as a negative regulator of osteoblast differentiation by inhibiting Wnt-beta-catenin signaling. LNX3 also plays an important role in neuromuscular junction formation. It interacts with and ubiquitinates the muscle specific tyrosine kinase (MuSK), thus promoting its endocytosis and negatively regulating the cell surface expression of this key regulator of postsynaptic assembly. LNX3 contains an N-terminal C3HC4-type RING-HC finger, two PDZ domains, and a C-terminal LNX3 homology (LNX3H) domain.

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                  ....*....|....*....|....*
gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCI 270
Cdd:cd16718     7 CNLCNKVLEDPLTTPCGHVFCAGCV 31

RING finger, HC subclass, found in RING finger protein 213 (RNF213) and similar proteins; RNF213, also known as ALK lymphoma oligomerization partner on chromosome 17 or Moyamoya steno-occlusive disease-associated AAA+ and RING finger protein (mysterin), is an intracellular soluble protein that functions as an E3 ubiquitin-protein ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. It plays a unique role in endothelial cells for proper gene expression in response to inflammatory signals from the environment. Mutations in RNF213 may be associated with Moyamoya disease (MMD), an idiopathic cerebrovascular occlusive disorder prevalent in East Asia. It also acts as a nuclear marker for acanthomorph phylogeny. RNF213 contains two tandem enzymatically active AAA+ ATPase modules and a C3HC4-type RING-HC finger. It can form a huge ring-shaped oligomeric complex.

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gi 1956591424 246 CQVCDHLLSDPVQSPCQHLFCRTCIQKYSRIlGPQCPAC 284
Cdd:cd16561     5 CSICLEDLNDPVKLPCDHVFCEECIRQWLPG-QMSCPLC 42

RING finger, HC subclass, found in Saccharomyces cerevisiae radiation sensitivity protein 18 (RAD18) and similar proteins; RAD18, also called RING-type E3 ubiquitin transferase RAD18, acts as a postreplication repair E3 ubiquitin-protein ligase that associates with the E2 ubiquitin conjugating enzyme UBC2/RAD6 to form the UBC2-RAD18 ubiquitin ligase complex involved in postreplicative repair (PRR) of damaged DNA. The UBC2-RAD18 complex cooperates with RAD5 and the UBC13-MMS2 dimer to attach mono-ubiquitin chains on 'Lys-164' of POL30, which is necessary for PRR. The UBC2-RAD18 complex is also involved in prevention of spontaneous mutations caused by 7,8-dihydro-8-oxoguanine. RAD18 is an E3 RING-finger protein belonging to the UBC2/RAD6 epistasis group. It contains a typical C3HC4-type RING-HC finger.

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gi 1956591424 243 AIVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRIlGPQCPAC 284
Cdd:cd23148     3 ALRCHICKDLLKAPMRTPCNHTFCSFCIRTHLNN-DARCPLC 43

Modified RING finger, HC subclass (C4C4-type), found in tripartite motif-containing protein 37 (TRIM37) and similar proteins; TRIM37, also known as mulibrey nanism protein, or MUL, is a peroxisomal E3 ubiquitin-protein ligase that is involved in the tumorigenesis of several cancer types, including pancreatic ductal adenocarcinoma (PDAC), hepatocellular carcinoma (HCC), breast cancer, and sporadic fibrothecoma. It mono-ubiquitinates histone H2A, a chromatin modification associated with transcriptional repression. Moreover, TRIM37 possesses anti-HIV-1 activity, and interferes with viral DNA synthesis. Mutations in the human TRIM37 gene (also known as MUL) cause Mulibrey (muscle-liver-brain-eye) nanism, a rare growth disorder of prenatal onset characterized by dysmorphic features, pericardial constriction, and hepatomegaly. TRIM37 belongs to the C-VIII subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a MATH (meprin and TRAF-C homology) domain positioned C-terminal to the RBCC domain. Its MATH domain has been shown to interact with the TRAF (TNF-Receptor-Associated Factor) domain of six known TRAFs in vitro.

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                  ....*....|....*....|....*....|....*....|
gi 1956591424 246 CQVCDHLLSDPVQSP-CQHLFCRTCIQKYSRILGPQCPAC 284
Cdd:cd16619     3 CFICMEKLRDPRLCPhCSKLFCKGCIRRWLSEQRSSCPHC 42

RING finger, HC subclass, found in Ret finger protein-like 4B (RFPL4B) and similar proteins; RFPL4B, also called RING finger protein 211 (RNF211), is an uncharacterized RING finger protein containing a typical C3HC4-type RING-HC finger.

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gi 1956591424 244 IVCQVCDHLLSDPVQSPCQHLFCRTCIQKYSRI---LGPQCPAC 284
Cdd:cd16623     9 ATCPICLDFFSHPISLSCAHIFCFDCIQKWMTKredSILTCPLC 52