Cysteine rich domain with multizinc binding regions; This is a cysteine rich domain which contains four zinc-binding regions (binding five zinc ions). Family members include human CHFR which interacts with Poly(ADP-ribose) (PAR) through a 20-amino acid PAR binding zinc finger region (PBZ) found at the C-terminal end of this cysteine-rich domain (i.e. the 4th region towards the C-terminal). CHFR lacking PBZ does not co-localize with nuclear PAR foci in interphase cells and cannot rescue antephase checkpoint function despite retaining autoubiquitination activity. Hence it has been suggested that the CHFR-PAR interaction is an important part of the antephase checkpoint and could form part of the checkpoint sensor for cellular stress and microtubule poisons or be required for proper localization of CHFR. The PBZ region of CHFR contains two adenine binding sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  326 SLPTAPD-YMCPLQGSHAICTCCFQPMPDRRaereqdPRVAPQQCAVCLQPFCHLYW-GCTRTGCFGCLAPFcELNLGDK 403
Cdd:pfam17979   3 QCGTAIGgFQCPPQTQHLQCTCCGGMMPDRR------DAGVPQQCLLCKRPFCGLYWgGCPRAGCQGCLKPF-SENLISK 75

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  404 CLDGVLNNNNYESDILKNYLATRGLTWKSVLTESLLALQRGVFM-------LSDYRITGNTVLCYCCGLRSFRELTYQYR 476
Cdd:pfam17979  76 IPDNVFNGNQYEQDILQDYLAQKGKTLQDVISEWLQKLDNGEIDrtrkplnLSDYIITADTPLCNDCALKLFSFLLYKYR 155

                  ...
gi 575771891  477 QNI 479
Cdd:pfam17979 156 ISI 158

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 575771891  139 NAQTSSE--DVKDASVKPdkMEETLTCIICQDLLHDCVsLQPCMHTFCAACYSGWMERSSLCPTCRCPVE--RICKNHIL 214
Cdd:TIGR00599   5 DITDSSDwlTTPIPSLYP--LDTSLRCHICKDFFDVPV-LTSCSHTFCSLCIRRCLSNQPKCPLCRAEDQesKLRSNWLV 81

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  215 NNLVEAYliqhpdksrseedvrsMDARNKITQDMLQPKVRRSFSD-----EEGSSEDLLELSDVDSESSDISQPYIVCRQ 289
Cdd:TIGR00599  82 SEIVESF----------------KNLRPSLLEFLRIPKTTPVENPdlagpENSSKIELIEESESDGVDAEDEDLQRSATS 145

                         170       180       190       200       210       220       230
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 575771891  290 CpeyRRQAVQSLPCPVPESelgatlalggEAPSTSASlptaPDYMC-PLQGSHAICTCCFQPMPDRRAEREQD 361
Cdd:TIGR00599 146 S---RALAARSTADILQLS----------SDPSKRND----ADYRSePPNEGLVQCPICQQRMPEKAVERHLD 201

Cysteine rich domain with multizinc binding regions; This is a cysteine rich domain which contains four zinc-binding regions (binding five zinc ions). Family members include human CHFR which interacts with Poly(ADP-ribose) (PAR) through a 20-amino acid PAR binding zinc finger region (PBZ) found at the C-terminal end of this cysteine-rich domain (i.e. the 4th region towards the C-terminal). CHFR lacking PBZ does not co-localize with nuclear PAR foci in interphase cells and cannot rescue antephase checkpoint function despite retaining autoubiquitination activity. Hence it has been suggested that the CHFR-PAR interaction is an important part of the antephase checkpoint and could form part of the checkpoint sensor for cellular stress and microtubule poisons or be required for proper localization of CHFR. The PBZ region of CHFR contains two adenine binding sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  326 SLPTAPD-YMCPLQGSHAICTCCFQPMPDRRaereqdPRVAPQQCAVCLQPFCHLYW-GCTRTGCFGCLAPFcELNLGDK 403
Cdd:pfam17979   3 QCGTAIGgFQCPPQTQHLQCTCCGGMMPDRR------DAGVPQQCLLCKRPFCGLYWgGCPRAGCQGCLKPF-SENLISK 75

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  404 CLDGVLNNNNYESDILKNYLATRGLTWKSVLTESLLALQRGVFM-------LSDYRITGNTVLCYCCGLRSFRELTYQYR 476
Cdd:pfam17979  76 IPDNVFNGNQYEQDILQDYLAQKGKTLQDVISEWLQKLDNGEIDrtrkplnLSDYIITADTPLCNDCALKLFSFLLYKYR 155

                  ...
gi 575771891  477 QNI 479
Cdd:pfam17979 156 ISI 158

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 575771891  162 TCIICQDLL--HDCVSLQPCMHTFCAACYSGWMERSSLCPTCR 202
Cdd:pfam13639   2 ECPICLEEFeeGDKVVVLPCGHHFHRECLDKWLRSSNTCPLCR 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 575771891   163 CIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSL-CPTC 201
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLESGNNtCPIC 40

HRD ubiquitin ligase complex, ER membrane component [Posttranslational modification, protein turnover, chaperones];

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 575771891 162 TCIICQDLLHDCVSLQ------------PCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:COG5243  289 TCTICMDEMFHPDHEPlprgldmtpkrlPCGHILHLHCLKNWLERQQTCPICRRPV 344

Cysteine rich domain with multizinc binding regions; This is a cysteine rich domain which contains four zinc-binding regions (binding five zinc ions). Family members include human CHFR which interacts with Poly(ADP-ribose) (PAR) through a 20-amino acid PAR binding zinc finger region (PBZ) found at the C-terminal end of this cysteine-rich domain (i.e. the 4th region towards the C-terminal). CHFR lacking PBZ does not co-localize with nuclear PAR foci in interphase cells and cannot rescue antephase checkpoint function despite retaining autoubiquitination activity. Hence it has been suggested that the CHFR-PAR interaction is an important part of the antephase checkpoint and could form part of the checkpoint sensor for cellular stress and microtubule poisons or be required for proper localization of CHFR. The PBZ region of CHFR contains two adenine binding sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  326 SLPTAPD-YMCPLQGSHAICTCCFQPMPDRRaereqdPRVAPQQCAVCLQPFCHLYW-GCTRTGCFGCLAPFcELNLGDK 403
Cdd:pfam17979   3 QCGTAIGgFQCPPQTQHLQCTCCGGMMPDRR------DAGVPQQCLLCKRPFCGLYWgGCPRAGCQGCLKPF-SENLISK 75

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891  404 CLDGVLNNNNYESDILKNYLATRGLTWKSVLTESLLALQRGVFM-------LSDYRITGNTVLCYCCGLRSFRELTYQYR 476
Cdd:pfam17979  76 IPDNVFNGNQYEQDILQDYLAQKGKTLQDVISEWLQKLDNGEIDrtrkplnLSDYIITADTPLCNDCALKLFSFLLYKYR 155

                  ...
gi 575771891  477 QNI 479
Cdd:pfam17979 156 ISI 158

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
                 ....*....|....*....|....*....|....*....|....*.
gi 575771891 163 CIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCRCPVERI 208
Cdd:cd23130    3 CPICLDDPEDEAITLPCLHQFCYTCILRWLQTSPTCPLCKTPVTSI 48

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        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891 157 MEETLTCIICQDLLHDCVSLqPCMHTFCAACYSG-WME---RSSLCPTCRCPVER---ICKNHILNNLVE 219
Cdd:cd16597    2 LEEELTCSICLELFKDPVTL-PCGHNFCGVCIEKtWDSqhgSEYSCPQCRATFPRrpeLHKNTVLRNIVE 70

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 575771891 158 EETLTCIICQDLLHDCVSLqPCMHTFCAACYSGWMERSSL----CPTCRCPVE 206
Cdd:cd16609    1 EEELTCSICLGLYQDPVTL-PCQHSFCRACIEDHWRQKDEgsfsCPECRAPFP 52

RING finger, HC subclass, found in tripartite motif-containing protein 35 (TRIM35) and similar proteins; TRIM35, also known as hemopoietic lineage switch protein 5 (HLS5), is a putative hepatocellular carcinoma (HCC) suppressor that inhibits phosphorylation of pyruvate kinase isoform M2 (PKM2), which is involved in aerobic glycolysis of cancer cells and further suppresses the Warburg effect and tumorigenicity in HCC. It also negatively regulates Toll-like receptor 7 (TLR7)- and TLR9-mediated type I interferon production by suppressing the stability of interferon regulatory factor 7 (IRF7). Moreover, TRIM35 regulates erythroid differentiation by modulating globin transcription factor 1 (GATA-1) activity. TRIM35 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 575771891 158 EETLTCIICQDLLHDCVSLqPCMHTFCAACYSGWMER--SSLCPTCR--CPVERICKNHILNNLVE 219
Cdd:cd16599    2 KEELLCPICYEPFREAVTL-RCGHNFCKGCVSRSWERqpRAPCPVCKeaSSSDDLRTNHTLNNLVE 66

RING finger, H2 subclass, found in synoviolin and similar proteins; Synoviolin, also known as synovial apoptosis inhibitor 1 (Syvn1), Hrd1, or Der3, is an endoplasmic reticulum (ER)-anchoring E3 ubiquitin ligase that functions as a suppressor of ER stress-induced apoptosis and plays a role in homeostasis maintenance. It also targets tumor suppressor gene p53 for proteasomal degradation, suggesting crosstalk between ER associated degradation (ERAD) and p53 mediated apoptotic pathway under ER stress. Moreover, synoviolin controls body weight and mitochondrial biogenesis through negative regulation of the thermogenic coactivator peroxisome proliferator-activated receptor coactivator (PGC)-1beta. It upregulates amyloid beta production by targeting a negative regulator of gamma-secretase, Retention in endoplasmic reticulum 1 (Rer1), for degradation. It is also involved in the degradation of endogenous immature nicastrin, and affects amyloid beta-protein generation. Moreover, synoviolin is highly expressed in rheumatoid synovial cells and may be involved in the pathogenesis of rheumatoid arthritis (RA). It functions as an anti-apoptotic factor that is responsible for the outgrowth of synovial cells during the development of RA. It promotes inositol-requiring enzyme 1 (IRE1) ubiquitination and degradation in synovial fibroblasts with collagen-induced arthritis. Furthermore, the upregulation of synoviolin may represent a protective response against neurodegeneration in Parkinson's disease (PD). In addition, synoviolin is involved in liver fibrogenesis. Synoviolin contains a C3H2C2-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 575771891 162 TCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCR 202
Cdd:cd16479    3 TCIICREEMTVGAKKLPCGHIFHLSCLRSWLQRQQTCPTCR 43

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
                 ....*....|....*....|....*....|....*....|....*..
gi 575771891 161 LTCIICQDLLHDCVSLQPCMHTFCAACYSGWMeRSSL--CPTCRCPV 205
Cdd:cd16531    2 LMCPICLGIIKNTMTVKECLHRFCAECIEKAL-RLGNkeCPTCRKHL 47

HC subclass of RING (RING-HC) finger 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 a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers 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 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 enables efficient transfer of ubiquitin from E2 to the substrates.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 575771891 161 LTCIICQDLLHDCVSLqPCMHTFCAACYSGWME-RSSLCPTC 201
Cdd:cd16449    1 LECPICLERLKDPVLL-PCGHVFCRECIRRLLEsGSIKCPIC 41

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 575771891 162 TCIICQD--LLHDCVSLQPCMHTFCAACYSGWMERSSLCPTC 201
Cdd:cd16468    1 ECVICMAdfVVGDPIRYLPCMHIYHVDCIDDWLMRSFTCPSC 42

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 575771891  159 ETLTCIICQDLLHDCVsLQPCMHT-FCAACYSGWMERSSLCPTCRCPVERI 208
Cdd:pfam13920   1 EDLLCVICLDRPRNVV-LLPCGHLcLCEECAERLLRKKKKCPICRQPIESV 50

RING finger, HC subclass, found in polycomb group RING finger protein 1 (PCGF1) and similar proteins; PCGF1, also known as nervous system Polycomb-1 (NSPc1) or RING finger protein 68 (RNF68), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR). It serves as the core component of a noncanonical Polycomb repressive complex 1 (PRC1)-like BCOR complex that also contains RING1, RNF2, RYBP, SKP1, as well as the BCL6 co-repressor BCOR and the histone demethylase KDM2B, and is required to maintain the transcriptionally repressive state of some genes, such as Hox genes, BCL6 and the cyclin-dependent kinase inhibitor, CDKN1A. PCGF1 promotes cell cycle progression and enhances cell proliferation as well. It is a cell growth regulator that acts as a transcriptional repressor of p21Waf1/Cip1 via the retinoid acid response element (RARE element). Moreover, PCGF1 functions as an epigenetic regulator involved in hematopoietic cell differentiation. It cooperates with the transcription factor runt-related transcription factor 1 (Runx1) in regulating differentiation and self-renewal of hematopoietic cells. Furthermore, PCGF1 represents a physical and functional link between Polycomb function and pluripotency. PCGF1 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 575771891 152 VKPDKMEETLTCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTC 201
Cdd:cd16733    1 VKIKDLNEHIVCYLCAGYFIDATTITECLHTFCKSCIVKYLQTSKYCPMC 50

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 575771891 158 EETLTCIICQDLLHDCVSLQpCMHTFCAACYSGWMERSSL---CPTCRCPV 205
Cdd:cd23133    1 EETLTCSICQGIFMNPVYLR-CGHKFCEACLLLFQEDIKFpayCPMCRQPF 50

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 575771891 163 CIICQDLLHDC--VSLQPCMHTFCAACYSGWME-RSSLCPTCR 202
Cdd:cd16448    1 CVICLEEFEEGdvVRLLPCGHVFHLACILRWLEsGNNTCPLCR 43

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
                 ....*....|....*....|....*....|....*....
gi 575771891 161 LTCIICQDLLHDCVsLQPCMHTFCAACYSGWMERSSLCP 199
Cdd:cd16637    2 LTCHICLQPLVEPL-DTPCGHTFCYKCLTNYLKIQQCCP 39

RING finger, HC subclass, found in Polycomb Group RING finger homologs (PCGF1, 2, 3, 4, 5 and 6), and similar proteins; This subfamily includes six Polycomb Group (PcG) RING finger homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) that use epigenetic mechanisms to maintain or repress expression of their target genes. They were first discovered in fruit flies and are well known for silencing Hox genes through modulation of chromatin structure during embryonic development. PCGF homologs play important roles in cell proliferation, differentiation, and tumorigenesis. They all have been found to associate with ring finger protein 2 (RNF2). The RNF2-PCGF heterodimer is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. Moreover, PCGF homologs are critical components in the assembly of distinct Polycomb Repression Complex 1 (PRC1) related complexes which is involved in the maintenance of gene repression and which target different genes through distinct mechanisms. The Drosophila PRC1 core complex is formed by the Polycomb (Pc), Polyhomeotic (Ph), Posterior sex combs (Psc), and Sex combs extra (Sce, also known as Ring) subunits. In mammals, the composition of PRC1 is much more diverse and varies depending on the cellular context. All PRC1 complexes contain homologs of the Drosophila Ring protein. Ring1A/RNF1 and Ring1B/RNF2 are E3 ubiquitin ligases that mark lysine 119 of histone H2A with a single ubiquitin group (H2AK119ub). Mammalian homologs of the Drosophila Psc protein, such as PCGF2/Mel-18 or PCGF4/BMI1, regulate PRC1 enzymatic activity. PRC1 complexes can be divided into at least two classes according to the presence or absence of CBX proteins, which are homologs of Drosophila Pc. Canonical PRC1 complexes contain CBX proteins that recognize and bind H3K27me3, the mark deposited by PRC2. Therefore, canonical PRC1 complexes and PRC2 can act together to repress gene transcription and maintain this repression through cell division. Non-canonical PRC1 complexes, containing RYBP (together with additional proteins, such as L3mbtl2 or Kdm2b) rather than the CBX proteins have recently been described in mammals. PCGF homologs contain a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 575771891 161 LTCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCR 202
Cdd:cd16525    1 LTCSLCKGYLIDATTITECLHSFCKSCIVRHLETSKNCPVCD 42

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 575771891 161 LTCIICQDLLHDCVSLqPCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:cd16514    2 LECSLCLRLLYEPVTT-PCGHTFCRACLERCLDHSPKCPLCRTSL 45

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
                 ....*....|....*....|....*....|....*....|....*....
gi 575771891 157 MEETLTCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:cd16529    1 LDDLLRCPICFEYFNTAMMITQCSHNYCSLCIRRFLSYKTQCPTCRAAV 49

first RING finger, HC subclass, found in Arabidopsis thaliana ORTHRUS and similar proteins; This subfamily includes Arabidopsis thaliana ORTHRUS 1-5. They are E3 ubiquitin-protein ligases that may participate in CpG methylation-dependent transcriptional regulation and/or epigenetic transcriptional silencing. ORTHRUS 1 mediates ubiquitination with the E2 ubiquitin-conjugating enzymes UBC11, UBC8 and UBC8 homologs (e.g. UBC10, UBC11, UBC28 and UBC29) but not with UBC27, UBC30, UBC32, UBC34 and UBC36. ORTHRUS 2 and 5 mediate ubiquitination with the E2 ubiquitin-conjugating enzyme UBC11. ORTHRUS 1 and 2 promote methylation-mediated gene silencing leading, for example, to early flowering. They can bind to CpG, CpNpG, and CpNpN DNA motifs, with a strong preference for methylated forms, and with highest affinity for CpG substrates. Members of this subfamily contain two typical C3HC4-type RING-HC fingers. This model corresponds to the first one.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 575771891 159 ETLTCIICQDLLHDCVSlQPCMHTFCAACYSGWMERSSL-CPTCRCPV 205
Cdd:cd23138    1 DELNCSFCMQLPERPVT-TPCGHNFCLKCFQKWMGQGKKtCGTCRSPI 47

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 575771891 162 TCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCRC 203
Cdd:cd16506    2 TCPICLDEIQNKKTLEKCKHSFCEDCIDRALQVKPVCPVCGV 43

RING finger found in polycomb group RING finger protein 4 (PCGF4) and similar proteins; PCGF4, also known as polycomb complex protein BMI-1 (B cell-specific Moloney murine leukemia virus integration site 1) or RING finger protein 51 (RNF51), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR). It serves as the core component of a canonical Polycomb repressive complex 1 (PRC1), which is composed of a chromodomain-containing protein (CBX2, CBX4, CBX6, CBX7 or CBX8) and a Polyhomeotic protein (PHC1, PHC2, or PHC3), and plays important roles in chromatin compaction and H2AK119 monoubiquitination. PCGF4 associates with the Runx1/CBFbeta transcription factor complex to silence target genes in a PRC2-independent manner. Moreover, PCGF4 is expressed in the hair cells and supporting cells. It can regulate cell survival by controlling mitochondrial function and reactive oxygen species (ROS) level in thymocytes and neurons, thus having an important role in the survival and sensitivity to ototoxic drug of auditory hair cells. Furthermore, PCGF4 controls memory CD4 T-cell survival through direct repression of Noxa gene in an Ink4a- and Arf-independent manner. It is required in neurons to suppress p53-induced apoptosis via regulating the antioxidant defensive response, and also involved in the tumorigenesis of various cancer types. PCGF4 contains a C3HC4-type RING-HC finger.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 575771891 152 VKPDKMEETLTCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCRCPVER 207
Cdd:cd16736    3 IKITELNPHLMCVLCGGYFIDATTIIECLHSFCKTCIVRYLETSKYCPICDVQVHK 58

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891 157 MEETLTCIICQDLLHDCVsLQPCMHTFCAACYSGWMERSSLCPTCRCPVE--RICKNHILNNLVEAYLIQHPdksrSEED 234
Cdd:COG5432   22 LDSMLRCRICDCRISIPC-ETTCGHTFCSLCIRRHLGTQPFCPVCREDPCesRLRGSSGSREINESHARNRD----LLRK 96

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 575771891 235 VRSMDARNKITQDMLQPKVRRSFSDEEGSSEDlleLSDVDSESSDISQPYIVCRQCPE-YRRQAVQSLPCP-----VP-- 306
Cdd:COG5432   97 VLESLCRLPRPIKEERPCRWETVIAQDSASGD---EEWEDDLASNSSPASIAKKTSRDsKKRKREDLVHCPacsnlVPhn 173

                        170       180
                 ....*....|....*....|....*
gi 575771891 307 --ESELGATLALGGEAPSTSASLPT 329
Cdd:COG5432  174 qiNQHLDSCLNSPSSPSSSSSPYKN 198

RING finger, H2 subclass, found in RING finger protein 165 (RNF165) and similar proteins; 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. RNF165 contains two serine rich domains, a nuclear localization signal, an NRG-TIER domain, and a C-terminal C3H2C3-type RING-H2 finger that is responsible for the enhancement of BMP-Smad1/5/8 signaling in the spinal cord.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 575771891 163 CIICQDLLHDCVSLQ--PCMHTFCAACYSGWMERSSLCPTCRCPVE 206
Cdd:cd16682   10 CTICLSMLEDGEDVRrlPCMHLFHQLCVDQWLAMSKKCPICRVDIE 55

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM5, TRIM6, TRIM22, TRIM34 and similar proteins; TRIM5, TRIM6, TRIM22, and TRIM34, four 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, 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. TRIM5, also known as RING finger protein 88 (RNF88), is a capsid-specific restriction factor that prevents infection from non-host-adapted retroviruses in a species-specific manner by binding to and destabilizing the retroviral capsid lattice before reverse transcription is completed. Its retroviral restriction activity correlates with the ability to activate TAK1-dependent innate immune signaling. TRIM5 also acts as a pattern recognition receptor that activates innate immune signaling in response to the retroviral capsid lattice. Moreover, TRIM5 plays a role in regulating autophagy through activation of autophagy regulator BECN1 by causing its dissociation from its inhibitors BCL2 and TAB2. It also plays a role in autophagy by acting as a selective autophagy receptor which recognizes and targets HIV-1 capsid protein p24 for autophagic destruction. TRIM6, also known as RING finger protein 89 (RNF89), is an E3-ubiquitin ligase that cooperates with the E2-ubiquitin conjugase UbE2K to catalyze the synthesis of unanchored K48-linked polyubiquitin chains, and further stimulates the interferon-I kappa B kinase epsilon (IKKepsilon) kinase-mediated antiviral response. It also regulates the transcriptional activity of Myc during the maintenance of embryonic stem (ES) cell pluripotency, and may act as a novel regulator for Myc-mediated transcription in ES cells. TRIM22, also known as 50 kDa-stimulated trans-acting factor (Staf-50) or RING finger protein 94 (RNF94), is an E3 ubiquitin-protein ligase that plays an integral role in the host innate immune response to viruses. It has been shown to inhibit the replication of a number of viruses, including HIV-1, hepatitis B, and influenza A. TRIM22 acts as a suppressor of basal HIV-1 long terminal repeat (LTR)-driven transcription by preventing the transcription factor specificity protein 1 (Sp1) binding to the HIV-1 promoter. It also controls FoxO4 activity and cell survival by directing Toll-like receptor 3 (TLR3)-stimulated cells toward type I interferon (IFN) type I gene induction or apoptosis. Moreover, TRIM22 can activate the noncanonical nuclear factor-kappaB (NF-kappaB) pathway by activating I kappa B kinase alpha (IKKalpha). It also regulates nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-kappaB. TRIM34, also known as interferon-responsive finger protein 1 or RING finger protein 21 (RNF21), may function as antiviral protein that contribute to the defense against retroviral infections.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 575771891 157 MEETLTCIICQDLLHDCVSLQpCMHTFCAACYSGWMERS------SLCPTCRC--PVERICKNHILNNLVE 219
Cdd:cd16591    3 IKEEVTCPICLELLTEPLSLD-CGHSFCQACITANHKESvnqegeSSCPVCRTsyQPENLRPNRHLANIVE 72

RING finger, H2 subclass, found in Saccharomyces cerevisiae transmembrane E3 ubiquitin-protein ligase 1 (TUL1) and similar proteins; This subfamily includes Saccharomyces cerevisiae TUL1, Schizosaccharomyces pombe DSC E3 ubiquitin ligase complex subunit 1 (DSC1), and Arabidopsis thaliana protein FLYING SAUCER 2 (FLY2). TUL1 is the catalytic component of DSC E3 ubiquitin ligase complexes that tag proteins present in Golgi, endosome and vacuole membranes and function in protein homeostasis under non-stress conditions, and support a role in protein quality control. It mediates ubiquitination of vacuolar proteins such as CPS1, PPN1, PEP12 and other proteins containing exposed hydrophilic residues within their transmembrane domains, leading to their sorting into internal vesicles in late endosomes. TUL1 also targets the unpalmitoylated endosomal SNARE TLG1 to the multivesicular body (MVB) pathway. DSC1, also known as defective for SREBP cleavage protein 1, is the catalytic component of the DSC E3 ubiquitin ligase complex required for the sre1 transcriptional activator proteolytic cleavage to release the soluble transcription factor from the membrane in low oxygen or sterol conditions. FLY2 acts as an E3 ubiquitin-protein ligase that may be involved in xylem development. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 575771891 157 MEETLTCIIC---------QDLLHDCVsLQPCMHTFCAACYSGWMERSSLCPTCRCP 204
Cdd:cd23117    1 ENGSVDCVICmsdielpstNSVRRDYM-VTPCNHIFHTNCLERWMDIKLECPTCRRP 56

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
                 ....*....|....*....|....*....|....*....|....*
gi 575771891 161 LTCIICQDLLHDCVsLQPCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:cd16562    2 ISCHICLGKVRQPV-ICSNNHVFCSSCMDVWLKNNNQCPACRVPI 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 575771891 162 TCIICQDLLHD--CVSLQPCMHTFCAACYSGWMERSSLCPTCRC 203
Cdd:cd23118    2 TCTICLEDFEDgeKLRVLPCQHQFHSECVDQWLRRNPKCPVCRR 45

RING finger, HC subclass, found in Dictyostelium discoideum Ras guanine nucleotide exchange factor O (RasGEFO) and similar proteins; RasGEFO, also known as RasGEF domain-containing protein O, functions as a Ras guanine-nucleotide exchange factor (RasGEFs), activating Ras by catalyzing the replacement of GDP with GTP. RasGEFs are particularly important for signaling in development and chemotaxis in many organisms, including Dictyostelium. RasGEFO contains a C3HC4-type RING-HC finger that may be responsible for E3 ubiquitin ligase activity.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 575771891 156 KMEETLTCIICQDLLHDCVSLQPCMHTFCAACYSGWMERSSlCPTCRCPV 205
Cdd:cd16507    5 NLLQSLTCGICQNLFKDPNTLIPCGHAFCLDCLTTNASIKN-CIQCKVEY 53

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 575771891 163 CIICQDLLHDCvsLQPCMHTFCAACYSGWMERSSLCPTCR 202
Cdd:cd16545    3 CCICMDRKADL--ILPCAHSYCQKCIDKWSDRHRTCPICR 40

RING finger, HC subclass, found in tripartite motif-containing protein 47 (TRIM47) and similar proteins; TRIM47, also known as gene overexpressed in astrocytoma protein (GOA) or RING finger protein 100 (RNF100), 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, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. It plays an important role in the process of dedifferentiation that is associated with astrocytoma tumorigenesis. This subfamily also includes RING finger protein 135 (RNF135). RNF135, also known as RIG-I E3 ubiquitin ligase (REUL) or Riplet, is a widely expressed E3 ubiquitin-protein ligase that consists of an N-terminal C3HC4-type RING-HC finger and C-terminal B30.2/SPRY and PRY motifs, but lacks the B-box and coiled-coil domains that are also typically present in TRIM proteins. RNF135 serves as a specific retinoic acid-inducible gene-I (RIG-I)-interacting protein that ubiquitinates RIG-I and specifically stimulates RIG-I-mediated innate antiviral activity to produce antiviral type-I interferon (IFN) during the early phase of viral infection. It also has been identified as a bio-marker and therapy target of glioblastoma. It associates with the ERK signal transduction pathway and plays a role in glioblastoma cell proliferation, migration and cell cycle.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 575771891 161 LTCIICQDLLHDCVSLqPCMHTFCAACYSG-WME---RSSLCPTCRCP 204
Cdd:cd16604    1 LSCPICLDLLKDPVTL-PCGHSFCMGCLGAlWGAgrgGRASCPLCRQT 47

HRD ubiquitin ligase complex, ER membrane component [Posttranslational modification, protein turnover, chaperones];

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 575771891 162 TCIICQDLLHDCVSLQ------------PCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:COG5243  289 TCTICMDEMFHPDHEPlprgldmtpkrlPCGHILHLHCLKNWLERQQTCPICRRPV 344

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 575771891 155 DKMEETLTCIICQDLLHDCVSLQpCMHTFCAACYSG-WMERSSLCPTCRCP 204
Cdd:cd16596    4 TMMWEEVTCPICLDPFVEPVSIE-CGHSFCQECISQvGKGGGSVCPVCRQR 53

RING finger, H2 subclass, found in Tetratricopeptide repeat protein 3 (TTC3) and similar proteins; TTC3, also known as protein DCRR1, TPR repeat protein D, TPR repeat protein 3, or RING finger protein 105 (RNF105), is an E3 ubiquitin-protein ligase encoded by a gene within the Down syndrome (DS) critical region on chromosome 21. It affects differentiation and Golgi compactness in neurons through specific actin-regulating pathways. It inhibits the neuronal-like differentiation of pheocromocytoma cells by activating RhoA and by binding to Citron proteins. TTC3 is an Akt-specific E3 ligase that binds to phosphorylated Akt and facilitates its ubiquitination and degradation within the nucleus. It contains four N-terminal TPR motifs, a potential coiled-coil region and a Citron binding region in the central part, and a C-terminal C3H2C2-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 575771891 163 CIICQD-LLHDCVSLQPCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:cd16481    2 CIICHDdLKPDQLAKLECGHIFHKECIKQWLKEQSTCPTCRVHV 45

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 575771891 158 EETLTCIICQDLLHDCVsLQPCMHTFCAACYSGWMERSSLCPTCRCPV 205
Cdd:cd23148    1 DHALRCHICKDLLKAPM-RTPCNHTFCSFCIRTHLNNDARCPLCKAEV 47

RING finger, HC subclass, found in RING finger and transmembrane domain-containing protein 1 (RNFT1); RNFT1, also known as protein PTD016, is a multi-pass membrane protein containing a C3HC4-type RING-HC finger. Its biological role remains unclear.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 575771891 163 CIICQDLLHDCVSLQpCMHTFCAACYSGWMERSSLCPTCR 202
Cdd:cd16741   17 CAICQAEFRKPILLI-CQHVFCEECISLWFNREKTCPLCR 55