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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1799133748  26 CTICLSTRFSQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCR 68
Cdd:cd16574     4 CPICLDRFENEKAFLDGCFHAFCFTCILEWS--KVKNECPLCK 44

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
                  ....*....|....*....|....*....|....*....|...
gi 1799133748  26 CTICLSTRFSQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCR 68
Cdd:cd16574     4 CPICLDRFENEKAFLDGCFHAFCFTCILEWS--KVKNECPLCK 44

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1799133748  25 QCTICLST-RFSQECRIEGCNHSFCFSCISEWVCQSlrPSCPMCR 68
Cdd:pfam13639   2 ECPICLEEfEEGDKVVVLPCGHHFHRECLDKWLRSS--NTCPLCR 44

RING-finger-containing E3 ubiquitin ligase [Signal transduction mechanisms];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1799133748  24 LQCTIClSTRFSQECrIEGCNHSFCFSCISEWVCQslRPSCPMCRkdvdkvsYDFSEQKLgQKEIAIKEYRSGHMSLTPT 103
Cdd:COG5432    26 LRCRIC-DCRISIPC-ETTCGHTFCSLCIRRHLGT--QPFCPVCR-------EDPCESRL-RGSSGSREINESHARNRDL 93

                          90
                  ....*....|.
gi 1799133748 104 DRVQLLSERRL 114
Cdd:COG5432    94 LRKVLESLCRL 104

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1799133748  20 PVEE-LQCTIClsTRFSQECRIEGCNHSFCFSCISEwvCQSLRPSCPMCRkdvdkvsYDFSEQKLgQKEIAIKEYRSGHM 98
Cdd:TIGR00599  22 PLDTsLRCHIC--KDFFDVPVLTSCSHTFCSLCIRR--CLSNQPKCPLCR-------AEDQESKL-RSNWLVSEIVESFK 89

                  ....*
gi 1799133748  99 SLTPT 103
Cdd:TIGR00599  90 NLRPS 94

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
                  ....*....|....*....|....*....|....*....|...
gi 1799133748  26 CTICLSTRFSQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCR 68
Cdd:cd16574     4 CPICLDRFENEKAFLDGCFHAFCFTCILEWS--KVKNECPLCK 44

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 1799133748   26 CTICLStRFSQECRIEGCNHSFCFSCISEWVcQSLRPSCPMC 67
Cdd:smart00184   1 CPICLE-EYLKDPVILPCGHTFCRSCIRKWL-ESGNNTCPIC 40

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 1799133748  26 CTICLSTrFSQECRIEGCNHSFCFSCISEWVcQSLRPSCPMC 67
Cdd:pfam00097   1 CPICLEE-PKDPVTLLPCGHLFCSKCIRSWL-ESGNVTCPLC 40

RING finger, HC subclass, found in checkpoint with forkhead and RING finger domains protein (CHFR); CHFR, also known as RING finger protein 196 (RNF196), is a checkpoint protein that delays entry into mitosis in response to stress. It functions as an E3 ubiquitin ligase that ubiquitinates and degrades its target proteins, such as Aurora-A, Plk1, Kif22, and PARP-1, which are critical for proper mitotic transitions. It also plays an important role in cell cycle progression and tumor suppression, and is negatively regulated by SUMOylation-mediated proteasomal ubiquitylation. Moreover, CHFR is involved in the early stage of the DNA damage response, which mediates the crosstalk between ubiquitination and poly-ADP-ribosylation. CHFR contains a fork head associated (FHA) domain and a C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1799133748  22 EELQCTICLSTRFSQECRIEgCNHSFCFSCISEWVCQSLrPSCPMCRKDVDKVS 75
Cdd:cd16503     1 ENLTCSICQDLLHDCVSLQP-CMHNFCAACYSDWMERSN-TECPTCRATVQRVN 52

RING finger, HC subclass, found in RING finger protein 8 (RNF8) and similar proteins; RNF8 is a telomere-associated E3 ubiquitin-protein ligase that plays an important role in DNA double-strand break (DSB) repair via histone ubiquitination. It is localized in the nucleus and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3), but not with other E2s (UbcH5, UbcH7, UbcH10, hCdc34, and hBendless). It recruits UBC13 for lysine 63-based self polyubiquitylation. Its deficiency causes neuronal pathology and cognitive decline, and its loss results in neuron degeneration. RNF8, together with RNF168, catalyzes a series of ubiquitylation events on substrates such as H2A and H2AX, with the H2AK13/15 ubiquitylation being particularly important for recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of DSBs. RNF8 mediates the ubiquitination of gammaH2AX, and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DNA damage response (DDR) and inhibits chromosomal instability. Moreover, RNF8 interacts with retinoid X receptor alpha (RXR alpha) and enhances its transcription-stimulating activity. It also regulates the rate of exit from mitosis and cytokinesis. RNF8 contains an N-terminal forkhead-associated (FHA) domain and a C-terminal C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*....|...
gi 1799133748  23 ELQCTIClstrfsQECRIEG----CNHSFCFSCISEWvcQSLRPSCPMCRKDV 71
Cdd:cd16535     1 ELQCSIC------SELFIEAvtlnCSHSFCSYCITEW--MKRKKECPICRKPI 45

RING finger, H2 subclass, found in RING finger protein 103 (RNF103) and similar proteins; RNF103, also known as KF-1 or zinc finger protein 103 homolog (Zfp-103), is an endoplasmic reticulum (ER)-resident E3 ubiquitin-protein ligase that is widely expressed in many different organs, including brain, heart, kidney, spleen, and lung. It is involved in the ER-associated degradation (ERAD) pathway by interacting with components of the ERAD pathway, including Derlin-1 and VCP. RNF103 contains several hydrophobic regions at its N-terminal and middle regions, as well as a C-terminal C3H2C3-type RING-H2 finger.

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                  ....*....|....*....|....*....|....*....|....*....|..
gi 1799133748  22 EELQCTICLSTrFSQECRIEG--CNHSFCFSCISEWVcQSLRPSCPMCRKDV 71
Cdd:cd16473     3 ECEECAICLEN-YQNGDLLRGlpCGHVFHQNCIDVWL-ERDNHCCPVCRWPV 52

RING finger, HC subclass, found in tripartite motif-containing protein 62 (TRIM62) and similar proteins; TRIM62, also known as Ductal Epithelium Associated Ring Chromosome 1 (DEAR1), is a cytoplasmic E3 ubiquitin-protein ligase that was identified as a dominant regulator of acinar morphogenesis in the mammary gland. It is implicated in the inflammatory response of immune cells by regulating the Toll-like receptor 4 (TLR4) signaling pathway, leading to increased activity of the activator protein 1 (AP-1) transcription factor in primary macrophages. It is also involved in muscular protein homeostasis, especially during inflammation-induced atrophy, and may play a role in the pathogenesis of ICU-acquired weakness (ICUAW) by activating and maintaining inflammation in myocytes. Moreover, TRIM62 facilitates K27-linked poly-ubiquitination of CARD9 and also regulates CARD9-mediated anti-fungal immunity and intestinal inflammation. It also functions as a chromosome 1p35 tumor suppressor and negatively regulates transforming growth factor beta (TGFbeta)-driven epithelial-mesenchymal transition (EMT) by binding to and promoting the ubiquitination of SMAD3, a major effector of TGFbeta-mediated EMT. TRIM62 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 1799133748  22 EELQCTICLSTrfSQECRIEGCNHSFCFSCISE-WVCQSLRpSCPMCRKD 70
Cdd:cd16608     5 DELLCSICLSI--YQDPVSLGCEHYFCRQCITEhWSRSEHR-DCPECRRT 51

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1799133748  24 LQCTICLST-RFSQECriEGCNHSFCFSCISEWVCQSlRPSCPMCR 68
Cdd:cd16619     1 FRCFICMEKlRDPRLC--PHCSKLFCKGCIRRWLSEQ-RSSCPHCR 43

RING finger, H2 subclass, found in rice E3 ubiquitin-protein ligase EL5 and similar proteins; EL5, also known as protein ELICITOR 5, is an E3 ubiquitin-protein ligase containing an N-terminal transmembrane domain and a C3H2C3-type RING-H2 finger that is a binding site for ubiquitin-conjugating enzyme (E2). It can be rapidly induced by N-acetylchitooligosaccharide elicitor. EL5 catalyzes polyubiquitination via the Lys48 residue of ubiquitin, and thus plays a crucial role as a membrane-anchored E3 in the maintenance of cell viability after the initiation of root primordial formation in rice. It also acts as an anti-cell death enzyme that might be responsible for mediating the degradation of cytotoxic proteins produced in root cells after the actions of phytohormones. Moreover, EL5 interacts with UBC5b, a rice ubiquitin carrier protein, through its RING-H2 finger. EL5 is an unstable protein, and its degradation is regulated by the C3H2C3-type RING-H2 finger in a proteasome-independent manner.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1799133748  25 QCTICLSTRFSQE--CRIEGCNHSFCFSCISEWVcqSLRPSCPMCR 68
Cdd:cd16461     1 ECAICLSDYENGEelRRLPECKHAFHKECIDEWL--KSNSTCPLCR 44

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.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1799133748  25 QCTICLSTrFS--QECRIEGCNHSFCFSCISEWVcqSLRPSCPMCR 68
Cdd:cd16454     1 TCAICLEE-FKegEKVRVLPCNHLFHKDCIDPWL--EQHNTCPLCR 43

Modified RING finger, H2 subclass (C3H2C2D-type), found in zinc finger SWIM domain-containing protein 2 (ZSWIM2) and similar proteins; ZSWIM2, also known as MEKK1-related protein X (MEX) or ZZ-type zinc finger-containing protein 2, is a testis-specific E3 ubiquitin ligase that promotes death receptor-induced apoptosis through Fas, death receptor (DR) 3 and DR4 signaling. ZSWIM2 is self-ubiquitinated and targeted for degradation through the proteasome pathway. It acts as an E3 ubiquitin ligase, through the E2, Ub-conjugating enzymes UbcH5a, UbcH5c, or UbcH6. ZSWIM2 contains four putative zinc-binding domains including an N-terminal SWIM (SWI2/SNF2 and MuDR) domain critical for its ubiquitination, and two modified RING-H2 fingers separated by a ZZ zinc finger domain, which was required for interaction with UbcH5a and its self-association. This model corresponds to the second RING-H2 finger, which is not a canonical C3H2C3-type, but a modified C3H2C2D-type.

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                  ....*....|....*....|....*....|....*....|....*...
gi 1799133748  25 QCTICLST-RFSQECRIEGCNHSFCFSCISEWVCQSlRPSCPMCRKDV 71
Cdd:cd16486     1 QCRICLKAfQLGQHVRTLPCRHKFHRDCIDNWLLHS-RNSCPIDGQVV 47

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 1799133748  22 EELQCTIClSTRFSQECRIEGCNHSFCFSCISewvcQSLR---PSCPMCRKDVDKV 74
Cdd:cd16620     2 DELKCPIC-KDLMKDAVLTPCCGNSFCDECIR----TALLeedFTCPTCKEPDVSP 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.

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                  ....*....|....*....|....*....|....*....|....*....|.
gi 1799133748  22 EELQCTICLSTrFSQECRIEgCNHSFCFSCISE-WVCQSLR-PSCPMCRKD 70
Cdd:cd16597     4 EELTCSICLEL-FKDPVTLP-CGHNFCGVCIEKtWDSQHGSeYSCPQCRAT 52

RING finger, HC subclass, found in RING finger protein 185 (RNF185) and similar proteins; RNF185 is an E3 ubiquitin-protein ligase of endoplasmic reticulum-associated degradation (ERAD) that targets cystic fibrosis transmembrane conductance regulator (CFTR). It controls the degradation of CFTR and CFTR F508del allele in a RING- and proteasome-dependent manner, but does not control that of other classical ERAD model substrates. It also negatively regulates osteogenic differentiation by targeting dishevelled2 (Dvl2), a key mediator of the Wnt signaling pathway, for degradation. Moreover, RNF185 regulates selective mitochondrial autophagy through interaction with the Bcl-2 family protein BNIP1. It also plays an important role in cell adhesion and migration through the modulation of cell migration by ubiquitinating paxillin. RNF185 contains a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*....|..
gi 1799133748  25 QCTICLSTrfSQECRIEGCNHSFCFSCISEWVcqSLRPS---CPMCRKDVDK 73
Cdd:cd16744     2 ECNICLDT--AKDAVVSLCGHLFCWPCLHQWL--ETRPNrqvCPVCKAGISR 49

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1799133748  22 EELQCTICLSTRfsQECRIEGCNH-SFCFSCISEWvcQSLRPSCPMCRKDVDKV 74
Cdd:pfam13920   1 EDLLCVICLDRP--RNVVLLPCGHlCLCEECAERL--LRKKKKCPICRQPIESV 50

RING finger, H2 subclass, found in RING finger proteins RNF24, RNF122, and similar proteins; This subfamily includes RNF24, RNF122, and similar proteins. RNF24 is an intrinsic membrane protein localized in the Golgi apparatus. It specifically interacts with the ankyrin-repeats domains (ARDs) of TRPC1, -3, -4, -5, -6, and -7, and affects TRPC intracellular trafficking without affecting their activity. RNF122 is a RING finger protein associated with HEK 293T cell viability. It is localized to the endoplasmic reticulum (ER) and the Golgi apparatus, and overexpressed in anaplastic thyroid cancer cells. RNF122 functions as an E3 ubiquitin ligase that can ubiquitinate itself and undergo degradation through its RING finger in a proteasome-dependent manner. Both RNF24 and RNF122 contain an N-terminal transmembrane domain and a C-terminal C3H2C3-type RING-H2 finger.

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                  ....*....|....*....|....*....|....*....|....*..
gi 1799133748  26 CTICLST-RFSQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCRKDV 71
Cdd:cd16469     3 CAVCLEEfKLKEELGVCPCGHAFHTKCLKKWL--EVRNSCPICKSPV 47

RING finger, HC subclass, found in Saccharomyces cerevisiae increased recombination centers protein 20 (IRC20) and similar proteins; IRC20 is an uncharacterized ATP-dependent helicase that is probably involved in a pathway contributing to genomic integrity. IRC20 contains a typical C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1799133748  23 ELQCTICLSTRFSQEcrIEGCNHSFCFSCISEWVCQslRPSCPMCR 68
Cdd:cd23135     3 KLSCSICFSEIRSGA--ILKCGHFFCLSCIASWLRE--KSTCPLCK 44

RING finger, HC subclass, found in Arabidopsis thaliana RING membrane-anchor proteins (AtRMAs) and similar proteins; AtRMAs, including AtRma1, AtRma2, and AtRma3, are endoplasmic reticulum (ER)-localized Arabidopsis homologs of human outer membrane of the ER-anchor E3 ubiquitin-protein ligase, RING finger protein 5 (RNF5). AtRMAs possess E3 ubiquitin ligase activity, and may play a role in the growth and development of Arabidopsis. The AtRMA1 and AtRMA3 genes are predominantly expressed in major tissues, such as cotyledons, leaves, shoot-root junction, roots, and anthers, while AtRMA2 expression is restricted to the root tips and leaf hydathodes. AtRma1 probably functions with the Ubc4/5 subfamily of E2. AtRma2 is likely involved in the cellular regulation of ABP1 expression levels through interacting with auxin binding protein 1 (ABP1). AtRMA proteins contain an N-terminal C3HC4-type RING-HC finger and a trans-membrane-anchoring domain in their extreme C-terminal region.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1799133748  26 CTICLSTrfSQECRIEGCNHSFCFSCISEWV-CQSLRPSCPMCR 68
Cdd:cd16745     3 CNICLDL--AQDPVVTLCGHLFCWPCLHKWLrRQSSQPECPVCK 44

RING finger, H2 subclass, found in RING finger protein 181 (RNF181) and similar proteins; RNF181, also known as HSPC238, is a platelet E3 ubiquitin-protein ligase containing a C3H2C3-type RING-H2 finger. It interacts with the KVGFFKR motif of platelet integrin alpha(IIb)beta3, suggesting a role for RNF181-mediated ubiquitination in integrin and platelet signaling. It also suppresses the tumorigenesis of hepatocellular carcinoma (HCC) through the inhibition of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling in the liver.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1799133748  25 QCTICLST-RFSQECRIEGCNHSFCFSCISEWVCQSlrPSCPMCR 68
Cdd:cd16669     1 KCPICLLEfEEGETVKQLPCKHSFHSDCILPWLGKT--NSCPLCR 43

RING finger, HC subclass, found in Caenorhabditis elegans BRCA1-associated RING domain protein 1 (CeBARD1) and similar proteins; CeBARD1, also called Ce-BRD-1, Cebrd-1, or RING-type E3 ubiquitin transferase BARD1, is a constituent of the CeBCD complex that possesses E3 ubiquitin-protein ligase activity. It plays a role in triggering cellular responses at damage sites in response to DNA damage that may be induced by ionizing radiation. It protects against chromosome non-disjunction and nuclear fragmentation during meiotic double-strand break repair to ensure sister chromatid recombination and aid chromosome stability. CeBARD1 contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1799133748  24 LQCTICLSTRFSQECrIEGCNHSFCFSCISEWVCQslRPSCPMCRKDVD 72
Cdd:cd23143     2 IECVICSEPQIDTFL-LSSCGHIYCWECFTEFIEK--RHMCPSCRFPLD 47

RING finger, HC subclass, found in RING finger protein 5 (RNF5) and similar proteins; RNF5, also known as protein G16 or Ram1, is an E3 ubiquitin-protein ligase anchored to the outer membrane of the endoplasmic reticulum (ER). It 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. It also regulates the turnover of specific G protein-coupled receptors by ubiquitinating JNK-associated membrane protein (JAMP) and preventing proteasome recruitment. RNF5 limits basal levels of autophagy and influences susceptibility to bacterial infection through the regulation of ATG4B stability. It is also involved in the degradation of Pendrin, a transmembrane chloride/anion exchanger highly expressed in thyroid, kidney, and inner ear. RNF5 plays an important role in cell adhesion and migration. It can modulate cell migration by ubiquitinating paxillin. Furthermore, RNF5 interacts with virus-induced signaling adaptor (VISA) at mitochondria in a viral infection-dependent manner, and further targets VISA at K362 and K461 for K48-linked ubiquitination and degradation after viral infection. It also negatively regulates virus-triggered signaling by targeting MITA, also known as STING, for ubiquitination and degradation at the mitochondria. In addition, RNF5 determines breast cancer response to ER stress-inducing chemotherapies through the regulation of the L-glutamine carrier proteins SLC1A5 and SLC38A2 (SLC1A5/38A2). It also has been implicated in muscle organization and in recognition and processing of misfolded proteins. RNF5 contains a C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1799133748  25 QCTICLSTrfSQECRIEGCNHSFCFSCISEWV-CQSLRPSCPMCRKDVDK 73
Cdd:cd16743     2 ECNICLET--ARDAVVSLCGHLFCWPCLHQWLeTRPERQECPVCKAGISR 49

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 1799133748  22 EELQCTICLStRFSQECRIEGCNHSFCFSCISEwvCQSLRPSCPMC 67
Cdd:cd16712     2 EEDECPICMD-RISNKKVLPKCKHVFCAACIDK--AMKYKPVCPVC 44

RING finger, H2 subclass, found in BRCA1-associated protein (BRAP2) and similar proteins; BRAP2, also known as impedes mitogenic signal propagation (IMP), RING finger protein 52, or renal carcinoma antigen NY-REN-63, is a novel cytoplasmic protein interacting with the two functional nuclear localization signal (NLS) motifs of BRCA1, a nuclear protein linked to breast cancer. It also binds to the SV40 large T antigen NLS motif and the bipartite NLS motif found in mitosin. BRAP2 serves as a cytoplasmic retention protein and plays a role in the regulation of nuclear protein transport. It contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), followed by a C3H2C3-type RING-H2 finger and a UBP-type zinc finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1799133748  25 QCTICLStrfsqecRIEG---------CNHSFCFSCISEWvCQSlrpSCPMCR 68
Cdd:cd16457     2 TCPVCLE-------RMDEsvsgiltilCNHSFHCSCLSKW-GDS---SCPVCR 43

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1799133748  22 EELQCTICLSTrFSQECRIEgCNHSFCFSCISE-WVCQSLRPSCPMC 67
Cdd:cd16580    10 EELICPICLHV-FVEPVQLP-CKHNFCRGCIGEaWAKDAGLVRCPEC 54

RING finger, H2 subclass, found in RING-box protein 2 (RBX2) and similar proteins; RBX2, also known as CKII beta-binding protein 1 (CKBBP1), RING finger protein 7 (RNF7), regulator of cullins 2 (ROC2), or sensitive to apoptosis gene protein (SAG), is an E3 ubiquitin-protein ligase that protects cells from apoptosis, confers radioresistance, and plays an essential and non-redundant role in embryogenesis and vasculogenesis. It promotes ubiquitination and degradation of a number of protein substrates, including c-JUN, DEPTOR, HIF-1alpha, IkappaBalpha, NF1, NOXA, p27, and procaspase-3, thus regulating various signaling pathways and biological processes. RBX2 is necessary for ubiquitin ligation activity of the multimeric cullin (Cul)-RING E3 ligases (CRLs). RBX2-containing CRLs are involved in the NEDD8 pathway and RBX2 specifically regulates NEDD8ylation of Cul5. It can bind and activate the HIV-1 Vif-Cullin5 E3 ligase complex in vitro. It is also a substrate of NEDD4-1 E3 ubiquitin ligase and mediates NEDD4-1 induced chemosensitization. The inactivation of RBX2 E3 ubiquitin ligase activity triggers senescence and inhibits Kras-induced immortalization. Endothelial deletion of RBX2 causes embryonic lethality and blocks tumor angiogenesis, and may have potential use in anti-angiogenesis therapy of human cancers. Moreover, as a component of the Cullin 5-RING E3 ubiquitin ligase (CRL5) complex, RBX2 regulates neuronal migration through different CRL5 adaptors, such as SOCS7. RBX2 also functions as a redox inducible antioxidant protein that scavenges oxygen radicals by forming inter- and intra-molecular disulfide bonds when acting alone. It contains a C-terminal C3H2C3-type RING-H2 finger that is essential for its ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1799133748  26 CTICLSTRFSQECRI--EGCNHSFCFSCISEWVCQSLRpsCPMCRKD 70
Cdd:cd16466    15 CLRCQAENKQEDCVVvwGECNHSFHNCCMSLWVKQNNR--CPLCQQD 59

RING finger, HC subclass, found in makorin-2 (MKRN2) and similar proteins; MKRN2, also known as makorin RING finger protein 2, RING finger protein 62 (RNF62), or HSPC070, is a putative ribonucleoprotein that acts as a neurogenesis inhibitor acting upstream of glycogen synthase kinase-3beta (GSK-3beta) in the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. It also functions in promoting cell proliferation of primary CD34+ progenitor cells and K562 cells, indicating its possible involvement in normal and malignant hematopoiesis. Mammalian MKRN2 contains three N-terminal C3H1-type zinc fingers, a motif rich in Cys and His residues (CH), a C3HC4-type RING-HC finger, and another C3H1-type zinc finger at the C-terminus. The third C3H1-type zinc finger, the CH motif, as well as the RING zinc finger are necessary for its anti-neurogenic activity.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1799133748  26 CTICLSTRFSQECRIE-------GCNHSFCFSCISEWVC-----QSLRPSCPMCR 68
Cdd:cd16731     4 CSICMEVVYEKASASErrfgilsNCNHTYCLSCIRQWRCakqfeNPIIKSCPECR 58

RING finger, H2 subclass, found in anaphase-promoting complex subunit 11 (APC11) and similar proteins; APC11, also known as cyclosome subunit 11, or hepatocellular carcinoma-associated RING finger protein, is a C3H2C3-type RING-H2 protein that facilitates ubiquitin chain formation by recruiting ubiquitin-charged ubiquitin conjugating enzymes (E2) through its RING-H2 domain. APC11 and its partner, the cullin-like subunit APC2, form the dynamic catalytic core of the gigantic, multisubunit 1.2-MDa anaphase-promoting complex/cyclosome (APC), also known as the cyclosome, which is a ubiquitin-protein ligase (E3) composed of at least 12 subunits and controls cell division by ubiquitinating cell cycle regulators, such as cyclin B and securin, to drive their timely degradation. APC11 can be inhibited by hydrogen peroxide, which may contribute to the delay in cell cycle progression through mitosis that is characteristic of cells subjected to oxidative stress. APC11 contains a canonical RING-H2-finger that coordinate two Zn2+ ions. In addition, it contains a third Zn2+-binding site that is not essential for its ligase activity.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1799133748  26 CTIClSTRFSQ---ECRIEG---------CNHSFCFSCISEWV-CQSLRPSCPMCRKD 70
Cdd:cd16456     4 CGIC-RMAFDGccpDCKFPGddcplvwgkCSHCFHMHCILKWLnSQQVQQHCPMCRQE 60

RING finger, HC subclass, found in RING finger protein 141 (RNF141) and similar proteins; RNF141, also known as zinc finger protein 230 (ZNF230), is a RING finger protein present primarily in the nuclei of spermatogonia, the acrosome, and the tail of spermatozoa. It may have a broad function during early development of vertebrates. It plays an important role in spermatogenesis, including spermatogenic cell proliferation and sperm maturation, as well as motility and fertilization. It also exhibits DNA binding activity. RNF141/ZNF230 gene mutations may be associated with azoospermia. RNF141 contains a C3HC4-type RING finger domain that may function as an activator module in transcription.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1799133748  25 QCTICLSTRFSQecrIEGCNHSFCFSCISEWVCQSlrPSCPMCR 68
Cdd:cd16545     2 ECCICMDRKADL---ILPCAHSYCQKCIDKWSDRH--RTCPICR 40

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
                  ....*....|....*....|....*....|....*....|....*..
gi 1799133748  23 ELQCTICLSTrFSQECRIEgCNHSFCFSCISEWVcqSLRPSCPMCRK 69
Cdd:cd23147     4 ELKCPICLSL-FKSAANLS-CNHCFCAGCIGESL--KLSAICPVCKI 46

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Deltex3 (DTX3) and similar proteins; DTX3, also known as RING finger protein 154 (RNF154), is an E3 ubiquitin-protein ligase that belongs to the Deltex (DTX) family. In contrast to other DTXs, DTX3 does not contain two N-terminal Notch-binding WWE domains, but a short unique N-terminal domain, suggesting it does not interact with the intracellular domain of Notch. Its C-terminal region includes a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1799133748  23 ELQCTICLSTrFSQECRIEGCNHSFCFSCISewvcQSLR--PSCPMCR 68
Cdd:cd16711     1 EETCPICLGE-IQNKKTLDKCKHSFCEDCIT----RALQvkKACPMCG 43

RING finger, HC subclass, found in zinc finger protein 598 (ZNF598) and similar proteins; ZNF598 associates with eukaryotic initiation factor 4E (eIF4E) homologous protein from mammals (m4EHP) by binding to Grb10-interacting GYF protein 2 (GIGYF2). The m4EHP-GIGYF2 complex functions as a translational repressor and is essential for normal embryonic development of mammalian. ZNF598 harbors a C3HC4-type RING-HC finger at its N-terminus.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1799133748  26 CTIClstrfSQECRIEG---CNHSFCFSCISE--WVCQSLRpsCPMCRKDVDKVSY 76
Cdd:cd16615     3 CVIC-----CEEIEYFAvgpCNHPVCYKCSLRmrVLYKDKY--CPICRTELDKVIF 51

Modified RING finger, HC subclass (C3HC3D-type), found in SR-related and CTD-associated factor 11 (SCAF11) and similar proteins; SCAF11, also known as CTD-associated SR protein 11 (CASP11), renal carcinoma antigen NY-REN-40, SC35-interacting protein 1 (Sip1), Serine/arginine-rich splicing factor 2 (SRSF2)-interacting protein, or splicing regulatory protein 129 (SRrp129), is a novel arginine-serine-rich (RS) domain-containing protein essential for pre-mRNA splicing. It functions as an auxiliary splice factor interacting with the spliceosomal component SC35, promoting RNAPII elongation. In addition to SR proteins, such as SC35, ASF/SF2, SRp75, and SRp20, SCAF11 also associates with U1-70K and U2AF65, proteins associated with 5' and 3' splice sites, respectively. SCAF11 contains an N-terminal modified C3HC3D-type RING-HC finger, an internal serine-arginine rich domain (SR domain), and a C-terminal SRI domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1799133748  26 CTICLSTRFSQECRI-EGCNHSFCFSCISEWVcqSLRPSCPMCRK 69
Cdd:cd16636     3 CPICLNCLLEQEVAFpENCSHVFCLTCILKWA--ETVTSCPIDRK 45

RING finger, H2 subclass, found in Arabidopsis thaliana protein SUGAR INSENSITIVE 3 (SIS3) and similar proteins; SIS3 is an E3 ubiquitin-protein ligase that acts as a positive regulator of sugar signaling during early seedling development. SIS3 contains a C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1799133748  26 CTICLSTrF--SQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCRKDV 71
Cdd:cd23118     3 CTICLED-FedGEKLRVLPCQHQFHSECVDQWL--RRNPKCPVCRRDA 47

RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins; COP1, also known as RING finger and WD repeat domain protein 2 (RFWD2) or RING finger protein 200 (RNF200), is a central regulator of photomorphogenic development in plants, which targets key transcription factors for proteasome-dependent degradation. It is localized predominantly in the nucleus, but may also be present in the cytosol. Mammalian COP1 functions as an E3 ubiquitin-protein ligase that interacts with Jun transcription factors and modulates their transcriptional activity. It also interacts with and negatively regulates the tumor-suppressor protein p53. Moreover, COP1 associates with COP9 signalosome subunit 6 (CSN6), and is involved in 14-3-3sigma ubiquitin-mediated degradation. The CSN6-COP1 link enhances ubiquitin-mediated degradation of p27(Kip1), a critical CDK inhibitor involved in cell cycle regulation, to promote cancer cell growth. Furthermore, COP1 functions as the negative regulator of ETV1 and influences prognosis in triple-negative breast cancer. COP1 contains an N-terminal extension, a C3HC4-type RING-HC finger, a coiled coil domain, and seven WD40 repeats. In human COP1, a classic leucine-rich NES, and a novel bipartite NLS is bridged by the RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1799133748  24 LQCTICLSTrfSQECRIEGCNHSFCFSCISEwvCQSLRPSCPMC 67
Cdd:cd16504     3 FLCPICFDI--IKEAFVTKCGHSFCYKCIVK--HLEQKNRCPKC 42

RING finger, HC subclass, found in bifunctional apoptosis regulator (BAR); BAR, also known as RING finger protein 47, was originally identified as an inhibitor of Bax-induced apoptosis. It participates in the block of apoptosis induced by TNF-family death receptors (extrinsic pathway) and mitochondria-dependent apoptosis (intrinsic pathway). BAR is predominantly expressed by neurons in the central nervous system and is involved in the regulation of neuronal survival. It is an endoplasmic reticulum (ER)-associated RING-type E3 ubiquitin ligase that interacts with BI-1 protein and post-translationally regulates its stability, as well as functioning in ER stress. BAR contains an N-terminal C3HC4-type RING-HC finger, a SAM domain, a coiled-coil domain, and a C-terminal transmembrane (TM) domain. This model corresponds to the RING-HC finger responsible for the binding of ubiquitin conjugating enzymes (E2s).

                          10        20
                  ....*....|....*....|....*..
gi 1799133748  43 CNHSFCFSCISEWVCQSLRPSCPMCRK 69
Cdd:cd16497    19 CGHSFCRHCLALWWKSSKKTECPECRQ 45

RING finger, HC subclass, found in RING finger protein 146 (RNF146) and similar proteins; RNF146, also known as dactylidin, or iduna, is a cytoplasmic E3 ubiquitin-protein ligase that is responsible for PARylation-dependent ubiquitination (PARdU). It displays neuroprotective property due to its inhibition of Parthanatos, a PAR dependent cell death, via binding with Poly(ADP-ribose) (PAR). It also modulates PAR polymerase-1 (PARP-1)-mediated oxidative cell injury in cardiac myocytes. Moreover, RNF146 mediates tankyrase-dependent degradation of axin, thereby positively regulating Wnt signaling. It also facilitates DNA repair and protects against cell death induced by DNA damaging agents or gamma-irradiation by translocating to the nucleus after cellular injury and promoting the ubiquitination and degradation of various nuclear proteins involved in DNA damage repair. Furthermore, RNF146 is implicated in neurodegenerative disease and cancer development. It regulates the development and progression of non-small cell lung cancer (NSCLC) by enhancing cell growth, invasion, and survival. RNF146 contains an N-terminal C3HC4-type RING-HC finger followed by a WWE domain with a poly(ADP-ribose) (PAR) binding motif at the tail.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1799133748  24 LQCTICLstrfsQECRIE---GCNHSFCFSCISEWVCQSLRpsCPMCRKDV 71
Cdd:cd16546     1 PECPICL-----QTCIHPvklPCGHIFCYLCVKGVAWQSKR--CALCRQEI 44

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM9, TRIM67, and similar proteins; Tripartite motif-containing proteins TRIM9 and TRIM67 belong to the C-I subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, consisting of three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, a fibronectin type III (FN3) domain, and a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. TRIM9 (the human ortholog of rat Spring), also known as RING finger protein 91 (RNF91), is a brain-specific E3 ubiquitin-protein ligase collaborating with an E2 ubiquitin conjugating enzyme UBCH5b. TRIM9 plays an important role in the regulation of neuronal functions and participates in neurodegenerative disorders through its ligase activity. TRIM67, also known as TRIM9-like protein (TNL), is a protein selectively expressed in the cerebellum. It interacts with PRG-1, an important molecule in the control of hippocampal excitability dependent on presynaptic LPA2 receptor signaling, and 80K-H, also known as glucosidase II beta, a protein kinase C substrate.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1799133748  22 EELQCTIClsTRFSQECRIEGCNHSFCFSCisewvCQSLRPSCPMCRK 69
Cdd:cd16576     2 EELKCPVC--GSLFTEPVILPCSHNLCLGC-----ALNIQLTCPICHK 42

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1799133748  24 LQCTICLSTrFSQECRIEGCNHSFCFSCISEwvcqSLRPSCPMCR 68
Cdd:cd16496    16 LRCSRCASI-LKEPVTLGGCEHVFCRSCVGD----RLGNGCPVCD 55

RING finger, H2 subclass, found in RING finger proteins RNF111, RNF165, and similar proteins; The family includes RING finger proteins RNF111, RNF165, and similar proteins. RNF111, also known as Arkadia, is a nuclear E3 ubiquitin-protein ligase that targets intracellular effectors and modulators of transforming growth factor beta (TGF-beta)/Nodal-related signaling for polyubiquitination and proteasome-dependent degradation. It also interacts with the clathrin-adaptor 2 (AP2) complex and regulates endocytosis of certain cell surface receptors, leading to modulation of epidermal growth factor (EGF) and possibly other signaling pathways. The N-terminal half of RNF111 harbors three SUMO-interacting motifs (SIMs). It thus functions as a SUMO-targeted ubiquitin ligase (STUbL) that directly links nonproteolytic ubiquitylation and SUMOylation in the DNA damage response, as well as triggers degradation of signal-induced polysumoylated proteins, such as the promyelocytic leukemia protein (PML). RNF165, also known as Arkadia-like 2, Arkadia2, or Ark2C, is an E3 ubiquitin ligase with homology to the C-terminal half of RNF111. It is expressed specifically in the nervous system, and can serve to amplify neuronal responses to specific signals. It acts as a positive regulator of bone morphogenetic protein (BMP)-Smad signaling that is involved in motor neuron (MN) axon elongation. Both RNF165 and RNF111 contain a C-terminal C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1799133748  26 CTICLST-RFSQECRIEGCNHSFCFSCISEWVcqSLRPSCPMCRKD 70
Cdd:cd16474     3 CTICLSDfEEGEDVRRLPCMHLFHQECVDQWL--STNKRCPICRVD 46

RING finger, H2 subclass, found in RING finger proteins RNF38, RNF44, and similar proteins; This subfamily includes RING finger proteins RNF38, RNF44, and similar proteins. RNF38 is a nuclear E3 ubiquitin protein ligase that plays a role in regulating p53. RNF44 is an uncharacterized RING finger protein that shows high sequence similarity to RNF38. Both RNF38 and RNF44 contain a coiled-coil motif, a KIL motif (Lys-X2-Ile/Leu-X2-Ile/Leu, X can be any amino acid), and a C3H2C3-type RING-H2 finger. In addition, RNF38 harbors two potential nuclear localization signals.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1799133748  22 EELQCTICLSTRFSQEC-RIEGCNHSFCFSCISEWVcQSLRpSCPMCR 68
Cdd:cd16472     1 DQTQCVVCMCDYEKRQLlRVLPCSHEFHAKCIDKWL-KTNR-TCPICR 46

RING finger, HC subclass, found in SH3 domain-containing RING finger proteins SH3RF1, SH3RF2, SH3RF3, and similar proteins; SH3RF1, also known as plenty of SH3s (POSH), RING finger protein 142 (RNF142), or SH3 multiple domains protein 2 (SH3MD2), is a trans-Golgi network-associated pro-apoptotic scaffold protein with E3 ubiquitin-protein ligase activity. SH3RF2, also known as heart protein phosphatase 1-binding protein (HEPP1), plenty of SH3s (POSH)-eliminating RING protein (POSHER), protein phosphatase 1 regulatory subunit 39, or RING finger protein 158 (RNF158), is a putative E3 ubiquitin-protein ligase that acts as an anti-apoptotic regulator for the c-Jun N-terminal kinase (JNK) pathway by binding to and promoting the proteasomal degradation of SH3RF1 (or POSH) that is required for pro-apoptotic JNK activation. SH3RF3, also known as plenty of SH3s 2 (POSH2) or SH3 multiple domains protein 4 (SH3MD4), is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in the screen for interacting partners of p21-activated kinase 2 (PAK2) and may play a role in regulating c-Jun N-terminal kinase (JNK) mediated apoptosis in certain conditions. Members of this subfamily contain an N-terminal C3HC4-type RING-HC finger responsible for the E3 ligase activity and four Src Homology 3 (SH3) domains, which are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs.

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gi 1799133748  24 LQCTICLStRFSQECRIEGCNHSFCFSCISEWVCQSLRPSCPMCR 68
Cdd:cd16570     1 LECPVCLE-RLDVSAKVLPCQHTFCKRCLQIIVASRGELRCPECR 44