RING finger, HC subclass, found in apoptosis protein c-IAP1, c-IAP2, livin, and similar proteins; The cellular inhibitor of apoptosis protein c-IAPs function as ubiquitin E3 ligases that mediate the ubiquitination of substrates involved in apoptosis, nuclear factor-kappaB (NF-kappaB) signaling, and oncogenesis. Unlike other IAPs, such as XIAP, c-IAPs exhibit minimal binding to caspases and may not play an important role in the inhibition of these proteases. c-IAP1, also known as baculoviral IAP repeat-containing protein BIRC2, IAP-2, RING finger protein 48, or TNFR2-TRAF-signaling complex protein 2, is a potent regulator of the tumor necrosis factor (TNF) receptor family and NF-kappaB signaling pathways in the cytoplasm. It can also regulate E2F1 transcription factor-mediated control of cyclin transcription in the nucleus. c-IAP2, also known as BIRC3, IAP-1, apoptosis inhibitor 2 (API2), or IAP homolog C, also influences ubiquitin-dependent pathways that modulate innate immune signalling by activation of NF-kappaB. c-IAPs contain three N-terminal baculoviral IAP repeat (BIR) domains that enable interactions with proteins, a ubiquitin-association (UBA) domain that is responsible for the binding of polyubiquitin (polyUb), a caspase activation and recruitment domain (CARD) that serves as a protein interaction surface, and a C3HC4-type RING-HC finger at the carboxyl terminus that is required for ubiquitin ligase activity. Livin, also known as baculoviral IAP repeat-containing protein 7 (BIRC7), kidney inhibitor of apoptosis protein (KIAP), melanoma inhibitor of apoptosis protein (ML-IAP), or RING finger protein 50, was identified as the melanoma IAP. It plays crucial roles in apoptosis, cell proliferation, and cell cycle control. Its anti-apoptotic activity is regulated by the inhibition of caspase-3, -7, and -9. Its E3 ubiquitin-ligase-like activity promotes degradation of Smac/DIABLO, a critical endogenous regulator of all IAPs. Unlike other family members, mammalian livin contains a single BIR domain and a C3HC4-type RING-HC finger. The UBA domain can be detected in non-mammalian homologs of livin.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 11545910 225 LRRLQEERTCKVCLDRAVSIVFVPCGHL-VCAECAPGLQLCPICRAPVRSRVRTFLS 280
Cdd:cd16713   1 LRRLQEERTCKVCMDKEVSIVFIPCGHLvVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 11545910     86 SEELRLASFYDWPLTAEVPPELLAAAGFFHTGHQDKVRCFFCYGGLQSWKRGDDPWTEHAKWFPSCQFLLR 156
Cdd:smart00238   1 SEEARLKTFQNWPYNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

Inhibitor of Apoptosis domain; BIR stands for 'Baculovirus Inhibitor of apoptosis protein Repeat'. It is found repeated in inhibitor of apoptosis proteins (IAPs), and in fact it is also known as IAP repeat. These domains characteriztically have a number of invariant residues, including 3 conserved cysteines and one conserved histidine that coordinate a zinc ion. They are usually made up of 4-5 alpha helices and a three-stranded beta-sheet. BIR is also found in other proteins known as BIR-domain-containing proteins (BIRPs), such as Survivin.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 11545910    90 RLASFYDWPLTAEVPPEL--LAAAGFFHTGHQDKVRCFFCYGGLQSWKRGDDPWTEHAKWFPSCQFL 154
Cdd:pfam00653   1 RLATFENWPHSNKSPPTPeeLAEAGFYYTGTGDRVQCFYCGLELDGWEEGDDPWEEHKKHSPDCPFL 67

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 11545910    234 CKVCLDR-AVSIVFVPCGHLVCAECAPGLQL-----CPIC 267
Cdd:smart00184   1 CPICLEEyLKDPVILPCGHTFCRSCIRKWLEsgnntCPIC 40

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 11545910     86 SEELRLASFYDWPLTAEVPPELLAAAGFFHTGHQDKVRCFFCYGGLQSWKRGDDPWTEHAKWFPSCQFLLR 156
Cdd:smart00238   1 SEEARLKTFQNWPYNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

Inhibitor of Apoptosis domain; BIR stands for 'Baculovirus Inhibitor of apoptosis protein Repeat'. It is found repeated in inhibitor of apoptosis proteins (IAPs), and in fact it is also known as IAP repeat. These domains characteriztically have a number of invariant residues, including 3 conserved cysteines and one conserved histidine that coordinate a zinc ion. They are usually made up of 4-5 alpha helices and a three-stranded beta-sheet. BIR is also found in other proteins known as BIR-domain-containing proteins (BIRPs), such as Survivin.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 11545910    90 RLASFYDWPLTAEVPPEL--LAAAGFFHTGHQDKVRCFFCYGGLQSWKRGDDPWTEHAKWFPSCQFL 154
Cdd:pfam00653   1 RLATFENWPHSNKSPPTPeeLAEAGFYYTGTGDRVQCFYCGLELDGWEEGDDPWEEHKKHSPDCPFL 67

RING finger, HC subclass, found in inhibitor of apoptosis proteins (IAPs); IAPs are frequently overexpressed in cancer and associated with tumor cell survival, chemoresistance, disease progression, and poor prognosis. They function primarily as negative regulators of cell death. They regulate caspases and apoptosis through the inhibition of specific members of the caspase family of cysteine proteases. In addition, IAPs has been implicated in a multitude of other cellular processes, including inflammatory signalling and immunity, mitogenic kinase signalling, proliferation and mitosis, as well as cell invasion and metastasis. IAPs in this family includes cellular inhibitor of apoptosis protein c-IAP1 (BIRC2) and c-IAP2 (BIRC3), XIAP (BIRC4), BIRC7, and BIRC8, all of which contain three N-terminal baculoviral IAP repeat (BIR) domains that enable interactions with proteins, a ubiquitin-association (UBA) domain that is responsible for the binding of polyubiquitin (polyUb), and a C3HC4-type RING-HC finger at the carboxyl terminus that is required for ubiquitin ligase activity. The UBA domain is only absent in mammalian homologs of BIRC7. Moreover, c-IAPs contains an additional caspase activation and recruitment domain (CARD) between the UBA and C3HC4-type RING-HC domains. The CARD domain may serve as a protein interaction surface.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|
gi 11545910 231 ERTCKVCLDRAVSIVFVPCGHLV-CAECAPGLQLCPICRA 269
Cdd:cd16510   1 EKLCKICMDREVNIVFLPCGHLVtCAQCAASLRKCPICRT 40

Modified RING finger, HC subclass (C3HC5-type), found in neuralized-like protein NEURL1A, NEURL1B, and similar proteins; This subfamily includes Drosophila neuralized (D-neu) protein, and its two mammalian homologs, NEURL1A and NEURL1B. D-neu is a regulator of the developmentally important Notch signaling pathway. NEURL1A, also known as NEURL1, NEU, neuralized 1, or RING finger protein 67 (RNF67), is a mammalian homolog of D-neu. It functions as an E3 ubiquitin-protein ligase that directly interacts with and monoubiquitinates cytoplasmic polyadenylation element-binding protein 3 (CPEB3), an RNA binding protein and a translational regulator of local protein synthesis, which facilitates hippocampal plasticity and hippocampal-dependent memory storage. It also acts as a potential tumor suppressor that causes apoptosis and downregulates Notch target genes in medulloblastoma. NEURL1B, also known as neuralized-2 (NEUR2) or neuralized-like protein 3, is another mammalian homolog of D-neu protein. It functions as an E3 ubiquitin-protein ligase that interacts with and ubiquitinates Delta. Thus, it plays a role in the endocytic pathways for Notch signaling by working cooperatively with another E3 ligase, Mind bomb-1 (Mib1), in Delta endocytosis to hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs)-positive vesicles. Members of this subfamily contain two neuralized homology regions (NHRs) responsible for Neural-ligand interactions and a modified C3HC5-type RING-HC finger required for ubiquitin ligase activity. The C3HC5-type RING-HC finger is distinguished from typical C3HC4-type RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 11545910 233 TCKVCLDRAVSIVFVPCGHL-VCAECA----PGLQLCPICRAPVRSRVRTF 278
Cdd:cd16647   3 ECVICYERPVDTVLYRCGHMcMCYDCAlqlkRRGGSCPICRAPIKDVIKIY 53

RING finger, HC subclass, found in caspases-8 and -10-associated RING finger protein CARP-1, CARP-2 and similar proteins; The CARP subfamily includes CARP-1 and CARP-2 proteins, both of which are E3 ubiquitin ligases that ubiquitinate apical caspases and target them for proteasome-mediated degradation. As a novel group of caspase regulators with a FYVE-type zinc finger domain, they do not localize to membranes in the cell and are involved in the negative regulation of apoptosis, specifically targeting two initiator caspases, caspase 8, and caspase 10. Moreover, they stabilize MDM2 by inhibiting MDM2 self-ubiquitination, as well as by targeting 14-3-3sigma for degradation. They work together with MDM2 to enhance p53 degradation, thereby inhibiting p53-mediated cell death. CARPs contain an N-terminal FYVE-like domain that can serve as a membrane-targeting or endosome localizing signal and a C-terminal C3HC4-type RING-HC finger domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 11545910 233 TCKVCLDRAVSIVFVPCGHLV-CAECAPGLQLCPICRAPVRSRVRTF 278
Cdd:cd16500   2 LCKICMDAAIDCVLLECGHMVtCTDCGKKLSECPICRQYVVRVVHFF 48

RING finger, HC subclass, found in RING domain ligase RGLG1, RGLG2 and similar proteins from plant; RGLG1 is a ubiquitously expressed E3 ubiquitin-protein ligase that interacts with UBC13 and, together with UBC13, catalyzes the formation of K63-linked polyubiquitin chains, which is involved in DNA damage repair. RGLG1 mediates the formation of canonical, K48-linked polyubiquitin chains that target proteins for degradation. It also regulates apical dominance by acting on the auxin transport proteins abundance. RGLG1 has overlapping functions with its closest sequelog, RGLG2. They both function as RING E3 ligases that interact with ethylene response factor 53 (ERF53) in the nucleus and negatively regulate the plant drought stress response. Members of this subfamily contain a Von Willebrand factor type A (vWA) domain and a C3HC4-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 11545910 230 EERTCKVCLDRAVSIVFvPCGHLVCAECAPGLQLCPICRAPVRSRVRTF 278
Cdd:cd16729   1 DDQLCPICLSNPKDMAF-GCGHQTCCECGQSLTHCPICRQPITTRIKLY 48

RING finger, HC subclass, found in Arabidopsis thaliana MND1-interacting protein 1 (MIP1) and similar proteins; This subfamily includes Arabidopsis thaliana MIP1, RING finger protein 4 (RF4) and RING finger protein 298 (RF298). MIP1 interacts with MND1, HOP2 and XRI1. RF4 and RF298 are putative E3 ubiquitin-protein ligase that may mediate E2-dependent protein ubiquitination. Members of this subfamily contain a typical C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 11545910 231 ERTCKVCLDRAVSIVFVPCGHLV-CAECA-----PGLQLCPICRAPVRSRVR 276
Cdd:cd23128   3 ERECVMCMEEERSVVFLPCAHQVvCSGCNdlhekKGMRECPSCRGEIQERIR 54

RING finger, HC subclass, found in mind bomb MIB1, MIB2, RGLG1, RGLG2, and similar proteins; MIBs are large, multi-domain E3 ubiquitin-protein ligases that promote ubiquitination of the cytoplasmic tails of Notch ligands. They are also responsible for TBK1 K63-linked ubiquitination and activation, promoting interferon production and controlling antiviral immunity. Moreover, MIBs selectively control responses to cytosolic RNA and regulate type I interferon transcription. Both MIB1 and MIB2 have similar domain architectures, which consist of two Mib-Herc2 domains flanking a ZZ zinc finger, a REP region including two tandem Mib repeats, an ANK region that spans ankyrin repeats, and a RNG region, where MIB1 and MIB2 contain three and two C3HC4-type RING-HC fingers, respectively. This model corresponds to the third RING-HC finger of MIB1, as well as the second RING-HC finger of MIB2. In addition to MIB1 and MIB2, the RING-HC fingers of RING domain ligase RGLG1, RGLG2 and similar proteins from plant are also included in this model. RGLG1 is a ubiquitously expressed E3 ubiquitin-protein ligase that interacts with UBC13 and, together with UBC13, catalyzes the formation of K63-linked polyubiquitin chains, which is involved in DNA damage repair. RGLG1 mediates the formation of canonical, K48-linked polyubiquitin chains that target proteins for degradation. It also regulates apical dominance by acting on the auxin transport proteins abundance. RGLG1 has overlapping functions with its closest sequelog, RGLG2. They both function as RING E3 ligases that interact with ethylene response factor 53 (ERF53) in the nucleus and negatively regulate the plant drought stress response. All RGLG proteins contain a Von Willebrand factor type A (vWA) domain and a C3HC4-type RING-HC finger.

                        10        20        30
                ....*....|....*....|....*....|....*...
gi 11545910 234 CKVCLDRAVSIVFVpCGHLVCAECAPGLQLCPICRAPV 271
Cdd:cd16520   3 CPICMERKKNVVFL-CGHGTCQKCAEKLKKCPICRKPI 39

third RING finger, HC subclass, found in mind bomb 1 (MIB1) and similar proteins; MIB1, also known as DAPK-interacting protein 1 (DIP-1) or zinc finger ZZ type with ankyrin repeat domain protein 2, is a large, multi-domain E3 ubiquitin-protein ligase that promotes ubiquitination of the cytoplasmic tails of Notch ligands, and thus plays an essential role in controlling metazoan development by Notch signaling. It is also involved in Wnt/beta-catenin signaling and nuclear factor (NF)-kappaB signaling, and has been implicated in innate immunity, neuronal function, genomic stability, and cell death. MIB1 contains an MZM region with two Mib-Herc2 domains flanking a ZZ zinc finger, a REP region including two tandem Mib repeats, an ANK region that spans ankyrin repeats, and a RNG region consisting of three C3HC4-type RING-HC fingers. This model corresponds to the third RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 11545910 234 CKVCLDRAVSIVFVpCGHLVCAECAPGLQLCPICRAPVRSRVRTF 278
Cdd:cd16727   3 CPVCLDRLKNMIFL-CGHGTCQLCGDRMSECPICRKAIEKRILLY 46

RING finger, HC subclass, found in caspases-8 and -10-associated RING finger protein 1 (CARP1) and similar proteins; CARP1, also known as caspase regulator CARP1, FYVE-RING finger protein Momo, RING finger homologous to inhibitor of apoptosis protein (RFI), RING finger protein 34 (RNF34), or RING finger protein RIFF, is a nuclear protein that functions as a specific E3 ubiquitin ligase for the transcriptional coactivator PGC-1alpha, a master regulator of energy metabolism and adaptive thermogenesis in the brown fat cell which negatively regulates brown fat cell metabolism. It is preferentially expressed in esophageal, gastric, and colorectal cancers, suggesting a possible association with the development of digestive tract cancers. It regulates the p53 signaling pathway by degrading 14-3-3 sigma and stabilizing MDM2. CARP1 does not localize to membranes in the cell and is involved in the negative regulation of apoptosis, specifically targeting two initiator caspases, caspase 8 and caspase 10. CARP1 contains an N-terminal FYVE-like domain and a C-terminal C3HC4-type RING-HC finger domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLV-CAECAPGLQLCPICRAPVRSRVRTFLS 280
Cdd:cd16706   2 SDDNLCRICMDAVIDCVLLECGHMVtCTKCGKRMSECPICRQYVVRAVHVFKS 54

RING finger, HC subclass, found in tripartite motif-containing proteins, TRIM7, TRIM11 and TRIM27, and similar proteins; TRIM7, TRIM11 and TRIM27, closely related tripartite motif-containing proteins, belong to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain. TRIM7, also known as glycogenin-interacting protein (GNIP) or RING finger protein 90 (RNF90), is an E3 ubiquitin-protein ligase that mediates c-Jun/AP-1 activation by Ras signalling. Its phosphorylation and activation by MSK1 in response to direct activation by the Ras-Raf-MEK-ERK pathway can stimulate TRIM7 E3 ubiquitin ligase activity in mediating Lys63-linked ubiquitination of the AP-1 coactivator RACO-1, leading to RACO-1 protein stabilization. Moreover, TRIM7 binds and activates glycogenin, the self-glucosylating initiator of glycogen biosynthesis. TRIM11, also known as protein BIA1, or RING finger protein 92 (RNF92), is an E3 ubiquitin-protein ligase involved in the development of the central nervous system. It is overexpressed in high-grade gliomas and promotes proliferation, invasion, migration and glial tumor growth. TRIM11 acts as a potential therapeutic target for congenital central hypoventilation syndrome (CCHS) by mediating the degradation of CCHS-associated polyalanine-expanded Phox2b. TRIM11 modulates the function of neurogenic transcription factor Pax6 through the ubiquitin-proteosome system, and thus plays an essential role for Pax6-dependent neurogenesis. It also binds to and destabilizes a key component of the activator-mediated cofactor complex (ARC105), humanin, a neuroprotective peptide against Alzheimer's disease-relevant insults, and further regulates ARC105 function in transforming growth factor beta (TGFbeta) signaling. Moreover, TRIM11 negatively regulates retinoic acid-inducible gene-I (RIG-I)-mediated interferon-beta (IFNbeta) production and antiviral activity by targeting TANK-binding kinase-1 (TBK1). It may contribute to the endogenous restriction of retroviruses in cells. It enhances N-tropic murine leukemia virus (N-MLV) entry by interfering with Ref1 restriction. It also suppresses the early steps of human immunodeficiency virus HIV-1 transduction, resulting in decreased reverse transcripts. TRIM27, also known as RING finger protein 76 (RNF76), RET finger protein (RFP), or zinc finger protein RFP, is a nuclear E3 ubiquitin-protein ligase that is highly expressed in testis and in various tumor cell lines. Expression of TRIM27 is associated with prognosis of colon and endometrial cancers. TRIM27 was first identified as a fusion partner of the RET receptor tyrosine kinase. It functions as a transcriptional repressor and associates with several proteins involved in transcriptional activity, such as enhancer of polycomb 1 (Epc1), a member of the Polycomb group proteins, and Mi-2beta, a main component of the nucleosome remodeling and deacetylase (NuRD) complex, and the cell cycle regulator retinoblastoma protein (RB1). It also interacts with HDAC1, leading to downregulation of thioredoxin binding protein 2 (TBP-2), which inhibits the function of thioredoxin. Moreover, TRIM27 mediates Pax7-induced ubiquitination of MyoD in skeletal muscle atrophy. In addition, it inhibits muscle differentiation by modulating serum response factor (SRF) and Epc1. TRIM27 promotes a non-canonical polyubiquitination of PTEN, a lipid phosphatase that catalyzes PtdIns(3,4,5)P3 (PIP3) to PtdIns(4,5)P2 (PIP2). It is an IKKepsilon-interacting protein that regulates IkappaB kinase (IKK) function and negatively regulates signaling involved in the antiviral response and inflammation. TRIM27 also forms a protein complex with MBD4 or MBD2 or MBD3, and thus plays an important role in the enhancement of transcriptional repression through MBD proteins in tumorigenesis, spermatogenesis, and embryogenesis. It is a component of an estrogen receptor 1 (ESR1) regulatory complex that is involved in estrogen receptor-mediated transcription in MCF-7 cells.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 11545910 227 RLQEERTCKVCLDRAVSIVFVPCGHLVCAEC-------APGLQLCPICRAPVRSRVR 276
Cdd:cd16594   1 SLQEELTCPICLDYFTDPVTLDCGHSFCRACiarcweePETSASCPQCRETCPQRNL 57

Modified RING finger, HC subclass (C3HC5-type), found in cell growth regulator with RING finger domain protein 1 (CGRRF1) and similar proteins; CGRRF1, also known as cell growth regulatory gene 19 protein (CGR19) or RING finger protein 197 (RNF197), functions as a novel biomarker to monitor endometrial sensitivity and response to insulin-sensitizing drugs, such as metformin, in the context of obesity. CGRRF1 contains a C-terminal modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 11545910 234 CKVCLDRAVSIVFVPCGHL-VCAECAPGLQLCPICR 268
Cdd:cd16787   3 CVVCQNAPVNRVLLPCRHAcVCDECFKRLQRCPMCR 38

Modified RING finger, HC subclass (C3HC5-type), found in mitochondrial-anchored protein ligase (MAPL) and similar proteins; MAPL, also known as MULAN, mitochondrial ubiquitin ligase activator of NFKB 1, E3 SUMO-protein ligase MUL1, E3 ubiquitin-protein ligase MUL1, growth inhibition and death E3 ligase (GIDE), putative NF-kappa-B-activating protein 266, or RING finger protein 218 (RNF218), is a multifunctional mitochondrial outer membrane protein involved in several processes specific to metazoan (multicellular animal) cells, such as NF-kappaB activation, innate immunity and antiviral signaling, suppression of PINK1/parkin defects, mitophagy in skeletal muscle, and caspase-dependent apoptosis. MAPL contains a unique BAM (beside a membrane)/GIDE (growth inhibition death E3 ligase) domain and a C-terminal modified cytosolic C3HC5-type RING-HC finger which is distinguished from typical C3HC4-type RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 11545910 234 CKVCLDRAVSIVFVPCGHL-VCAEC---APGLQLCPICRAPVrSRV 275
Cdd:cd16648   4 CVICLSNPRSCVFLECGHVcSCIECyeaLPSPKKCPICRSFI-KRV 48

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 11545910 225 LRRLQEERTCKVCLDRAVSIVFVPCGHLVCAEC-----APGLQLCPICRAP 270
Cdd:cd16596   3 LTMMWEEVTCPICLDPFVEPVSIECGHSFCQECisqvgKGGGSVCPVCRQR 53

RING finger, HC subclass, found in Casitas B-lineage lymphoma (Cbl) proteins; The Cbl adaptor protein family contains a small class of RING-type E3 ubiquitin ligases with oncogenic activity, which is represented by three mammalian members, c-Cbl, Cbl-b and Cbl-c, as well as two invertebrate Cbl-family proteins, D-Cbl in Drosophila and Sli-1 in C. elegans. Cbl proteins function as potent negative regulators of various signaling cascades in a wide range of cell types. They play roles in ubiquitinating activated tyrosine kinases and targeting them for degradation. D-Cbl associates with the Drosophila epidermal growth factor receptor (EGFR) and overexpression of D-Cbl in the eye of Drosophila embryos inhibits EGFR-dependent photoreceptor cell development. Sli-1 is a negative regulator of the Let-23 receptor tyrosine kinase, an EGFR homolog, in vulva development. Cbl proteins in this subfamily consist of a highly conserved N-terminal half that includes a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain) and a C3HC4-type RING-HC finger, both of which are required for Cbl-mediated downregulation of RTKs, and a divergent C-terminal region.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|
gi 11545910 234 CKVCLDRAVSIVFVPCGHLVCAECAPGLQL-----CPICR 268
Cdd:cd16502   4 CKICAENDKDVRIEPCGHLLCTPCLTSWQDsdgqtCPFCR 43

RING finger, HC subclass, found in RNA-binding protein MEX3A; MEX3A, also known as RING finger and KH domain-containing protein 4 (RKHD4), is an RNA-binding phosphoprotein that localizes in P-bodies and stress granules, which are two structures involved in the storage and turnover of mRNAs. It has been implicated in the regulation of tumorigenesis. It controls the polarity and stemness of intestinal epithelial cells through the post-transcriptional regulation of the homeobox transcription factor CDX2, which plays a crucial role in intestinal cell fate specification, both during normal development and in tumorigenic processes involving intestinal reprogramming. Moreover, it exhibits a transforming activity when overexpressed in gastric epithelial cells. MEX3A contains two K homology (KH) domains that provide RNA-binding capacity, and a C-terminal C3HC4-type RING-HC finger. Like other MEX-3 family proteins, MEX3A shuttles between the nucleus and the cytoplasm via the CRM1-dependent export pathway.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 11545910 232 RTCKVCLDRAVSIVFVPCGH-LVCAECAPGL-----QLCPICRAPVRSRVRTF 278
Cdd:cd16720   3 RDCMVCFESEVTAALVPCGHnLFCMECAVRIcernePECPVCHALATQAIRIF 55

RING finger, HC subclass, found in seven in absentia homolog 1 (SIAH1) and similar proteins; SIAH1, also known as Siah-1a, is an inducible E3 ubiquitin-protein ligase that contributes to proteasome-mediated degradation of multiple targets in numerous cellular processes including apoptosis, tumor suppression, cell cycle, axon guidance, transcription regulation, and tumor necrosis factor signaling. SIAH1 functions as a scaffolding protein and interacts with a variety of different substrates for ubiquitination and subsequent degradation. It regulates the oncoprotein p34SEI-1 polyubiquitination and its subsequent degradation in a p53-dependent manner, which mediates p53 preferential vitamin C cytotoxicity. It targets the nonreceptor tyrosine kinase activated Cdc42-associated kinase 1 (ACK1), a valid target in cancer therapy, for ubiquitinylation and proteasomal degradation. It also interacts with KLF10 and targets it for degradation. The CDK2 phosphorylation-mediated KLF10 dissociation from SIAH1 is linked to cell cycle progression. Moreover, SIAH1 is downregulated and associated with apoptosis and invasion in human breast cancer. It targets TAp73, a homolog of the tumor suppressor p53, for degradation. It is suppressed by hypoxia-inducible factor 1-alpha (HIF-1alpha) under hypoxic conditions to regulate TAp73 levels. It also promotes the migration and invasion of human glioma cells by regulating HIF-1alpha signaling under hypoxia. Furthermore, SIAH1 forms a protein complex with glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The apoptosis signal-regulating kinase 1 (ASK1) functions as an activator of the GAPDH-Siah1 stress-signaling cascade. It also plays an important role in ethanol-induced apoptosis in neural crest cells (NCCs). SIAH1 contains an N-terminal C3HC4-type RING-HC finger, two zinc-finger subdomains, and a C-terminal tumor necrosis factor (TNF) receptor associated factor (TRAF)-like substrate-binding domain (SBD) responsible for dimer formation.

                        10        20        30
                ....*....|....*....|....*....|....*...
gi 11545910 234 CKVCLDRAVS-IVFVPCGHLVCAECAPGLQLCPICRAP 270
Cdd:cd16751   8 CPVCFDYVLPpILQCQSGHLVCSNCRPKLTCCPTCRGP 45

RING finger, HC subclass, found in RING finger and SPRY domain-containing protein 1 (RSPRY1) and similar proteins; RSPRY1 is a hypothetical RING and SPRY domain-containing protein of unknown physiological function. Mutations in its corresponding gene RSPRY1 may associate with a distinct skeletal dysplasia syndrome. RSPRY1 contains a B30.2/SPRY domain and a C3HC4-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 11545910 231 ERTCKVCLDRAVSIVFVPCGHL-VCAECAPGLQLCPICRAPV 271
Cdd:cd16566   2 EDSCTLCFDKVADTELRPCGHSgFCMECALQLETCPLCRQPI 43

RING finger, HC subclass, found in RNA-binding protein MEX3D; MEX3D, also known as RING finger and KH domain-containing protein 1 (RKHD1), RING finger protein 193 (RNF193), or TINO, is an RNA-binding phosphoprotein that controls the stability of the transcripts coding for the anti-apoptotic protein BCL-2, and negatively regulates BCL-2 in HeLa cells. MEX3D contains two K homology (KH) domains that provide RNA-binding capacity, and a C-terminal C3HC4-type RING-HC finger. Like other MEX-3 family proteins, MEX3D shuttles between the nucleus and the cytoplasm via the CRM1-dependent export pathway.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 11545910 232 RTCKVCLDRAVSIVFVPCGH-LVCAECA-----PGLQLCPICRAPVRSRVRTF 278
Cdd:cd16723  11 RECVVCFESEVIAALVPCGHnLFCMECAiricgKSEPECPACHTPATQAIHIF 63

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 11545910 228 LQEERTCKVCLDRAVSIVFVPCGHLVCAEC---------APGLQLCPICRAPVR 272
Cdd:cd16598   1 LEEEVTCSICLDYLRDPVTIDCGHNFCRSCitdycpisgGHERPVCPLCRKPFK 54

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 11545910 228 LQEERTCKVCLDRAVSIVFVPCGHLVCAEC--------APGLQLCPICRAPVRSR 274
Cdd:cd16597   2 LEEELTCSICLELFKDPVTLPCGHNFCGVCiektwdsqHGSEYSCPQCRATFPRR 56

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 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLVCAEC--------APGLQLCPICRAPVRSR 274
Cdd:cd16609   1 EEELTCSICLGLYQDPVTLPCQHSFCRACiedhwrqkDEGSFSCPECRAPFPEG 54

RING finger, HC subclass, found in RING finger protein unkempt (UNK), unkempt-like (UNKL), and similar proteins; UNK, also known as zinc finger CCCH domain-containing protein 5, is a metazoan-specific zinc finger protein enriched in embryonic brains. It may play a broad regulatory role during the formation of the central nervous system (CNS). It is a sequence-specific RNA-binding protein required for early neuronal morphology. UNK is a neurogenic component of the mTOR pathway, and functions as a negative regulator of the timing of photoreceptor differentiation. It also specifically binds to Brg/Brm-associated factor BAF60b and promotes its ubiquitination in a Rac1-dependent manner. UNKL, also known as zinc finger CCCH domain-containing protein 5-like, is a putative E3 ubiquitin-protein ligase that may participate in a protein complex showing an E3 ligase activity regulated by RAC1. Both UNK and UNKL contain several tandem CCCH-type zinc fingers at the N-terminus, and a C3HC4-type RING-HC finger at its C-terminus.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 11545910 234 CKVCLDRAVSIVFVPCGHLV-CAECAPGLQLCPIC 267
Cdd:cd16614   3 CMKCEERNRSVAVLPCQHYVlCEQCAETATECPYC 37

RING finger, HC subclass, found in tripartite motif-containing protein 40 (TRIM40) and similar proteins; TRIM40, also known as probable E3 NEDD8-protein ligase or RING finger protein 35 (RNF35), is highly expressed in the gastrointestinal tract including the stomach, small intestine, and large intestine. It enhances neddylation of inhibitor of nuclear factor kappaB kinase subunit gamma (IKKgamma), inhibits the activity of nuclear factor-kappaB (NF-kappaB)-mediated transcription, and thus prevents inflammation-associated carcinogenesis in the gastrointestinal tract. TRIM40 belongs to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by an N-terminal RBCC (RING, Bbox, and coiled coil) domain, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as an uncharacterized region positioned C-terminal to the RBCC domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLVCAEC---------APGLQLCPICRAPVRSRV 275
Cdd:cd16583   3 DEEGVCPICQEPLKEAVSTDCGHLFCRMCltqhakkasASGVFSCPVCRKPCSEGV 58

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 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLVCAECAPGLQL-CPICR 268
Cdd:cd16576   1 EEELKCPVCGSLFTEPVILPCSHNLCLGCALNIQLtCPICH 41

RING finger, HC subclass, found in seven in absentia homolog 2 (SIAH2) and similar proteins; SIAH2 is an E3 ubiquitin-protein ligase that contributes to proteasome-mediated degradation of multiple targets in numerous cellular processes. It targets the ubiquitylation and degradation of tumor necrosis factor receptor-associated factor 2 (TRAF2) under stress conditions, which is required for the cell to commit to undergoing apoptosis. It is, therefore, a key regulator of TRAF2-dependent signaling in response to tumor necrosis factor-alpha (TNF-alpha) treatment and UV irradiation. SIAH2 modulates the polyubiquitination of G protein pathway suppressor 2 (GPS2), and targets it for proteasomal degradation. It is also a regulator of NF-E2-related factor 2 (Nrf2), a key regulator of cellular oxidative response, and contributes to the degradation of Nrf2 irrespective of its phosphorylation status. Moreover, SIAH2 contributes to castration-resistant prostate cancer (CRPC) by regulation of androgen receptor (AR) transcriptional activity. It enhances AR transcriptional activity and prostate cancer cell growth. Its stability can be regulated by AKR1C3. SIAH2 also inhibits tyrosine kinase-2 (TYK2)-STAT3 signaling in lung carcinoma cells. Furthermore, SIAH2 regulates obesity-induced adipose tissue inflammation by altering peroxisome proliferator-activated receptor gamma (PPAR gamma) protein levels and selectively regulating PPAR gamma activity. It also functions as a regulator of the nuclear hormone receptor RevErbalpha (Nr1d1) stability and rhythmicity, and overall circadian oscillator function. In addition, SIAH2 is an essential component of the hypoxia response Hippo signaling pathway and has been implicated in normal development and tumorigenesis. It modulates the hypoxia pathway upstream of hypoxia-induced transcription factor subunit HIF-1alpha, and therefore may play an important role in angiogenesis in response to hypoxic stress in endothelial cells. It also stimulates transcriptional coactivator YAP1 by destabilizing serine/threonine-protein kinase LATS2, a critical component of the Hippo pathway, in response to hypoxia. Meanwhile, SIAH2 is involved in regulation of tight junction integrity and cell polarity under hypoxia, through its regulation of apoptosis-stimulating proteins of p53 subunit 2 (ASPP2) stability. SIAH2 contains an N-terminal C3HC4-type RING-HC finger, two zinc-finger subdomains, and a C-terminal tumor necrosis factor (TNF) receptor associated factor (TRAF)-like substrate-binding domain (SBD) responsible for dimer formation.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....
gi 11545910 234 CKVCLDRAVS-IVFVPCGHLVCAECAPGLQLCPICRAPVRSRVR 276
Cdd:cd16752   6 CPVCFDYVLPpILQCQAGHLVCNQCRQKLSCCPTCRGPLTPSIR 49

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 11545910 230 EERTCKVCLDRAVSIVFV-PCGHLVCAEC-------APGLQLCPICRAPVRS 273
Cdd:cd16554   1 ESLTCPVCLDLYYDPYMCyPCGHIFCEPClrqlaksSPKNTPCPLCRTTIRR 52

RING finger, HC subclass, found in RING finger protein unkempt-like (UNKL) and similar proteins; UNKL, also known as zinc finger CCCH domain-containing protein 5-like, is a putative E3 ubiquitin-protein ligase that may participate in a protein complex showing an E3 ligase activity regulated by RAC1. It shows high sequence similarity with RING finger protein unkempt (UNK), which is a metazoan-specific zinc finger protein enriched in embryonic brains, and may play a broad regulatory role during the formation of the central nervous system (CNS). UNKL contains several CCCH-type zinc fingers at the N-terminus, and a C3HC4-type RING-HC finger at its C-terminus.

                        10        20        30
                ....*....|....*....|....*....|....*...
gi 11545910 232 RTCKVCLDRAVSIVFVPCGHLV-CAECAPGLQLCPICR 268
Cdd:cd16772   1 KKCIVCQERDRSIVLQPCQHYVlCEHCAASKPECPYCK 38

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

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 11545910 230 EERTCKVCLDRAVSIVFVPCGHLVCAEC----APGLQLCPICRAPV 271
Cdd:cd16561   1 GEQECSICLEDLNDPVKLPCDHVFCEECirqwLPGQMSCPLCRTEL 46

Modified RING finger, HC subclass (C2H2C4-type), found in E3 ubiquitin-protein ligase MDM2, protein MDM4 and similar proteins; MDM2 (also known as HDM2) and MDM4 (also known as MDMX or HDMX) are the primary p53 tumor suppressor negative regulators. They have non-redundant roles in the regulation of p53. MDM2 mainly functions to control p53 stability, while MDM4 controls p53 transcriptional activity. Both MDM2 and MDM4 contain an N-terminal p53-binding domain, a RanBP2-type zinc finger (zf-RanBP2) domain near the central acidic region, and a C-terminal modified C2H2C4-type RING-HC finger. Mdm2 can form homo-oligomers through its RING domain and displays E3 ubiquitin ligase activity that catalyzes the attachment of ubiquitin to p53 as an essential step in the regulation of its levels in cells. Despite its RING domain and structural similarity with MDM2, MDM4 does not homo-oligomerize and lacks ubiquitin-ligase function, but inhibits the transcriptional activity of p53. In addition, both their RING domains are responsible for the hetero-oligomerization, which is crucial for the suppression of P53 activity during embryonic development and the recruitment of E2 ubiquitin-conjugating enzymes. Moreover, MDM2 and MDM4 can be phosphorylated and destabilized in response to DNA damage stress. In response to ribosomal stress, MDM2-mediated p53 ubiquitination and degradation can be inhibited through the interaction with ribosomal proteins L5, L11, and L23. However, MDM4 is not bound to ribosomal proteins, suggesting its different response to regulation by small basic proteins such as ribosomal proteins and ARF.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 11545910 233 TCKVCLDRAVSIVFV--PCGHLV-CAECAPGL----QLCPICRAPV 271
Cdd:cd16646   2 LCVICLSRPRTAAIVhgKTGHQVaCYTCAKKLkrrgKPCPVCRRPI 47

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM41, TRIM52 and similar proteins; TRIM41 and TRIM52, two closely related tripartite motif-containing proteins, have dramatically expanded RING domains compared with the rest of the TRIM family proteins. TRIM41 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. In contrast, TRIM52 lacks the putative viral recognition SPRY/B30.2 domain, and thus has been classified to the C-V subclass of the TRIM family that contains only RBCC domains. TRIM41, also known as RING finger-interacting protein with C kinase (RINCK), is an E3 ubiquitin-protein ligase that promotes the ubiquitination of protein kinase C (PKC) isozymes in cells. It specifically recognizes the C1 domain of PKC isozymes. It controls the amplitude of PKC signaling by controlling the amount of PKC in the cell. TRIM52, also known as RING finger protein 102 (RNF102), is encoded by a novel, noncanonical antiviral TRIM52 gene in primate genomes with unique specificity determined by the rapidly evolving RING domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLVCAECAPGLQ--LCPICR 268
Cdd:cd16602   1 QEEAVCAICLDYFKDPVSIGCGHNFCRVCVTQLWgfTCPQCR 42

first RING finger, HC subclass, found in mind bomb 2 (MIB2) and similar proteins; MIB2, also known as novel zinc finger protein (Novelzin), putative NF-kappa-B-activating protein 002N, skeletrophin, or zinc finger ZZ type with ankyrin repeat domain protein 1, is a large, multi-domain E3 ubiquitin-protein ligase that promotes ubiquitination of the cytoplasmic tails of Notch ligands. It promotes Delta ubiquitylation and endocytosis in Notch activation. Overexpression of MIB2 activates NF-kappaB and interferon-stimulated response element (ISRE) reporter activity. Moreover, MIB2 acts as a novel component of the activated B-cell CLL/lymphoma 10 (BCL10) complex and controls BCL10-dependent NF-kappaB activation. It also functions as a founder myoblast-specific protein that regulates myoblast fusion and muscle stability. MIB2 contains an MZM region with two Mib-Herc2 domains flanking a ZZ zinc finger, a REP region including two tandem Mib repeats, an ANK region that spans ankyrin repeats, and a RNG region consisting of two C3HC4-type RING-HC fingers. This model corresponds to the first RING-HC finger.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 11545910 234 CKVCLDRAVSIVFVPCGH-LVCAECAPGLQLCPIC 267
Cdd:cd16726   3 CLVCSELAALVRFEPCQHsIVCEECARRMKKCIKC 37

zinc-RING finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 11545910   234 CKVCLDRAVS---IVFVPCGHLVCAECAPGL---QLCPICR 268
Cdd:pfam14634   2 CNKCFKELSKtrpFYLTSCGHIFCEECLTRLlqeRQCPICK 42

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Cbl and similar proteins; Cbl, also known as Casitas B-lineage lymphoma proto-oncogene, proto-oncogene c-Cbl, RING finger protein 55 (RNF55), or signal transduction protein Cbl, is a multi-domain protein that acts as a key negative regulator of various receptor and non-receptor tyrosine kinase signaling. It contains a tyrosine kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain), a proline-rich domain, a C3HC4-type RING-HC finger, and an ubiquitin-associated (UBA) domain. TKB is responsible for the interactions with many tyrosine kinases, such as the colony-stimulating factor-1 (CSF-1) receptor, Syk/ZAP-70, and Src-family of protein tyrosine kinases. The proline-rich domain can recruit proteins with a SH3 domain. Moreover, Cbl functions as an E3 ubiquitin ligase that can bind ubiquitin-conjugating enzymes (E2s) through the RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....
gi 11545910 234 CKVCLDRAVSIVFVPCGHLVCAECAPGLQL-----CPICRAPVR 272
Cdd:cd16708  24 CKICAENDKDVKIEPCGHLMCTSCLTSWQEsegqgCPFCRCEIK 67

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Cbl-b and similar proteins; Cbl-b, also known as Casitas B-lineage lymphoma proto-oncogene b, RING finger protein 56 (RNF56), SH3-binding protein Cbl-b, or signal transduction protein Cbl-b, has been identified as a regulator of antigen-specific, T cell-intrinsic, peripheral immune tolerance, a state also known as clonal anergy. It may inhibit activation of the p85 subunit of phosphoinositide 3-kinase (PI3K), protein kinase C-theta (PKC-theta), and phospholipase C-gamma1 (PLC-gamma1) and negatively regulates T-cell receptor-induced transcription factor nuclear factor kappaB (NF-kappaB) activation. In addition, Cbl-b may target multiple signaling molecules involved in transforming growth factor (TGF)-beta-mediated transactivation pathways. Cbl-b contains a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, is composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain), a proline rich domain, a nuclear localization signal, a C3HC4-type RING-HC finger and an ubiquitin-associated (UBA) domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....
gi 11545910 234 CKVCLDRAVSIVFVPCGHLVCAECAPGLQL-----CPICRAPVR 272
Cdd:cd16709  23 CKICAENDKDVKIEPCGHLMCTSCLTAWQEsdgqgCPFCRCEIK 66

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 11545910    234 CKVCLDR-AVSIVFVPCGHLVCAECAPGLQL-----CPIC 267
Cdd:smart00184   1 CPICLEEyLKDPVILPCGHTFCRSCIRKWLEsgnntCPIC 40

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 11545910 229 QEERTCKVCLDRAVSIVFVPCGHLVCAECAPGLQ-------LCPICRAPVRSR 274
Cdd:cd23133   1 EETLTCSICQGIFMNPVYLRCGHKFCEACLLLFQedikfpaYCPMCRQPFNQE 53

RING finger, HC subclass, found in RING finger protein 166 (RNF166) and similar proteins; RNF166 is encoded by the gene RNF166 targeted by thyroid hormone receptor alpha1 (TRalpha1), which is important in brain development. It plays an important role in RNA virus-induced interferon-beta production by enhancing the ubiquitination of TRAF3 and TRAF6. RNF166, together with three closely related proteins: RNF114, RNF125 and RNF138, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM).

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*.
gi 11545910 233 TCKVCLD---RAVSIVfvPCGHLVCAEC-APGLQ----LCPICRAP 270
Cdd:cd16549   3 SCPICLEvyhKPVVIT--SCGHTFCGEClQPCLQvaspLCPLCRMP 46