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 1025327654 310 LRQLQEERTCKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVRAFMS 366
Cdd:cd16713     1 LRRLQEERTCKVCMDKEVSIVFIPCGHLVVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat domain; Found in inhibitors of apoptosis proteins (IAPs) and other proteins. In higher eukaryotes, BIR domains inhibit apoptosis by acting as direct inhibitors of the caspase family of protease enzymes. In yeast, BIR domains are involved in regulating cytokinesis. This novel fold is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues and resembles a classical zinc finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1025327654 197 DSRLSTYQNWPPGASVQPDALARAGFFYTGHDDNVKCFFCDGGLRNWEPGDDPWQEHAKWFPQCEYLL 264
Cdd:cd00022     1 EARLKTFKNWPISLKVTPEKLAEAGFYYTGRGDEVKCFFCGLELKNWEPGDDPWEEHKRWSPNCPFVL 68

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 1025327654 310 LRQLQEERTCKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVRAFMS 366
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 1025327654   82 SEDERLQTFQNWPTDAPVSPAELARAGFHYLGYSDTVQCFCCDGILRHWVHGDTPRGEHERHFPACGLMMG 152
Cdd:smart00238   1 SEEARLKTFQNWPYNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1025327654 315 EERTCKICMDKLVSMVFIPCGHLVVCTDCAASLR----HCPICRAVIRGS 360
Cdd:pfam13920   1 EDLLCVICLDRPRNVVLLPCGHLCLCEECAERLLrkkkKCPICRQPIESV 50

Baculoviral inhibition of apoptosis protein repeat domain; Found in inhibitors of apoptosis proteins (IAPs) and other proteins. In higher eukaryotes, BIR domains inhibit apoptosis by acting as direct inhibitors of the caspase family of protease enzymes. In yeast, BIR domains are involved in regulating cytokinesis. This novel fold is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues and resembles a classical zinc finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1025327654 197 DSRLSTYQNWPPGASVQPDALARAGFFYTGHDDNVKCFFCDGGLRNWEPGDDPWQEHAKWFPQCEYLL 264
Cdd:cd00022     1 EARLKTFKNWPISLKVTPEKLAEAGFYYTGRGDEVKCFFCGLELKNWEPGDDPWEEHKRWSPNCPFVL 68

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 1025327654 310 LRQLQEERTCKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVRAFMS 366
Cdd:cd16713     1 LRRLQEERTCKVCMDKEVSIVFIPCGHLVVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat domain; Found in inhibitors of apoptosis proteins (IAPs) and other proteins. In higher eukaryotes, BIR domains inhibit apoptosis by acting as direct inhibitors of the caspase family of protease enzymes. In yeast, BIR domains are involved in regulating cytokinesis. This novel fold is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues and resembles a classical zinc finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1025327654  84 DERLQTFQNWPTDAPVSPAELARAGFHYLGYSDTVQCFCCDGILRHWVHGDTPRGEHERHFPACGLMMG 152
Cdd:cd00022     1 EARLKTFKNWPISLKVTPEKLAEAGFYYTGRGDEVKCFFCGLELKNWEPGDDPWEEHKRWSPNCPFVLL 69

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 1025327654  86 RLQTFQNWP--TDAPVSPAELARAGFHYLGYSDTVQCFCCDGILRHWVHGDTPRGEHERHFPACGLMM 151
Cdd:pfam00653   1 RLATFENWPhsNKSPPTPEELAEAGFYYTGTGDRVQCFYCGLELDGWEEGDDPWEEHKKHSPDCPFLK 68

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1025327654 315 EERTCKICMDKLVSMVFIPCGHLVVCTDCAASLR----HCPICRAVIRGS 360
Cdd:pfam13920   1 EDLLCVICLDRPRNVVLLPCGHLCLCEECAERLLrkkkKCPICRQPIESV 50

RING finger, HC subclass, found in leucine-rich repeat and sterile alpha motif-containing protein 1 (LRSAM1) and similar proteins; LRSAM1, also known as Tsg101-associated ligase (TAL), or RIFLE, is an E3 ubiquitin-protein ligase that physically associates with, and selectively ubiquitylates, Tsg101, an E2-like molecule that regulates vesicular trafficking processes in yeast and mammals. It regulates a Tsg101-associated complex responsible for the sorting of cargo into cytoplasm-containing vesicles that bud at the multivesicular body and at the plasma membrane. LRSAM1 is a multidomain protein containing an N-terminal leucine-rich repeat (LRR), followed by several recognizable motifs, including an ezrin-radixin-moezin (ERM) domain, a coiled-coil (CC) region, a SAM domain, and a C-terminal C3HC4-type RING-HC finger domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVR 362
Cdd:cd16515     4 CVVCMDAESQVIFLPCGHVCCCQTCSSSLSTCPLCRADITQRVR 47

RING finger, HC subclass, found in Arabidopsis thaliana protein XB3 homolog 5 (XBAT35) and similar proteins; XBAT35, also known as ankyrin repeat domain and RING finger-containing protein XBAT35, or RING-type E3 ubiquitin transferase XBAT35, has no E3 ubiquitin-protein ligase activity observed when associated with the E2 enzyme UBC8 in vitro. It contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1025327654 318 TCKICMDKLVSMVFIPCGHLVVCTDCAASL----RHCPICRAVIRGSVRAF 364
Cdd:cd23129     4 ECVVCMDAPRDAVCVPCGHVAGCMSCLKALmqssPLCPICRAPVRQVIKVY 54

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 1025327654 314 QEERTCKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVRAFMS 366
Cdd:cd16706     2 SDDNLCRICMDAVIDCVLLECGHMVTCTKCGKRMSECPICRQYVVRAVHVFKS 54

RING finger, HC subclass, found in Dictyostelium discoideum Cbl-like protein A (CblA) and similar proteins; CblA is a Dictyostelium homolog of the Cbl proteins which are multi-domain proteins acting as key negative regulators of various receptor and non-receptor tyrosine kinase signaling. CblA upregulates STATc tyrosine phosphorylation by downregulating PTP3, the protein tyrosine phosphatase responsible for dephosphorylating STATc. STATc is a signal transducer and activator of transcription protein. Like other Cbl proteins, CblA contains a tyrosine-kinase-binding domain (TKB), a proline-rich domain, a C3HC4-type RING-HC finger, and an ubiquitin-associated (UBA) domain. TKB, also known as a phosphotyrosine binding PTB domain, is composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain. This family also includes Drosophila melanogaster defense repressor 1 (Dnr1) that was identified as an inhibitor of Dredd activity in the absence of a microbial insult in Drosophila S2 cells. It inhibits the Drosophila initiator caspases Dredd and Dronc. Moreover, Dnr1 acts as a negative regulator of the Imd (immune deficiency) innate immune-response pathway. Its mutations cause neurodegeneration in Drosophila by activating the innate immune response in the brain. Dnr1 contains a FERM N-terminal domain followed by a region rich in glutamine and serine residues, a central FERM domain, and a C-terminal C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICRAVIRGSVRAF 364
Cdd:cd16501     8 CVVCMDAPIDTVFLECGHLACCRLCSKRLRVCPICRQPISRVVRIF 53

second 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. Especially, 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 second RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1025327654 313 LQEERTCKICMDKLVSMVFiPCGHlVVCTDCAASLRHCPICRAVIRGSVRAFM 365
Cdd:cd16728     1 MEERITCPICIDNHIKLVF-QCGH-GSCIECSSALKACPICRQAIRERIQIFV 51

Modified RING finger, HC subclass (C3HC5-type), found in RING finger proteins, RNF26, RNF197 (CGRRF1), RNF156 (MGRN1), RNF157 and similar proteins; This subfamily corresponds to a group of RING finger proteins containing a 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. Cell growth regulator with RING finger domain protein 1 (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. RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination after viral infection and promoting degradation of IRF3, another important component required for virus-triggered interferon induction. Mahogunin ring finger-1 (MGRN1), also known as RING finger protein 156 (RNF156), is a cytosolic E3 ubiquitin-protein ligase that inhibits signaling through the G protein-coupled melanocortin receptors-1 (MC1R), -2 (MC2R) and -4 (MC4R) via ubiquitylation-dependent and -independent processes. It suppresses chaperone-associated misfolded protein aggregation and toxicity. RNF157 is a cytoplasmic E3 ubiquitin ligase predominantly expressed in the brain. It is a homolog of the E3 ligase MGRN1. In cultured neurons, it promotes neuronal survival in an E3 ligase-dependent manner. In contrast, it supports growth and maintenance of dendrites independent of its E3 ligase activity. RNF157 interacts with and ubiquitinates the adaptor protein APBB1 (amyloid beta precursor protein-binding, family B, member 1 or Fe65), which regulates neuronal survival, but not dendritic growth downstream of RNF157. The nuclear localization of APBB1 together with its interaction partner RNA-binding protein SART3 (squamous cell carcinoma antigen recognized by T cells 3 or Tip110) is crucial to trigger apoptosis.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCAASLRH--CPICR 354
Cdd:cd16649     1 GLCVVCLENPASVLLLPCRHLCLCEVCAKGLRGktCPICR 40

Modified RING finger, HC subclass (C3HC5-type), found in mahogunin RING finger protein 1 (MGRN1), RING finger protein 157 (RNF157) and similar proteins; MGRN1, also known as RING finger protein 156 (RNF156), is a cytosolic E3 ubiquitin-protein ligase that inhibits signaling through the G protein-coupled melanocortin receptors-1 (MC1R), -2 (MC2R) and -4 (MC4R) via ubiquitylation-dependent and -independent processes. It suppresses chaperone-associated misfolded protein aggregation and toxicity. MGRN1 interacts with cytosolic prion proteins (PrPs) that are linked with neurodegeneration. It also interacts with expanded polyglutamine proteins, and suppresses misfolded polyglutamine aggregation and cytotoxicity. Moreover, MGRN1 inhibits melanocortin receptor signaling by competition with Galphas, suggesting a novel pathway for melanocortin signaling from the cell surface to the nucleus. MGRN1 also interacts with and ubiquitylates TSG101, a key component of the endosomal sorting complex required for transport (ESCRT)-I, and regulates endosomal trafficking. A null mutation in the gene encoding MGRN1 causes spongiform neurodegeneration, suggesting a link between dysregulation of endosomal trafficking and spongiform neurodegeneration. RNF157 is a cytoplasmic E3 ubiquitin ligase predominantly expressed in the brain. It is a homolog of the E3 ligase mahogunin ring finger-1 (MGRN1). In cultured neurons, it promotes neuronal survival in an E3 ligase-dependent manner. In contrast, it supports growth and maintenance of dendrites independent of its E3 ligase activity. RNF157 interacts with and ubiquitinates the adaptor protein APBB1 (amyloid beta precursor protein-binding, family B, member 1 or Fe65), which regulates neuronal survival, but not dendritic growth downstream of RNF157. The nuclear localization of APBB1 together with its interaction partner RNA-binding protein SART3 (squamous cell carcinoma antigen recognized by T cells 3 or Tip110) is crucial to trigger apoptosis. Both MGRN1 and RNF157 contain a modified C3HC5-type RING-HC finger, and a functionally uncharacterized region, known as domain associated with RING2 (DAR2), N-terminal to the RING finger. The C3HC5-type RING-HC finger 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        40
                  ....*....|....*....|....*....|....*....|..
gi 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCAASLRH----CPICR 354
Cdd:cd16789     1 SECVICLSDPRDTAVLPCRHLCLCSDCAEVLRYqsnkCPICR 42

Modified RING finger, HC subclass (C3HC5-type), found in neuralized-like protein 1B (NEURL1B); NEURL1B, also known as neuralized-2 (NEUR2) or neuralized-like protein 3, is a mammalian homolog of the Drosophila neuralized (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 through working cooperatively with another E3 ligase, Mind bomb-1 (Mib1), in Delta endocytosis to hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs)-positive vesicles. NEURL1B contains 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 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRH-----CPICRAVIRGSVRAF 364
Cdd:cd16786     5 CTVCFDSEVDTVIYTCGHMCLCNSCGLKLKRqinacCPICRRVIKDVIKIY 55

RING finger, HC subclass, found in RNA-binding protein MEX3B; MEX3B, also known as RING finger and KH domain-containing protein 3 (RKHD3), or RING finger protein 195 (RNF195), 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 regulates the spatial organization of the Rap1 pathway that orchestrates Sertoli cell functions. It has a 3' long conserved untranslated region (3'LCU)-mediated fine-tuning system for mRNA regulation in early vertebrate development such as anteroposterior (AP) patterning and signal transduction. MEX3B 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, MEX3B shuttles between the nucleus and the cytoplasm via the CRM1-dependent export pathway.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCAASL-----RHCPICRAVIRGSVRAF 364
Cdd:cd16721     5 RDCSICFESEVIAALVPCGHNLFCMECANRIceknePQCPVCHAAVTQAIRIF 57

RING finger, HC subclass, found in mind bomb MIB1, MIB2, 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 first RING-HC finger of MIB1 and MIB2, as well as the second RING-HC finger of MIB1.

                          10        20        30
                  ....*....|....*....|....*....|....*.
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICR 354
Cdd:cd16519     3 CRVCSDKKALVLFQPCGHVVACEECSLRMKKCLQCK 38

Modified RING finger, HC subclass (C3HC5-type), found in RING finger protein 26 (RNF26) and similar proteins; RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination of MITA after viral infection, and promoting the degradation of IRF3, another important component required for virus-triggered interferon induction. Although RNF26 substrates of ubiquitination remain unclear at present, RNF26 upregulation in gastric cancer might be implicated in carcinogenesis through dysregulation of growth regulators. RNF26 contains an N-terminal leucine zipper domain and 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        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1025327654 314 QEERTCKICMDKLVSMVFIPCGHLVVCTDCAASL-------RHCPICRAVIR 358
Cdd:cd16788     3 RDKKKCVICQDQSKTVLILPCRHMCLCRQCANILlqqpvyrRNCPLCRTMIL 54

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        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1025327654 315 EERTCKICMDKLVSMVFiPCGHLVvCTDCAASLRHCPICRAVIRGSVRAF 364
Cdd:cd16729     1 DDQLCPICLSNPKDMAF-GCGHQT-CCECGQSLTHCPICRQPITTRIKLY 48

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 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCAASL-----RHCPICRAVIRGSVRAF 364
Cdd:cd16720     3 RDCMVCFESEVTAALVPCGHNLFCMECAVRIcernePECPVCHALATQAIRIF 55

Modified RING finger, HC subclass (C3HC5-type), found in mahogunin RING finger protein 1 (MGRN1) and similar proteins; MGRN1, also known as RING finger protein 156 (RNF156), is a cytosolic E3 ubiquitin-protein ligase that inhibits signaling through the G protein-coupled melanocortin receptors-1 (MC1R), -2 (MC2R) and -4 (MC4R) via ubiquitylation-dependent and -independent processes. It suppresses chaperone-associated misfolded protein aggregation and toxicity. MGRN1 interacts with cytosolic prion proteins (PrPs) that are linked with neurodegeneration. It also interacts with expanded polyglutamine proteins, and suppresses misfolded polyglutamine aggregation and cytotoxicity. Moreover, MGRN1 inhibits melanocortin receptor signaling by competition with Galphas, suggesting a novel pathway for melanocortin signaling from the cell surface to the nucleus. Furthermore, MGRN1 interacts with and ubiquitylates TSG101, a key component of the endosomal sorting complex required for transport (ESCRT)-I, and regulates endosomal trafficking. A null mutation in the gene encoding MGRN1 causes spongiform neurodegeneration, suggesting a link between dysregulation of endosomal trafficking and spongiform neurodegeneration. MGRN1 contains a modified C3HC5-type RING-HC finger, a conserved PSAP motif necessary for interaction between MGRN1 and TSG101. In addition, MGRN1 harbors a functionally uncharacterized region, as known as the domain associated with RING2 (DAR2), N-terminal to the RING finger. The C3HC5-type RING-HC finger 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        40
                  ....*....|....*....|....*....|....*....|....*
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRH----CPICRAVIRG 359
Cdd:cd16816    11 CVVCLSDLRDTLILPCRHLCLCNSCADTLRYqannCPICRLPFRA 55

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.

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                  ....*....|....*....|....*....|....*
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPIC 353
Cdd:cd16614     3 CMKCEERNRSVAVLPCQHYVLCEQCAETATECPYC 37

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
                  ....*....|....*....|....*....|....*....
gi 1025327654 319 CKICMDKLVSMVFIpCGHlVVCTDCAASLRHCPICRAVI 357
Cdd:cd16727     3 CPVCLDRLKNMIFL-CGH-GTCQLCGDRMSECPICRKAI 39

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.

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                  ....*....|....*....|....*....|....*....|....*....|...
gi 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCA-----ASLRHCPICRAVIRGSVRAF 364
Cdd:cd16723    11 RECVVCFESEVIAALVPCGHNLFCMECAiricgKSEPECPACHTPATQAIHIF 63

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.

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                  ....*....|....*....|....*....|....*....|.
gi 1025327654 319 CKICMDKLVSMVFIPCGHLvVCTDCAASLRH-----CPICR 354
Cdd:cd16502     4 CKICAENDKDVRIEPCGHL-LCTPCLTSWQDsdgqtCPFCR 43

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.

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                  ....*....|....*....|....*....|....*....|....*....|..
gi 1025327654 313 LQEERTCKICMDKLVSMVFIPCGH------LVVCTDCAASLRHCPICRAVIR 358
Cdd:cd16594     2 LQEELTCPICLDYFTDPVTLDCGHsfcracIARCWEEPETSASCPQCRETCP 53

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

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                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1025327654 313 LQEERTCKICMDKLVSMVFIPCGHlVVCTDCAASLRH---------CPICRAVIR 358
Cdd:cd16598     1 LEEEVTCSICLDYLRDPVTIDCGH-NFCRSCITDYCPisggherpvCPLCRKPFK 54

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.

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                  ....*....|....*....|....*....|....*...
gi 1025327654 317 RTCKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICR 354
Cdd:cd16772     1 KKCIVCQERDRSIVLQPCQHYVLCEHCAASKPECPYCK 38

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM43, TRIM48, TRIM49, TRIM51, TRIM64 and similar proteins; The family includes a group of closely related uncharacterized tripartite motif-containing proteins, TRIM43, TRIM43B, TRIM48/RNF101, TRIM49/RNF18, TRIM49B, TRIM49C/TRIM49L2, TRIM49D/TRIM49L, TRIM51/SPRYD5, TRIM64, TRIM64B, and TRIM64C, whose biological function remain unclear. TRIM49, also known as testis-specific RING-finger protein, has moderate similarity with SS-A/Ro52 antigen, suggesting it may be one of the target proteins of autoantibodies in the sera of patients with these autoimmune disorders. All family members 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 as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain. In RBCC region, they all have a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*....|.
gi 1025327654 314 QEERTCKICMDKLVSMVFIPCGH------LVVCTDCAASLRHCPICRAVIR 358
Cdd:cd16603     2 QRELTCPICMNYFIDPVTIDCGHsfcrpcLYLNWQDIPFLAQCPECRKTTE 52

first 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 first RING-HC finger.

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                  ....*....|....*....|....*....|....*.
gi 1025327654 319 CKICMDKLVSMVFIPCGHLVVCTDCAASLRHCPICR 354
Cdd:cd16724     3 CMVCSDMKRDTLFGPCGHIATCSLCSPRVKKCLICK 38

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

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gi 1025327654 319 CKICMDKLVSMVFIPCGHlVVCTDC----AASLRHCPICRAVI 357
Cdd:cd16546     3 CPICLQTCIHPVKLPCGH-IFCYLCvkgvAWQSKRCALCRQEI 44

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

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gi 1025327654 318 TCKICMDKLVSMVFIPCGHlVVCTDC------AASLRhCPICR 354
Cdd:cd16550     2 LCPICLEILVEPVTLPCNH-TLCMPCfqstveKASLC-CPLCR 42

RING finger, HC subclass, found in Saccharomyces cerevisiae POB3/SPT16 histone-associated protein 1 (ScPSH1) and similar proteins; ScPSH1 is a Cse4-specific E3 ubiquitin ligase that interacts with the kinetochore protein Pat1 and targets the degradation of budding yeast centromeric histone H3 variant, CENP-ACse4, which is essential for faithful chromosome segregation. ScPSH1 contains a C3HC4-type RING-HC finger and a DNA directed RNA polymerase domain.

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                  ....*....|....*....|....*....|....*....|....*..
gi 1025327654 318 TCKICMDKLVSMVFIPCGHLvVCTDCAASL------RHCPICRAVIR 358
Cdd:cd16568     6 ECIICHEYLYEPMVTTCGHT-YCYTCLNTWfksnrsLSCPDCRTKIT 51

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.

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                  ....*....|....*....|....*....|....*....|....*..
gi 1025327654 319 CKICMDKLVSMVFIPCGHLvVCTDCAASLRH-----CPICRAVIRGS 360
Cdd:cd16709    23 CKICAENDKDVKIEPCGHL-MCTSCLTAWQEsdgqgCPFCRCEIKGT 68

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.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1025327654 318 TCKICMD--KLVSMVFIPCGHLVVCTDCAASLRH----CPICRAVI 357
Cdd:cd16646     2 LCVICLSrpRTAAIVHGKTGHQVACYTCAKKLKRrgkpCPVCRRPI 47

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

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                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 1025327654 311 RQLQEERTCKICMDKLVSMVFIPCGHlVVCTDCAA---SLRH-----CPICRAVIRGSVR 362
Cdd:cd16623     3 NRLEMEATCPICLDFFSHPISLSCAH-IFCFDCIQkwmTKREdsiltCPLCRKEQKKPVL 61

RING finger, HC subclass, found in midline-1 (MID1) and similar proteins; MID1, also known as midin, midline 1 RING finger protein, putative transcription factor XPRF, RING finger protein 59 (RNF59), or tripartite motif-containing protein 18 (TRIM18), is a microtubule-associated E3 ubiquitin-protein ligase implicated in epithelial-mesenchymal differentiation, cell migration and adhesion, and programmed cell death along specific regions of the ventral midline during embryogenesis. It monoubiquinates the alpha4 subunit of protein phosphatase 2A (PP2A), promoting proteosomal degradation of the catalytic subunit of PP2A (PP2Ac) and preventing the A and B subunits from forming an active complex. It promotes allergen and rhinovirus-induced asthma through the inhibition of PP2A activity. It is strongly upregulated in cytotoxic lymphocytes (CTLs) and directs lytic granule exocytosis and cytotoxicity of killer T cells. Loss-of-function mutations in MID1 lead to the human X-linked Opitz G/BBB (XLOS) syndrome characterized by defective midline development during embryogenesis. MID1 belongs 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, including 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. MID1 hetero-dimerizes in vitro with its paralog MID2.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1025327654 313 LQEERTCKICMDKLVSMVFIPCGHlVVCTDCAASLR----------------HCPICRAVIRGSVRAF 364
Cdd:cd16753     2 LESELTCPICLELFEDPLLLPCAH-SLCFNCAHRILvshcasnesvesitafQCPTCRYVITLNQRGL 68