RING finger, HC subclass, found in RING finger protein 4 (RNF4) and similar proteins; RNF4, also known as small nuclear ring finger protein (SNURF), is a SUMO-targeted E3 ubiquitin-protein ligase with a pivotal function in the DNA damage response (DDR) by interacting with the deubiquitinating enzyme ubiquitin-specific protease 11 (USP11), a known DDR-component, and further facilitating DNA repair. It plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. Moreover, RNF4 is responsible for the UbcH5A-catalyzed formation of K48 chains that target SUMO-modified promyelocytic leukemia (PML) protein for proteasomal degradation in response to arsenic treatment. It also interacts with telomeric repeat binding factor 2 (TRF2) in a small ubiquitin-like modifier (SUMO)-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination through SUMO-interacting motifs (SIMs). Furthermore, RNF4 can form a complex with a Ubc13-ubiquitin conjugate and Ube2V2. It catalyzes K63-linked polyubiquitination by the Ube2V2-Ubc13 (ubiquitin-loaded) complex. Meanwhile, RNF4 negatively regulates nuclear factor kappa B (NF-kappaB) signaling by down-regulating transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1)-TAK1-binding protein2 (TAB2). RNF4 contains four SIMs followed by a C3HC4-type RING-HC finger at the C-terminus.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4506561  127 SGTVSCPICMDGYSEIVQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHK 183
Cdd:cd16533   1 SGTVSCPICMDGYSEIVQSGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKLNHK 57

RING finger, HC subclass, found in RING finger protein 4 (RNF4) and similar proteins; RNF4, also known as small nuclear ring finger protein (SNURF), is a SUMO-targeted E3 ubiquitin-protein ligase with a pivotal function in the DNA damage response (DDR) by interacting with the deubiquitinating enzyme ubiquitin-specific protease 11 (USP11), a known DDR-component, and further facilitating DNA repair. It plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. Moreover, RNF4 is responsible for the UbcH5A-catalyzed formation of K48 chains that target SUMO-modified promyelocytic leukemia (PML) protein for proteasomal degradation in response to arsenic treatment. It also interacts with telomeric repeat binding factor 2 (TRF2) in a small ubiquitin-like modifier (SUMO)-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination through SUMO-interacting motifs (SIMs). Furthermore, RNF4 can form a complex with a Ubc13-ubiquitin conjugate and Ube2V2. It catalyzes K63-linked polyubiquitination by the Ube2V2-Ubc13 (ubiquitin-loaded) complex. Meanwhile, RNF4 negatively regulates nuclear factor kappa B (NF-kappaB) signaling by down-regulating transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1)-TAK1-binding protein2 (TAB2). RNF4 contains four SIMs followed by a C3HC4-type RING-HC finger at the C-terminus.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4506561  127 SGTVSCPICMDGYSEIVQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHK 183
Cdd:cd16533   1 SGTVSCPICMDGYSEIVQSGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKLNHK 57

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 4506561     132 CPICMDGYSEivqngrLIVSTECGHVFCSQCLRDSLKNAN-TCPTC 176
Cdd:smart00184   1 CPICLEEYLK------DPVILPCGHTFCRSCIRKWLESGNnTCPIC 40

N1R/p28-like protein; Provisional

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 4506561   132 CPICMDG-YSEIVQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKK 179
Cdd:PHA02929 177 CAICMEKvYDKEIKNMYFGILSNCNHVFCIECIDIWKKEKNTCPVCRTP 225

RING finger, HC subclass, found in RING finger protein 4 (RNF4) and similar proteins; RNF4, also known as small nuclear ring finger protein (SNURF), is a SUMO-targeted E3 ubiquitin-protein ligase with a pivotal function in the DNA damage response (DDR) by interacting with the deubiquitinating enzyme ubiquitin-specific protease 11 (USP11), a known DDR-component, and further facilitating DNA repair. It plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. Moreover, RNF4 is responsible for the UbcH5A-catalyzed formation of K48 chains that target SUMO-modified promyelocytic leukemia (PML) protein for proteasomal degradation in response to arsenic treatment. It also interacts with telomeric repeat binding factor 2 (TRF2) in a small ubiquitin-like modifier (SUMO)-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination through SUMO-interacting motifs (SIMs). Furthermore, RNF4 can form a complex with a Ubc13-ubiquitin conjugate and Ube2V2. It catalyzes K63-linked polyubiquitination by the Ube2V2-Ubc13 (ubiquitin-loaded) complex. Meanwhile, RNF4 negatively regulates nuclear factor kappa B (NF-kappaB) signaling by down-regulating transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1)-TAK1-binding protein2 (TAB2). RNF4 contains four SIMs followed by a C3HC4-type RING-HC finger at the C-terminus.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 4506561  127 SGTVSCPICMDGYSEIVQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHK 183
Cdd:cd16533   1 SGTVSCPICMDGYSEIVQSGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKLNHK 57

Modified RING finger, C3HGC3-type, found in RING finger and WD repeat domain-containing protein 3 (RFWD3) and similar proteins; RFWD3, also known as RING finger protein 201 (RNF201) or FLJ10520, is an E3 ubiquitin-protein ligase that forms a complex with Mdm2 and p53 to synergistically ubiquitinate p53 and acts as a positive regulator of p53 stability in response to DNA damage. It is phosphorylated by checkpoint kinase ATM/ATR and the phosphorylation mutant fails to stimulate p53 ubiquitination. RFWD3 also functions as a novel replication protein A (RPA)-associated protein involved in DNA replication checkpoint control. RFWD3 contains an N-terminal SQ-rich region followed by a RING finger domain that exhibits robust E3 ubiquitin ligase activity toward p53, a coiled-coil domain and three WD40 repeats in the C-terminus, the latter two of which may be responsible for protein-protein interaction. The RING finger in this family is a modified C3HGC3-type RING finger, but not a canonical C3H2C3-type RING-H2 finger or C3HC4-type RING-HC finger.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 4506561  129 TVSCPICMDGYSeIVQNGRlIVSTECGHVFCSQCLRDSLKNAN-TCPTCRKKINHKRYHPIY 189
Cdd:cd16450   2 GNTCPICFEPWT-SSGEHR-LVSLKCGHLFGYSCIEKWLKGKGkKCPQCNKKAKRSDIRPLY 61

RING finger, HC subclass, found in really interesting new gene proteins RING1, RING2 and similar proteins; RING1, also known as polycomb complex protein RING1, RING finger protein 1 (RNF1), or RING finger protein 1A (RING1A), is a transcriptional repressor that is associated with the Polycomb group (PcG) protein complex involved in stable repression of gene activity. RING2, also known as huntingtin-interacting protein 2-interacting protein 3, HIP2-interacting protein 3, protein DinG, RING finger protein 1B (RING1B), RING finger protein 2 (RNF2), or RING finger protein BAP-1, is an E3 ubiquitin-protein ligase that interacts with both nucleosomal DNA and an acidic patch on histone H4 to achieve the specific monoubiquitination of K119 on histone H2A (H2AK119ub), thereby playing a central role in histone code and gene regulation. Both RING1 and RING2 are core components of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. RING2 acts as the main E3 ubiquitin ligase on histone H2A of the PRC1 complex, while RING1 may rather act as a modulator of RNF2/RING2 activity. Members of this family contain a C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4506561  130 VSCPICMDgyseIVQNGRliVSTECGHVFCSQCLRDSLKNANT-CPTCRKKINHKR 184
Cdd:cd16531   2 LMCPICLG----IIKNTM--TVKECLHRFCAECIEKALRLGNKeCPTCRKHLPSRR 51

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 4506561     132 CPICMDGYSEivqngrLIVSTECGHVFCSQCLRDSLKNAN-TCPTC 176
Cdd:smart00184   1 CPICLEEYLK------DPVILPCGHTFCRSCIRKWLESGNnTCPIC 40

RING finger, HC subclass, found in postreplication repair protein RAD18 and similar proteins; RAD18, also known as HR18 or RING finger protein 73 (RNF73), is an E3 ubiquitin-protein ligase involved in post replication repair of UV-damaged DNA via its recruitment to stalled replication forks. It associates to the E2 ubiquitin conjugating enzyme UBE2B to form the UBE2B-RAD18 ubiquitin ligase complex involved in mono-ubiquitination of DNA-associated PCNA on K164. It also interacts with another E2 ubiquitin conjugating enzyme RAD6 to form a complex that monoubiquitinates proliferating cell nuclear antigen at stalled replication forks in DNA translesion synthesis. Moreover, Rad18 is a key factor in double-strand break DNA damage response (DDR) pathways via its association with K63-linked polyubiquitylated chromatin proteins. It can function as a mediator for DNA damage response signals to activate the G2/M checkpoint in order to maintain genome integrity and cell survival after ionizing radiation (IR) exposure. RAD18 contains a C3HC4-type RING-HC finger, a ubiquitin-binding zinc finger domain (UBZ), a SAP (SAF-A/B, Acinus and PIAS) domain, and a RAD6-binding domain (R6BD).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 4506561  132 CPICMDGYSEIVqngrliVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHKR 184
Cdd:cd16529   7 CPICFEYFNTAM------MITQCSHNYCSLCIRRFLSYKTQCPTCRAAVTESD 53

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Deltex3 (DTX3), Deltex-3-like (DTX3L) and similar proteins; This subfamily contains Deltex3 (DTX3) and Deltex-3-like (DTX3L), both of which are E3 ubiquitin-protein ligases belonging to the Deltex (DTX) family. DTX3, also known as RING finger protein 154 (RNF154), has a biological function that remains unclear. DTX3L, also known as B-lymphoma- and BAL-associated protein (BBAP) or Rhysin-2 (Rhysin2), regulates endosomal sorting of the G protein-coupled receptor CXCR4 from endosomes to lysosomes. It also regulates subcellular localization of its partner protein, B aggressive lymphoma (BAL), by a dynamic nucleocytoplasmic trafficking mechanism. In contrast to other DTXs, both DTX3 and DTX3L contain a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain. DTX3L can associate with DTX1 through its unique N termini and further enhance self-ubiquitination.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 4506561  132 CPICMDgysEIVQNGRLivsTECGHVFCSQCLRDSLKNANTCPTCR 177
Cdd:cd16506   3 CPICLD---EIQNKKTL---EKCKHSFCEDCIDRALQVKPVCPVCG 42

RING finger, HC subclass, found in RING finger protein 220 (RNF220) and similar proteins; RNF220 is an E3 ubiquitin-protein ligase that promotes the ubiquitination and proteasomal degradation of Sin3B, a scaffold protein of the Sin3/HDAC (histone deacetylase) corepressor complex. It can also bind E2 and mediate auto-ubiquitination of itself. Moreover, RNF220 specifically interacts with beta-catenin, and enhances canonical Wnt signaling through ubiquitin-specific protease 7 (USP7)-mediated deubiquitination and stabilization of beta-catenin, which is independent of its E3 ligase activity. RNF220 contains a characteristic C3HC4-type RING-HC finger at its C-terminus.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 4506561  131 SCPICMDGYSEIVqngrliVSTECGHVFCSQCLRDSLKNANTCPTC 176
Cdd:cd16563   2 KCLICMDSYTMPL------VSIQCWHVHCEECWLRTLGAKKLCPQC 41

N1R/p28-like protein; Provisional

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 4506561   132 CPICMDG-YSEIVQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKK 179
Cdd:PHA02929 177 CAICMEKvYDKEIKNMYFGILSNCNHVFCIECIDIWKKEKNTCPVCRTP 225

RING finger, HC subclass, found in RING finger protein 170 (RNF170) and similar proteins; RNF170, also known as putative LAG1-interacting protein, is an endoplasmic reticulum (ER) membrane-bound E3 ubiquitin-protein ligase that mediates ubiquitination-dependent degradation of type-I inositol 1,4,5-trisphosphate (IP3) receptors (ITPR1) via the endoplasmic-reticulum-associated protein degradation (ERAD) pathway. A point mutation (arginine to cysteine at position 199) in the RNF170 gene is linked with autosomal-dominant sensory ataxia (ADSA), a disease characterized by neurodegeneration in the posterior columns of the spinal cord. RNF170 contains a C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4506561  131 SCPICMdgyseivQNGRLIVSTECGHVFCSQCLR-----DSLKNANTCPTCRKKIN 181
Cdd:cd16553   3 ECPICL-------QDARFPVETNCGHLFCGPCIItywrhGSWLGAVSCPVCRQTVT 51

RING finger, H2 subclass, found in the PA-TM-RING ubiquitin ligase family; The PA-TM-RING family represents a group of transmembrane-type E3 ubiquitin ligases, which has been characterized by an N-terminal transient signal peptide, a PA (protease-associated) domain, a TM (transmembrane) domain, as well as a C-terminal C3H2C3-type RING-H2 finger domain. It includes RNF13, RNF167, ZNRF4 (zinc and RING finger 4), GRAIL (gene related to anergy in lymphocytes)/RNF128, RNF130, RNF133, RNF148, RNF149 and RNF150 (which are more closely related), as well as RNF43 and ZNRF3, which have substantially longer C-terminal tail extensions compared with the others. PA-TM-RING proteins are expressed at low levels in all mammalian tissues and species, but they are not present in yeast. They play a common regulatory role in intracellular trafficking/sorting, suggesting that abrogation of their function may result in dysregulation of cellular signaling events in cancer.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 4506561  131 SCPICMDGYSEivqnGRLIVSTECGHVFCSQCLRDSLKNANTCPTCR 177
Cdd:cd16454   1 TCAICLEEFKE----GEKVRVLPCNHLFHKDCIDPWLEQHNTCPLCR 43

RING finger, HC subclass, found in tripartite motif-containing protein 40 (TRIM40) and similar proteins; TRIM40, also known as probable E3 NEDD8-protein ligase or RING finger protein 35 (RNF35), is highly expressed in the gastrointestinal tract including the stomach, small intestine, and large intestine. It enhances neddylation of inhibitor of nuclear factor kappaB kinase subunit gamma (IKKgamma), inhibits the activity of nuclear factor-kappaB (NF-kappaB)-mediated transcription, and thus prevents inflammation-associated carcinogenesis in the gastrointestinal tract. TRIM40 belongs 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, as well as an uncharacterized region positioned C-terminal to the RBCC domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4506561  132 CPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNAN-----TCPTCRK 178
Cdd:cd16583   8 CPICQEPLKEAV-------STDCGHLFCRMCLTQHAKKASasgvfSCPVCRK 52

RING finger, HC subclass, found in RING finger protein 180 (RNF180) and similar proteins; RNF180, also known as Rines, is a membrane-bound E3 ubiquitin-protein ligase well conserved among vertebrates. It is a critical regulator of the monoaminergic system, as well as emotional and social behavior. It interacts with brain monoamine oxidase A (MAO-A) and targets it for ubiquitination and degradation. It also functions as a novel tumor suppressor in gastric carcinogenesis. The hypermethylated CpG site count of the RNF180 DNA promoter can be used to predict survival of gastric cancer. RNF180 contains a novel conserved dual specificity protein phosphatase Rines conserved (DSPRC) domain, a basic coiled-coil domain, a C3HC4-type RING-HC finger, and a C-terminal hydrophobic region that is predicted to be a transmembrane domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 4506561  131 SCPICMDGYSeivqngRLIVSTECGHVFCSQCLRDSLKN--ANT-CPTCRKKINH 182
Cdd:cd16554   4 TCPVCLDLYY------DPYMCYPCGHIFCEPCLRQLAKSspKNTpCPLCRTTIRR 52

RING finger, HC subclass, found in RING finger protein 125 (RNF125); RNF125, also known as T-cell RING activation protein 1 (TRAC-1), is an E3 ubiquitin-protein ligase that is predominantly expressed in lymphoid cells, and functions as a positive regulator of T cell activation. It also down-modulates HIV replication and inhibits pathogen-induced cytokine production. It negatively regulates type I interferon signaling, which conjugates Lys(48)-linked ubiquitination to retinoic acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. Further, RNF125 conjugates ubiquitin to melanoma differentiation-associated gene 5 (MDA5), a family protein of RIG-I. It thus acts as a negative regulator of RIG-I signaling, and is a direct target of miR-15b in the context of Japanese encephalitis virus (JEV) infection. Moreover, RNF125 binds to and ubiquitinates JAK1, prompting its degradation and inhibition of receptor tyrosine kinase (RTK) expression. It also negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation. Mutations in RNF125 may lead to overgrowth syndromes (OGS). RNF125, together with three closely related proteins: RNF114, RNF138 and RNF166, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM). The UIM of RNF125 binds K48-linked poly-ubiquitin chains and is, together with the RING domain, required for auto-ubiquitination.

                        10        20        30
                ....*....|....*....|....*....|...
gi 4506561  150 VSTECGHVFCSQCLRDSLKNAN-TCPTCRKKIN 181
Cdd:cd16542  15 VRTRCGHVFCRPCIATSLRNNTwTCPYCRAYLS 47

RING finger, HC subclass, found in really interesting new gene 2 protein (RING2) and similar proteins; RING2, also known as huntingtin-interacting protein 2-interacting protein 3, HIP2-interacting protein 3, protein DinG, RING finger protein 1B (RING1B), RING finger protein 2 (RNF2), or RING finger protein BAP-1, is an E3 ubiquitin-protein ligase that interacts with both nucleosomal DNA and an acidic patch on histone H4 to achieve the specific monoubiquitination of K119 on histone H2A (H2AK119ub), thereby playing a central role in histone code and gene regulation. RING2 is a core component of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. The enzymatic activity of RING2 is enhanced by the interaction with BMI1/PCGF4, and it is dispensable for early embryonic development and much of the gene repression activity of PRC1. Moreover, RING2 plays a key role in terminating neural precursor cell (NPC)-mediated production of subcerebral projection neurons (SCPNs) during neocortical development. It also plays a critical role in nonhomologous end-joining (NHEJ)-mediated end-to-end chromosome fusions. Furthermore, RING2 is essential for expansion of hepatic stem/progenitor cells. It promotes hepatic stem/progenitor cell expansion through simultaneous suppression of cyclin-dependent kinase inhibitors (CDKIs) Cdkn1a and Cdkn2a, known negative regulators of cell proliferation. RING2 also negatively regulates p53 expression through directly binding with both p53 and MDM2 and promoting MDM2-mediated p53 ubiquitination in selective cancer cell types to stimulate tumor development. RING2 contains a C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 4506561  132 CPICMDgyseIVQNgrLIVSTECGHVFCSQCLRDSLKNANT-CPTCRKKINHKR 184
Cdd:cd16740  15 CPICLD----MLKN--TMTTKECLHRFCADCIITALRSGNKeCPTCRKKLVSKR 62

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.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 4506561  132 CPICMDGYseivqngRLIVSTECGHVFCSQCLRDSLKNAN-TCPTCR 177
Cdd:cd16509   6 CAICLDSL-------TNPVITPCAHVFCRRCICEVIQREKaKCPMCR 45

RING finger, HC subclass, found in breast cancer type 1 susceptibility protein (BRCA1) and similar proteins; BRCA1, also known as RING finger protein 53 (RNF53), is a RING finger protein encoded by the tumor suppressor gene BRCA1 that regulates all DNA double-strand break (DSB) repair pathways. BRCA1 is frequently mutated in patients with hereditary breast and ovarian cancer (HBOC). Its mutation is also associated with an increased risk of pancreatic, stomach, laryngeal, fallopian tube, and prostate cancer. It plays an important role in the DNA damage response signaling and has been implicated in various cellular processes such as cell cycle regulation, transcriptional regulation, chromatin remodeling, DNA DSBs, and apoptosis. BRCA1 contains an N-terminal C3HC4-type RING-HC finger, and two BRCT (BRCA1 C-terminus domain) repeats at the C-terminus.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 4506561  129 TVSCPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNANT---CPTCRKKINhKR 184
Cdd:cd16498  16 NLECPICLELLKEPV-------STKCDHQFCRFCILKLLQKKKKpapCPLCKKSVT-KR 66

RING finger, HC subclass, found in Arabidopsis thaliana protein BREAST CANCER SUSCEPTIBILITY 1 homolog (AtBRCA1) and similar proteins; AtBRCA1 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). AtBRCA1 contains a typical C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 4506561  130 VSCPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNANTCPTCrKKINHKR 184
Cdd:cd23147   5 LKCPICLSLFKSAA-------NLSCNHCFCAGCIGESLKLSAICPVC-KIPATRR 51

H2 subclass of RING (RING-H2) fingers and its variants; 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). This family corresponds to the H2 subclass of RING (RING-H2) finger proteins that are characterized by containing C3H2C3-type canonical RING-H2 fingers or noncanonical RING-H2 finger variants, including C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type modified RING-H2 fingers. The canonical RING-H2 finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-H-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-H2 finger can be found in 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 serves as a scaffold for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 4506561  132 CPICMDGYSEivqnGRLIVSTECGHVFCSQCLRDSLKNAN-TCPTCR 177
Cdd:cd16448   1 CVICLEEFEE----GDVVRLLPCGHVFHLACILRWLESGNnTCPLCR 43

RING-finger-containing E3 ubiquitin ligase [Posttranslational modification, protein turnover, chaperones];

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 4506561  112 TPRNARDEGATGLRPSGTVSCPICMDgyseivqNGRLIVSTECGHVFCSQCLRDSLKNANT--CPTCRKK 179
Cdd:COG5574 198 TKENLSKKNGLPFIPLADYKCFLCLE-------EPEVPSCTPCGHLFCLSCLLISWTKKKYefCPLCRAK 260

Modified RING finger, HC subclass (C3HC3D-type), found in PHD and RING finger domain-containing protein 1 (PHRF1) and similar proteins; PHRF1, also known as KIAA1542, or CTD-binding SR-like protein rA9, is a ubiquitin ligase which induces the ubiquitination of TGIF (TG-interacting factor) at lysine 130. It acts as a tumor suppressor that promotes the transforming growth factor (TGF)-beta cytostatic program through selective release of TGIF-driven promyelocytic leukemia protein (PML) inactivation. PHRF1 contains a plant homeodomain (PHD) finger and a modified C3HC3D-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4506561  131 SCPICMDGYSEivqngrLIVST--ECGHVFCSQCLRDSLKNANTCPTCRKK 179
Cdd:cd16635   6 SCPICLNTFRD------QAVGTpeSCDHIFCLDCILEWSKNANTCPVDRIV 50

RING finger, HC subclass, found in protein Deltex-3-like (DTX3L) and similar proteins; DTX3L, also known as B-lymphoma- and BAL-associated protein (BBAP) or Rhysin-2 (Rhysin2), is a RING-domain E3 ubiquitin-protein ligase that regulates endosomal sorting of the G protein-coupled receptor CXCR4 from endosomes to lysosomes. It also regulates subcellular localization of its partner protein, B aggressive lymphoma (BAL), by a dynamic nucleocytoplasmic trafficking mechanism. DTX3L has a unique N-terminus, but lacks the highly basic N-terminal motif and the central proline-rich motif present in other Deltex (DTX) family members, such as DTX1, DTX2, and DTX4. Moreover, its C-terminal region is highly homologous to DTX3. It includes a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain. DTX3L can associate with DTX1 through its unique N-terminus and further enhance self-ubiquitination.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 4506561  132 CPICMDgysEIVQNGRLivsTECGHVFCSQCLRDSLKNANTCPTC 176
Cdd:cd16712   6 CPICMD---RISNKKVL---PKCKHVFCAACIDKAMKYKPVCPVC 44

RING finger, HC subclass, found in tripartite motif-containing proteins, TRIM7, TRIM11 and TRIM27, and similar proteins; TRIM7, TRIM11 and TRIM27, closely related tripartite motif-containing proteins, belong 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, Bbox2, and a coiled coil region, as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain. TRIM7, also known as glycogenin-interacting protein (GNIP) or RING finger protein 90 (RNF90), is an E3 ubiquitin-protein ligase that mediates c-Jun/AP-1 activation by Ras signalling. Its phosphorylation and activation by MSK1 in response to direct activation by the Ras-Raf-MEK-ERK pathway can stimulate TRIM7 E3 ubiquitin ligase activity in mediating Lys63-linked ubiquitination of the AP-1 coactivator RACO-1, leading to RACO-1 protein stabilization. Moreover, TRIM7 binds and activates glycogenin, the self-glucosylating initiator of glycogen biosynthesis. TRIM11, also known as protein BIA1, or RING finger protein 92 (RNF92), is an E3 ubiquitin-protein ligase involved in the development of the central nervous system. It is overexpressed in high-grade gliomas and promotes proliferation, invasion, migration and glial tumor growth. TRIM11 acts as a potential therapeutic target for congenital central hypoventilation syndrome (CCHS) by mediating the degradation of CCHS-associated polyalanine-expanded Phox2b. TRIM11 modulates the function of neurogenic transcription factor Pax6 through the ubiquitin-proteosome system, and thus plays an essential role for Pax6-dependent neurogenesis. It also binds to and destabilizes a key component of the activator-mediated cofactor complex (ARC105), humanin, a neuroprotective peptide against Alzheimer's disease-relevant insults, and further regulates ARC105 function in transforming growth factor beta (TGFbeta) signaling. Moreover, TRIM11 negatively regulates retinoic acid-inducible gene-I (RIG-I)-mediated interferon-beta (IFNbeta) production and antiviral activity by targeting TANK-binding kinase-1 (TBK1). It may contribute to the endogenous restriction of retroviruses in cells. It enhances N-tropic murine leukemia virus (N-MLV) entry by interfering with Ref1 restriction. It also suppresses the early steps of human immunodeficiency virus HIV-1 transduction, resulting in decreased reverse transcripts. TRIM27, also known as RING finger protein 76 (RNF76), RET finger protein (RFP), or zinc finger protein RFP, is a nuclear E3 ubiquitin-protein ligase that is highly expressed in testis and in various tumor cell lines. Expression of TRIM27 is associated with prognosis of colon and endometrial cancers. TRIM27 was first identified as a fusion partner of the RET receptor tyrosine kinase. It functions as a transcriptional repressor and associates with several proteins involved in transcriptional activity, such as enhancer of polycomb 1 (Epc1), a member of the Polycomb group proteins, and Mi-2beta, a main component of the nucleosome remodeling and deacetylase (NuRD) complex, and the cell cycle regulator retinoblastoma protein (RB1). It also interacts with HDAC1, leading to downregulation of thioredoxin binding protein 2 (TBP-2), which inhibits the function of thioredoxin. Moreover, TRIM27 mediates Pax7-induced ubiquitination of MyoD in skeletal muscle atrophy. In addition, it inhibits muscle differentiation by modulating serum response factor (SRF) and Epc1. TRIM27 promotes a non-canonical polyubiquitination of PTEN, a lipid phosphatase that catalyzes PtdIns(3,4,5)P3 (PIP3) to PtdIns(4,5)P2 (PIP2). It is an IKKepsilon-interacting protein that regulates IkappaB kinase (IKK) function and negatively regulates signaling involved in the antiviral response and inflammation. TRIM27 also forms a protein complex with MBD4 or MBD2 or MBD3, and thus plays an important role in the enhancement of transcriptional repression through MBD proteins in tumorigenesis, spermatogenesis, and embryogenesis. It is a component of an estrogen receptor 1 (ESR1) regulatory complex that is involved in estrogen receptor-mediated transcription in MCF-7 cells.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4506561  130 VSCPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNANT---CPTCRK 178
Cdd:cd16594   6 LTCPICLDYFTDPV-------TLDCGHSFCRACIARCWEEPETsasCPQCRE 50

RING finger, H2 subclass, found in DAZ (deleted in azoospermia)-interacting protein 3 (DZIP3) and similar proteins; DZIP3, also known as RNA-binding ubiquitin ligase of 138 kDa (RUL138) or 2A-HUB protein, is an RNA-binding E3 ubiquitin-protein ligase that interacts with coactivator-associated arginine methyltransferase 1 (CARM1) and acts as a transcriptional coactivator of estrogen receptor (ER) alpha. It is also a histone H2A ubiquitin ligase that catalyzes monoubiquitination of H2A at lysine 119, functioning as a combinatorial component of the repression machinery required for repressing a specific chemokine gene expression program, critically modulating migratory responses to Toll-like receptors (TLR) activation. DZIP3 contains a C3H2C3-type RING-H2 finger at the C-terminus.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 4506561  132 CPICMDGYseivQNGRLIVSTECGHVFCSQCLRDSLKNANTCPTCR 177
Cdd:cd16460   3 CVICHEAF----SDGDRLLVLPCAHKFHTQCIGPWLDGQQTCPTCR 44

RING finger, HC subclass, found in RING finger protein 168 (RNF168) and similar proteins; RNF168 is an E3 ubiquitin-protein ligase that promotes noncanonical K27 ubiquitination to signal DNA damage. It, together with RNF8, functions as a DNA damage response (DDR) factor that promotes a series of ubiquitylation events on substrates, such as H2A and H2AX with H2AK13/15 ubiquitylation, facilitates recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of double-strand breaks (DSBs), and inhibits homologous recombination (HR) in cells deficient in the tumor suppressor BRCA1. RNF168 also promotes H2A neddylation, which antagonizes ubiquitylation of H2A and regulates DNA damage repair. Moreover, RNF168 forms a functional complex with RAD6A or RAD6B during the DNA damage response. RNF168 contains an N-terminal C3HC4-type RING-HC finger that catalyzes H2A-K15ub and interacts with H2A, and two MIU (motif interacting with ubiquitin) domains responsible for the interaction with K63 linked poly-ubiquitin.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4506561  130 VSCPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNAN-TCPTCRKKI 180
Cdd:cd16550   1 CLCPICLEILVEPV-------TLPCNHTLCMPCFQSTVEKASlCCPLCRLRI 45

RING finger, H2 subclass, found in Arabidopsis thaliana protein ABA INSENSITIVE RING PROTEIN 1 (AIRP1) and similar proteins; This subfamily includes Arabidopsis thaliana AIRP1 and RING-H2 finger B1a (RHB1A). AIRP1, also known as RING-type E3 ubiquitin transferase AIRP1, possesses E3 ubiquitin-protein ligase activity in vitro when associated with the E2 enzyme UBC8. It plays combinatory roles with AIRP2 in the positive regulation of the abscisic acid-mediated drought stress response. RHB1A is a probable E3 ubiquitin-protein ligase. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 4506561  132 CPICMDGYSEivQNGRLIvsTECGHVFCSQCLRDSLKNANTCPTCRKKI 180
Cdd:cd23116   5 CPTCLEGYTE--ENPKLL--TKCGHHFHLACIYEWMERSERCPVCDKEM 49

RING finger, HC subclass, found in topoisomerase I-binding arginine/serine-rich protein (Topors) and similar proteins; Topors, also known as topoisomerase I-binding RING finger protein, tumor suppressor p53- binding protein 3, or p53-binding protein 3 (p53BP3), is a ubiquitously expressed nuclear E3 ubiquitin-protein ligase that can ligate both ubiquitin and small ubiquitin-like modifier (SUMO) to substrate proteins in the nucleus. It contains an N-terminal C3HC4-type RING-HC finger which ligates ubiquitin to its target proteins including DNA topoisomerase I, p53, NKX3.1, H2AX, and the AAV-2 Rep78/68 proteins. As a RING-dependent E3 ubiquitin ligase, Topors works with the E2 enzymes UbcH5a, UbcH5c, and UbcH6, but not with UbcH7, CDC34, or UbcH2b. Topors acts as a tumor suppressor in various malignancies. It regulates p53 modification, suggesting it may be responsible for astrocyte elevated gene-1 (AEG-1, also known as metadherin, or LYRIC) ubiquitin modification. Plk1-mediated phosphorylation of Topors inhibits Topors-mediated sumoylation of p53, whereas p53 ubiquitination is enhanced, leading to p53 degradation. It also functions as a negative regulator of the prostate tumor suppressor NKX3.1. Moreover, Topors is associated with promyelocytic leukemia nuclear bodies, and may be involved in the cellular response to camptothecin. It also plays a key role in the turnover of H2AX protein, discriminating the type of DNA damaging stress. Furthermore, Topors is a cilia-centrosomal protein associated with autosomal dominant retinal degeneration. Mutations in TOPORS cause autosomal dominant retinitis pigmentosa (adRP).

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 4506561  131 SCPICMDGYseivQNGRLIVSTeCGHVFCSQCLRDSLKNANTCPTCRKKI 180
Cdd:cd16574   3 SCPICLDRF----ENEKAFLDG-CFHAFCFTCILEWSKVKNECPLCKQPF 47

RING finger, HC subclass, found in RING finger protein 219 (RNF219) and similar proteins; RNF219 may function as a modulator of late-onset Alzheimer's disease (LOAD) associated amyloid beta A4 precursor protein (APP) endocytosis and metabolism. It genetically interacts with apolipoprotein E epsilon4 allele (APOE4). Thus, a genetic variant of RNF219 was found to affect amyloid deposition in human brain and LOAD age-of-onset. Moreover, common genetic variants at the RNF219 locus had been associated with alternations in lipid metabolism, cognitive performance and central nervous system ventricle volume. RNF219 contains a C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4506561  130 VSCPICMDGYSEIVqngrlIVSTEcgHVFCSQCLRDSLKNANTCPTCRKKI 180
Cdd:cd16562   2 ISCHICLGKVRQPV-----ICSNN--HVFCSSCMDVWLKNNNQCPACRVPI 45

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 4506561    132 CPICMDgyseivqNGRLIVSTECGH-VFCSQCLRDSLKNANTCPTCRKKI 180
Cdd:pfam13920   5 CVICLD-------RPRNVVLLPCGHlCLCEECAERLLRKKKKCPICRQPI 47

RING finger, HC subclass, found in tripartite motif-containing protein 69 (TRIM69) and similar proteins; TRIM69, also known as RFP-like domain-containing protein trimless or RING finger protein 36 (RNF36), is a testis E3 ubiquitin-protein ligase that plays a specific role in apoptosis and may also play an important role in germ cell homeostasis during spermatogenesis. TRIM69 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        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4506561  131 SCPICMDGYseivqngRLIVSTECGHVFCSQCLR---DSLKNANTCPTCRK 178
Cdd:cd16611   6 HCPLCLDFF-------RDPVMLSCGHNFCQSCITgfwELQAEDTTCPECRE 49

RING finger, HC subclass, found in peroxin-10 (PEX10) and similar proteins; PEX10, also known as peroxisome biogenesis factor 10, peroxisomal biogenesis factor 10, peroxisome assembly protein 10, or RING finger protein 69 (RNF69), is an integral peroxisomal membrane protein with two transmembrane regions and a C3HC4-type RING-HC finger within its cytoplasmically exposed C-terminus. It plays an essential role in peroxisome assembly, import of target substrates, and recycling or degradation of protein complexes and amino acids. It is an essential component of the spinal locomotor circuit, and thus its mutations may be involved in peroxisomal biogenesis disorders (PBD). Mutations in human PEX10 also result in autosomal recessive ataxia. Moreover, PEX10 functions as an E3-ubiquitin ligase with an E2, UBCH5C. It mono- or poly-ubiquitinates PEX5, a key player in peroxisomal matrix protein import, in a UBC4-dependent manner, to control PEX5 receptor recycling or degradation. It also links the E2 ubiquitin conjugating enzyme PEX4 to the protein import machinery of the peroxisome.

                        10        20        30
                ....*....|....*....|....*....|....
gi 4506561  151 STECGHVFCSQCLRDSLKNANTCPTCRKKINHKR 184
Cdd:cd16527  15 ATPCGHLFCWSCITEWCNEKPECPLCREPFQPQR 48

RING finger, HC subclass, found in Equid alphaherpesvirus 1 (Equine herpesvirus 1/EHV-1) regulatory protein and similar proteins; EHV-1 regulatory protein belongs to the Vmw110 (IPC0) protein family. It contains a typical C3HC4-type RING-HC finger and binds zinc stably.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4506561  131 SCPICMDGYSEivqngrLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHKRYH 186
Cdd:cd23130   2 VCPICLDDPED------EAITLPCLHQFCYTCILRWLQTSPTCPLCKTPVTSIIHS 51

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM41, TRIM52 and similar proteins; TRIM41 and TRIM52, two closely related tripartite motif-containing proteins, have dramatically expanded RING domains compared with the rest of the TRIM family proteins. TRIM41 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. In contrast, TRIM52 lacks the putative viral recognition SPRY/B30.2 domain, and thus has been classified to the C-V subclass of the TRIM family that contains only RBCC domains. TRIM41, also known as RING finger-interacting protein with C kinase (RINCK), is an E3 ubiquitin-protein ligase that promotes the ubiquitination of protein kinase C (PKC) isozymes in cells. It specifically recognizes the C1 domain of PKC isozymes. It controls the amplitude of PKC signaling by controlling the amount of PKC in the cell. TRIM52, also known as RING finger protein 102 (RNF102), is encoded by a novel, noncanonical antiviral TRIM52 gene in primate genomes with unique specificity determined by the rapidly evolving RING domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4506561  132 CPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLknANTCPTCRKKINHKRYHP 187
Cdd:cd16602   6 CAICLDYFKDPV-------SIGCGHNFCRVCVTQLW--GFTCPQCRKSFPRRSFRP 52

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.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 4506561  130 VSCPICMDGYSEIVqngrlivSTECGHVFCSQCLR---DSLKN-ANTCPTCRK 178
Cdd:cd16597   6 LTCSICLELFKDPV-------TLPCGHNFCGVCIEktwDSQHGsEYSCPQCRA 51

RING finger, H2 subclass, found in RING finger protein 115 (RNF115) and similar proteins; RNF115, also known as Rab7-interacting ring finger protein (Rabring 7), or zinc finger protein 364 (ZNF364), or breast cancer-associated gene 2 (BCA2), is an E3 ubiquitin-protein ligase that is an endogenous inhibitor of adenosine monophosphate-activated protein kinase (AMPK) activation and its inhibition increases the efficacy of metformin in breast cancer cells. It also functions as a co-factor in the restriction imposed by tetherin on HIV-1, and targets HIV-1 Gag for lysosomal degradation, impairing virus assembly and release, in a tetherin-independent manner. Moreover, RNF115 is a Rab7-binding protein that stimulates c-Myc degradation through mono-ubiquitination of MM-1. It also plays crucial roles as a Rab7 target protein in vesicle traffic to late endosome/lysosome and lysosome biogenesis. Furthermore, RNF115 and the related protein, RNF126 associate with the epidermal growth factor receptor (EGFR) and promote ubiquitylation of EGFR, suggesting they play a role in the ubiquitin-dependent sorting and downregulation of membrane receptors. RNF115 contains an N-terminal BCA2 Zinc-finger domain (BZF), the AKT-phosphorylation sites, and the C-terminal C3H2C3-type RING-H2 finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4506561  130 VSCPICMDGYSEivqnGRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKIN 181
Cdd:cd16800   1 LECPVCKEDYTV----GEQVRQLPCNHFFHSDCIVPWLELHDTCPVCRKSLN 48

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.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 4506561  132 CPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNAN----TCPTCRKKINHK 183
Cdd:cd16609   6 CSICLGLYQDPV-------TLPCQHSFCRACIEDHWRQKDegsfSCPECRAPFPEG 54

RING finger, H2 subclass, found in Arabidopsis thaliana MED25-binding RING-H2 protein (MBR) and similar proteins; This subfamily includes MBR1 and MBR2 (also called HAL3-interacting protein 1 or AtHIP1). They are E3 ubiquitin-protein ligases that function as regulators of MED25 stability by targeting MED25 for degradation in a RING-H2-dependent manner. Proteasome-dependent degradation of MED25 seems to activate its function as a positive regulator of FLOWERING LOCUS T (FT) and is important to induce the expression of FT, and consequently to promote flowering. MBR2 may also function downstream of HAL3 and be required for HAL3-regulated plant growth. Activation of MBR2 by HAL3 may lead to the degradation of cell cycle suppressors, resulting in enhancement of cell division and plant growth. Both MBR1 and MBR2 contain a C3H2C3-type RING-H2 finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 4506561  130 VSCPICMDGYSEIVQNGRLivstECGHVFCSQCLRDSLKNANTCPTCR 177
Cdd:cd23113   3 EKCCICQEEYEEGDELGTI----ECGHEYHSDCIKQWLVQKNLCPICK 46

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.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 4506561  131 SCPICmdgySEIVQNGRLIvsTECGHVFCSQCLRDSLKNAN-TCPTCRKKI 180
Cdd:cd16620   5 KCPIC----KDLMKDAVLT--PCCGNSFCDECIRTALLEEDfTCPTCKEPD 49

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.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 4506561  132 CPICMDGYseivqngRLIVSTECGHVFCSQCLRDSLKNANTCPTCRKKINHK 183
Cdd:cd23146   7 CPICLKLL-------NRPVLLPCDHIFCSSCITDSTKVGSDCPVCKLPYHSQ 51

Modified RING finger, HC subclass (C3HC3D-type), found in ligand of Numb protein LNX1, LNX2, and similar proteins; The ligand of Numb protein X (LNX) family, also known as PDZ and RING (PDZRN) family, includes LNX1-5, which can interact with Numb, a key regulator of neurogenesis and neuronal differentiation. LNX5 (also known as PDZK4 or PDZRN4L) shows high sequence homology to LNX3 and LNX4, but it lacks the RING domain. LNX1-4 proteins function as E3 ubiquitin ligases and have a unique domain architecture consisting of an N-terminal RING-HC finger for E3 ubiquitin ligase activity and either two or four PDZ domains necessary for substrate-binding. LNX1/LNX2-like proteins contain a modified C3HC3D-type RING-HC finger and four PDZ domains. This model corresponds to the RING finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|...
gi 4506561  132 CPICMDGYSEIVQngrlivsTECGHVFCSQCLRDSLKNANTCP 174
Cdd:cd16637   4 CHICLQPLVEPLD-------TPCGHTFCYKCLTNYLKIQQCCP 39

RING finger, HC subclass, found in Mus musculus tripartite motif-containing protein 43 (TRIM43) and similar propteins; This subfamily includes TRIM43A, TRIM43B and TRIM43C, which are expressed specifically in mouse preimplantation embryos. They contain a typical C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 4506561  129 TVSCPICMdgysEIVQNGrliVSTECGHVFCSQCL---RDSLKNANTCPTCRKKINHK 183
Cdd:cd23133   3 TLTCSICQ----GIFMNP---VYLRCGHKFCEACLllfQEDIKFPAYCPMCRQPFNQE 53

RING finger, HC subclass, found in Arabidopsis thaliana proteolysis 1 protein (PRT1) and similar proteins; PRT1, also called RING-type E3 ubiquitin transferase PRT1, is an E3 ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins. It functions in the N-end rule pathway of protein degradation, where it specifically recognizes and ubiquitinates proteins with an N-terminal bulky aromatic amino acid (Phe). It does not act on aliphatic hydrophobic and basic N-terminal residues (Arg or Leu) containing proteins. PRT1 contains a typical C3HC4-type RING-HC finger.

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                ....*....|....*....|....*....|....*....|....*....|...
gi 4506561  132 CPICMDgyseIVQNGrliVSTECGHVFCSQCLRDSLKN--ANTCPTCRKKINH 182
Cdd:cd23132   5 CCICLD----LLYKP---VVLECGHVFCFWCVHRCMNGydESHCPLCRRPYDH 50

RING finger, HC subclass, found in RING finger proteins RNF113A, RNF113B, and similar proteins; RNF113A, also known as zinc finger protein 183 (ZNF183), is an E3 ubiquitin-protein ligase that physically interacts with the E2 protein, UBE2U. A nonsense mutation in RNF113A is associated with an X-linked trichothiodystrophy (TTD). Its yeast ortholog Cwc24p is predicted to have a spliceosome function and acts in a complex with Cef1p to participate in pre-U3 snoRNA splicing, indirectly affecting pre-rRNA processing. It is also important for the U2 snRNP binding to primary transcripts and co-migrates with spliceosomes. Moreover, the ortholog of RNF113A in fruit flies may also act as a spliceosome and is hypothesized to be involved in splicing, namely within the central nervous system. The ortholog in Caenorhabditis elegans is involved in DNA repair of inter-strand crosslinks. RNF113B, also known as zinc finger protein 183-like 1, shows high sequence similarity with RNF113A. Both RNF113A and RNF113B contain a CCCH-type zinc finger, which is commonly found in RNA-binding proteins involved in splicing, and a C3HC4-type RING-HC finger, which is frequently found in E3 ubiquitin ligases.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 4506561  132 CPICMDGYSEIVQngrlivsTECGHVFCSQCLRDSLKNANTCPTCRKKIN 181
Cdd:cd16539   8 CFICRKPFKNPVV-------TKCGHYFCEKCALKHYRKSKKCFVCGKQTN 50

RING finger, HC subclass, found in tripartite motif-containing protein TRIM4 and similar proteins; TRIM4 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, Bbox2, and a coiled coil region, as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain. TRIM4, also known as RING finger protein 87 (RNF87), is a cytoplasmic E3 ubiquitin-protein ligase that has recently evolved and is present only in higher mammals. It transiently interacts with mitochondria, induces mitochondrial aggregation and sensitizes the cells to hydrogen peroxide (H2O2) induced death. Its interaction with peroxiredoxin 1 (PRX1) is critical for the regulation of H2O2 induced cell death. Moreover, TRIM4 functions as a positive regulator of RIG-I-mediated type I interferon induction. It regulates the K63-linked ubiquitination of RIG-1 and assembly of antiviral signaling complex at the mitochondria.

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                ....*....|....*....|....*....|....*....|....*....|.
gi 4506561  130 VSCPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKNAN---TCPTCR 177
Cdd:cd16590   7 LTCPICLDYFQDPV-------SIECGHNFCRGCLHRNWAPGGgpfPCPECR 50

RING finger, H2 subclass, found in RING finger protein 11 (RNF11) and similar proteins; RNF11 is an E3 ubiquitin-protein ligase that acts both as an adaptor and a modulator of itch-mediated control of ubiquitination events underlying membrane traffic. It acts downstream of an enzymatic cascade for the ubiquitination of specific substrates. It is also a molecular adaptor of homologous to E6-associated protein C-terminus (HECT)-type ligases. RNF11 has been implicated in the regulation of several signaling pathways. It enhances transforming growth factor receptor (TGFR) signaling by both abrogating Smurf2-mediated receptor ubiquitination and by promoting the Smurf2-mediated degradation of AMSH (associated molecule with the SH3 domain of STAM), a de-ubiquitinating enzyme that enhances TGF-beta signaling and epidermal growth factor receptor (EGFR) endosomal recycling. It also acts directly on Smad4 to enhance Smad4 function, and plays a role in prolonged TGF-beta signaling. RNF11 also functions as a critical component of the A20 ubiquitin-editing protein complex that negatively regulates tumor necrosis factor (TNF)-mediated nuclear factor (NF)-kappaB activation. It interacts with Smad anchor for receptor activation (SARA) and the endosomal sorting complex required for transport (ESCRT)-0 complex, thus participating in the regulation of lysosomal degradation of EGFR. RNF11 acts as a novel GGA cargo actively participating in regulating the ubiquitination of the GGA protein family. RNF11 functions together with TAX1BP1 to target TANK-binding kinase 1 (TBK1)/IkappaB kinase IKKi, and further restricts antiviral signaling and type I interferon (IFN)-beta production. RNF11 contains an N-terminal PPPY motif that binds WW domain-containing proteins such as AIP4/itch, Nedd4 and Smurf1/2 (SMAD-specific E3 ubiquitin-protein ligase 1/2), and a C-terminal C3H2C3-type RING-H2 finger that functions as a scaffold for the coordinated transfer of ubiquitin to substrate proteins together with the E2 enzymes UbcH527 and Ubc13.

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                ....*....|....*....|....*....|....*....|....*
gi 4506561  132 CPICMDGYSEivqnGRLIVSTECGHVFCSQCLRDSLKNANTCPTC 176
Cdd:cd16468   2 CVICMADFVV----GDPIRYLPCMHIYHVDCIDDWLMRSFTCPSC 42

RING finger found in polycomb group RING finger protein 3 (PCGF3) and similar proteins; PCGF3, also known as RING finger protein 3A (RNF3A), is one of six PcG RING finger (PCGF) homologs (PCGF1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF3 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. PCGF3 contains a C3HC4-type RING-HC finger.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 4506561  152 TECGHVFCSQCLRDSLKNANTCPTCRKKINHKryHPI 188
Cdd:cd16735  28 TECLHTFCKSCLVKYLEENNTCPTCGIVIHQS--HPL 62

RING finger, HC subclass, found in ubiquitin-like PHD and RING finger domain-containing proteins, UHRF1 and UHRF2, and similar proteins; UHRF1 is a unique chromatin effector protein that integrates the recognition of both histone PTMs and DNA methylation. It is essential for cell proliferation and plays a critical role in the development and progression of many human carcinomas, such as laryngeal squamous cell carcinoma (LSCC), gastric cancer (GC), esophageal squamous cell carcinoma (ESCC), colorectal cancer, prostate cancer, and breast cancer. UHRF1 acts as a transcriptional repressor through its binding to histone H3 when it is unmodified at Arg2. Its overexpression in human lung fibroblasts results in downregulation of expression of the tumor suppressor pRB. It also plays a role in transcriptional repression of the cell cycle regulator p21. Moreover, UHRF1-dependent repression of transcription factors can facilitate the G1-S transition. It interacts with Tat-interacting protein of 60 kDa (TIP60) and induces degradation-independent ubiquitination of TIP60. It is also an N-methylpurine DNA glycosylase (MPG)-interacting protein that binds MPG in a p53 status-independent manner in the DNA base excision repair (BER) pathway. In addition, UHRF1 functions as an epigenetic regulator that is important for multiple aspects of epigenetic regulation, including maintenance of DNA methylation patterns and recognition of various histone modifications. 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) by interacting with the HBV core protein and promoting its degradation. Both UHRF1 and UHRF2 contain an N-terminal ubiquitin-like domain (UBL), a tandem Tudor domain (TTD), a plant homeodomain (PHD) finger, a SET- and RING-associated (SRA) domain, and a C-terminal C3HC4-type RING-HC finger.

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gi 4506561  150 VSTECGHVFCSQCLRDSLK-NANTCPTCR 177
Cdd:cd16613  14 ITTPCKHNICKSCLQRSFKaEVYTCPACR 42

RING finger, HC subclass, found in Arabidopsis thaliana protein CHROMATIN REMODELING 27 (CHR27) and similar proteins; CHR27, also called protein SNF2-RING-HELICASE-LIKE 1, is a probable helicase-like transcription factor involved in transcriptional gene silencing. It associates with SUVR2 and contributes to transcriptional gene silencing at RNA-directed DNA methylation (RdDM) target loci but also at RdDM-independent target loci. It may be involved in nucleosome positioning to form ordered nucleosome arrays on chromatin. It associates with SUVR2 and functions redundantly with FRG2. It is required for the efficient methylation of a broad range of RdDM target loci. CHR27 contains a typical C3HC4-type RING-HC finger.

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                ....*....|....*....|....*....|....*....|....*....|....*
gi 4506561  132 CPICMDGYSEIVqngrlivSTECGHVFCSQCLRDSLKN------ANTCPTCRKKI 180
Cdd:cd23142   3 CPICNDPPEDAV-------VTLCGHVFCCECVFQYLSSdrtcrqFNHCPLCRQKL 50