RING finger (Really Interesting New Gene) domain and U-box domain superfamily; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers: some have different Cys/His patterns while some lack a single Cys or His residue at typical Zn ligand positions (the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can indeed chelate Zn in a RING finger as well). C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type RING fingers are closely related to RING-HC fingers. In contrast, C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type RING fingers are more closely related to RING-H2 fingers. However, not all RING finger-containing proteins display regular RING finger features, and the RING finger family has turned out to be multifarious. The degenerate RING fingers of the Siz/PIAS RING (SP-RING) family proteins and sporulation protein RMD5, are characterized by lacking the second, fifth, and sixth Zn2+ ion-coordinating residues. They bind only one Zn2+ ion. On the other hand, the RING fingers of the human APC11 and RBX1 proteins can bind a third Zn atom since they harbor four additional Zn ligands. U-box is a modified form of the RING finger domain that lacks metal chelating Cys and His residues. It resembles the cross-brace RING structure consisting of three beta-sheets and a single alpha-helix, which would be stabilized by salt bridges instead of chelated metal ions. U-box proteins are widely distributed among eukaryotic organisms and show a higher prevalence in plants than in other organisms. RING finger/U-box-containing proteins are a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enable efficient transfer of ubiquitin from E2 to the substrates.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 17542872 252 RPTCAICSTKYSKNCSTQTPRILDKCGHTLCEGCIQNILKHS-NQISCPICKSVT 305
Cdd:cd23124   1 ELECGICQQEYSADDPLLIPRILTECGHTICTNCAGTILGQSsGSIFCPFDRIVT 55

Modified RING finger, HC subclass (C3HC3D-type), found in Caenorhabditis elegans putative GTP-binding protein trim-23 homolog (arc-1) and similar proteins; arc-1, also called RING-type E3 ubiquitin transferase arc-1, is an E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. arc-1 contains a modified C3HC3D-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 17542872 252 RPTCAICSTKYSKNCSTQTPRILDKCGHTLCEGCIQNILKHS-NQISCPICKSVT 305
Cdd:cd23124   1 ELECGICQQEYSADDPLLIPRILTECGHTICTNCAGTILGQSsGSIFCPFDRIVT 55

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 17542872   255 CAICSTKYsKNCSTQTPrildkCGHTLCEGCIQNILKHSNQiSCPIC 301
Cdd:pfam00097   1 CPICLEEP-KDPVTLLP-----CGHLFCSKCIRSWLESGNV-TCPLC 40

Modified RING finger, HC subclass (C3HC3D-type), found in Caenorhabditis elegans putative GTP-binding protein trim-23 homolog (arc-1) and similar proteins; arc-1, also called RING-type E3 ubiquitin transferase arc-1, is an E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. arc-1 contains a modified C3HC3D-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 17542872 252 RPTCAICSTKYSKNCSTQTPRILDKCGHTLCEGCIQNILKHS-NQISCPICKSVT 305
Cdd:cd23124   1 ELECGICQQEYSADDPLLIPRILTECGHTICTNCAGTILGQSsGSIFCPFDRIVT 55

RING finger, HC subclass, found in tripartite motif-containing protein 32 (TRIM32) and similar proteins; TRIM32, also known as 72 kDa Tat-interacting protein, zinc finger protein HT2A, or BBS11, is an E3 ubiquitin-protein ligase that promotes degradation of several targets, including actin, PIASgamma, Abl interactor 2, dysbindin, X-linked inhibitor of apoptosis (XIAP), p73 transcription factor, thin filaments and Z-bands during fasting. It plays important roles in neuronal differentiation of neural progenitor cells, as well as in controlling cell fate in skeletal muscle progenitor cells. It reduces PI3K-Akt-FoxO signaling in muscle atrophy by promoting plakoglobin-PI3K dissociation. It also functions as a pluripotency-reprogramming roadblock that facilitates cellular transition towards differentiation by modulating the levels of Oct4 and cMyc. Moreover, TRIM32 is an intrinsic influenza A virus (IAV) restriction factor which senses and targets the polymerase basic protein 1 (PB1) for ubiquitination and protein degradation. It also plays a significant role in mediating the biological activity of the HIV-1 Tat protein in vivo, binds specifically to the activation domain of HIV-1 Tat, and can also interact with the HIV-2 and EIAV Tat proteins in vivo. Furthermore, TRIM32 regulates myoblast proliferation by controlling turnover of NDRG2 (N-myc downstream-regulated gene). It negatively regulates tumor suppressor p53 to promote tumorigenesis. It also facilitates degradation of MYCN on spindle poles and induces asymmetric cell division in human neuroblastoma cells. In addition, TRIM32 plays important roles in regulation of hyperactivities and positively regulates the development of anxiety and depression disorders induced by chronic stress. It also plays a role in regeneration by affecting satellite cell cycle progression via modulation of the SUMO ligase PIASy (PIAS4). Defects in TRIM32 leads to limb-girdle muscular dystrophy type 2H (LGMD2H), sarcotubular myopathies (STM) and Bardet-Biedl syndrome. TRIM32 belongs to the C-VII subclass of the TRIM (tripartite motif)-NHL family that is defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as a NHL (named after proteins NCL-1, HT2A and Lin-41 that contain repeats folded into a six-bladed beta propeller) repeat domain positioned C-terminal to the RBCC domain. The NHL domain mediates the interaction with Argonaute proteins and consequently allows TRIM32 to modulate the activity of certain miRNAs.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 17542872 253 PTCAICSTKYskNCSTQTPRILdKCGHTLCEGCIQNILKHS--NQISCPICKSV 304
Cdd:cd16587   1 LECPICLESF--DEGQLRPKLL-HCGHTICEQCLEKLLASLsiNGVRCPFCRKV 51

RING finger, HC subclass, found in RING finger protein RNF183, RNF223, RNF225 and similar proteins; RNF183 is an E3 ubiquitin-protein ligase that is upregulated during intestinal inflammation and is negatively regulated by miR-7. It promotes intestinal inflammation by increasing the ubiquitination and degradation of inhibitor of kappa B, thereby resulting in secondary activation of the Nuclear factor-kappaB (NF-kB) pathway. The interaction between RNF183-mediated ubiquitination and miRNA may be an important novel epigenetic mechanism in the pathogenesis of inflammatory bowel disease (IBD). The biological function of RNF223 and RNF225 remains unclear. Members of this family contain an N-terminal C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 17542872 253 PTCAICSTKYskNCSTQTPRILDkCGHTLCEGCI----QNILKHSNQISCPICKSVTVI 307
Cdd:cd16556   1 LECSICFSSY--DNTFKTPKLLD-CGHTFCLECLarlsLASPPQAERVPCPLCRQPTVL 56

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 17542872   255 CAICSTKYsKNCSTQTPrildkCGHTLCEGCIQNILKHSNQiSCPIC 301
Cdd:pfam00097   1 CPICLEEP-KDPVTLLP-----CGHLFCSKCIRSWLESGNV-TCPLC 40

RING finger, HC subclass, found in tripartite motif-containing protein TRIM2, TRIM3, and similar proteins; TRIM2, also known as RING finger protein 86 (RNF86), is an E3 ubiquitin-protein ligase that ubiquitinates the neurofilament light chain, a component of the intermediate filament in axons. Loss of function of TRIM2 results in early-onset axonal neuropathy. TRIM3, also known as brain-expressed RING finger protein (BERP), RING finger protein 97 (RNF97), or RING finger protein 22 (RNF22), is an E3 ubiquitin-protein ligase involved in the pathogenesis of various cancers. It also plays an important role in the central nervous system (CNS). In addition, TRIM3 may be involved in vesicular trafficking via its association with the cytoskeleton-associated-recycling or transport (CART) complex that is necessary for efficient transferrin receptor recycling, but not for epidermal growth factor receptor (EGFR) degradation. Both TRIM2 and TRIM3 belong to the C-VII subclass of the TRIM (tripartite motif)-NHL family that is defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as a NHL (named after proteins NCL-1, HT2A and Lin-41 that contain repeats folded into a six-bladed beta propeller) repeat domain positioned C-terminal to the RBCC domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 17542872 255 CAICSTKYskncstQTPRILdKCGHTLCEGCIQN-ILKHSNQISCPICK 302
Cdd:cd16586   4 CGICLERY------KNPKVL-PCLHTFCERCLQNyIPAESLSLSCPVCR 45

HC subclass of RING (RING-HC) finger and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle, and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 17542872 254 TCAICSTKYSkncstqtPRILDKCGHTLCEGCIQNILKHSNqISCPIC 301
Cdd:cd16449   2 ECPICLERLK-------DPVLLPCGHVFCRECIRRLLESGS-IKCPIC 41

zinc-RING finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 17542872   255 CAICSTKYSKNcstqTPRILDKCGHTLCEGCIQNILKhsnQISCPICKS 303
Cdd:pfam14634   2 CNKCFKELSKT----RPFYLTSCGHIFCEECLTRLLQ---ERQCPICKK 43

RING finger, HC subclass, found in RING finger protein MAT1; MAT1, also known as CDK-activating kinase assembly factor MAT1, CDK7/cyclin-H assembly factor, cyclin-G1-interacting protein, menage a trois, RING finger protein 66 (RNF66), p35, or p36, is involved in cell cycle control and in RNA transcription by RNA polymerase II. It associates primarily with the catalytic subunit cyclin-dependent kinase 7 (CDK7) and the regulatory subunit cyclin H to form the CDK-activating kinase (CAK) complex that can further associate with the core-TFIIH to form the transcription factor IIH (TFIIH) basal transcription/DNA repair factor, which activates RNA polymerase II by serine phosphorylation of the repetitive C-terminal domain (CTD) of its large subunit (POLR2A), allowing its escape from the promoter, and elongation of the transcripts. MAT1 contains an N-terminal C3HC4-type RING-HC finger, a central coiled coil domain, and a C-terminal domain rich in hydrophobic residues.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 17542872 254 TCAICSTKYSKNCSTQTprILDKCGHTLCEGCIqNILKHSNQISCPICK 302
Cdd:cd16517   2 YCPRCKTTKYRNPSLKL--MVNVCGHTLCESCV-DLLFVRGSGPCPECG 47

RING finger, HC subclass, found in yeast Bre1 and its homologs from eukaryotes; Bre1 is an E3 ubiquitin-protein ligase that catalyzes monoubiquitination of histone H2B in concert with the E2 ubiquitin-conjugating enzyme, Rad6. The Rad6-Bre1-mediated histone H2B ubiquitylation modulates the formation of double-strand breaks (DSBs) during meiosis in yeast. it is also required, indirectly, for the methylation of histone 3 on lysine 4 (H3K4) and 79. RNF20, also known as BRE1A and RNF40, also known as BRE1B, are the mammalian homologs of Bre1. They work together to form a heterodimeric Bre1 complex that facilitate the K120 monoubiquitination of histone H2B (H2Bub1), a DNA damage-induced histone modification that is crucial for recruitment of the chromatin remodeler SNF2h to DNA double-strand break (DSB) damage sites. Moreover, the Bre1 complex acts as a tumor suppressor, augmenting expression of select tumor suppressor genes and suppressing select oncogenes. Deficiency in the mammalian histone H2B ubiquitin ligase Bre1 leads to replication stress and chromosomal instability. All subfamily members contain a C3HC4-type RING-HC finger at its C-terminus.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 17542872 254 TCAICSTKYsKNCstqtprILDKCGHTLCEGCIQNILKhSNQISCPICK 302
Cdd:cd16499   8 KCSVCNDRF-KDV------IITKCGHVFCNECVQKRLE-TRQRKCPGCG 48

RING finger, HC subclass, found in tripartite motif-containing protein 2 (TRIM2); TRIM2, also known as RING finger protein 86 (RNF86), is an E3 ubiquitin-protein ligase that ubiquitinates the neurofilament light chain, a component of the intermediate filament in axons. Loss of function of TRIM2 results in early-onset axonal neuropathy. TRIM2 also plays a role in mediating the p42/p44 MAPK-dependent ubiquitination of the cell death-promoting protein Bcl-2-interacting mediator of cell death (Bim) in rapid ischemic tolerance. TRIM2 belongs to the C-VII subclass of the TRIM (tripartite motif)-NHL family that is defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as a NHL (named after proteins NCL-1, HT2A and Lin-41 that contain repeats folded into a six-bladed beta propeller) repeat domain positioned C-terminal to the RBCC domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 17542872 255 CAICSTKYskncstQTPRILdKCGHTLCEGCIQN-ILKHSNQISCPICK 302
Cdd:cd16767   9 CSICLDRY------KNPKVL-PCLHTFCERCLQNyIPAHSLTLSCPVCR 50

RING finger, HC subclass, found in tripartite motif-containing protein 3 (TRIM3); TRIM3, also known as brain-expressed RING finger protein (BERP), RING finger protein 97 (RNF97), or RING finger protein 22 (RNF22), is an E3 ubiquitin-protein ligase involved in the pathogenesis of various cancers. It functions as a tumor suppressor that regulates asymmetric cell division in glioblastoma. It binds to the cdk inhibitor p21(WAF1/CIP1) and regulates its availability that promotes cyclin D1-cdk4 nuclear accumulation. Moreover, TRIM3 plays an important role in the central nervous system (CNS). It is encoded by the gene BERP (brain-expressed RING finger protein), a unique p53-regulated gene that modulates seizure susceptibility and GABAAR cell surface expression. Furthermore, TRIM3 mediates activity-dependent turnover of postsynaptic density (PSD) scaffold proteins GKAP/SAPAP1 and is a negative regulator of dendritic spine morphology. In addition, TRIM3 may be involved in vesicular trafficking via its association with the cytoskeleton-associated-recycling or transport (CART) complex that is necessary for efficient transferrin receptor recycling, but not for epidermal growth factor receptor (EGFR) degradation. It also regulates the motility of the kinesin superfamily protein KIF21B. TRIM3 belongs to the C-VII subclass of the TRIM (tripartite motif)-NHL family that is defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as a NHL (named after proteins NCL-1, HT2A and Lin-41 that contain repeats folded into a six-bladed beta propeller) repeat domain positioned C-terminal to the RBCC domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*....
gi 17542872 255 CAICSTKYskncstQTPRILdKCGHTLCEGCIQN-ILKHSNQISCPICK 302
Cdd:cd16768   7 CSICLDRY------HNPKVL-PCLHTFCERCLQNyIPPQSLTLSCPVCR 48

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

                        10        20        30
                ....*....|....*....|....*....|.
gi 17542872 276 KCGHTLCEGCIQNILKHSNQ-ISCPICKSVT 305
Cdd:cd16498  33 KCDHQFCRFCILKLLQKKKKpAPCPLCKKSV 63

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

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                ....*....|....*....|....*....|....*....|....*....|
gi 17542872 255 CAICSTKYSKncstqtPRILDKCGHTLCEGCIQNILKHsnQISCPICKSV 304
Cdd:cd16712   6 CPICMDRISN------KKVLPKCKHVFCAACIDKAMKY--KPVCPVCGTI 47

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 17542872 253 PTCAICSTKYSKNCStqtprILDKCGHTLCEGCIQNILKHSNqiSCPICK 302
Cdd:cd16574   2 SSCPICLDRFENEKA-----FLDGCFHAFCFTCILEWSKVKN--ECPLCK 44

RING finger, HC subclass, found in SH3 domain-containing RING finger protein 2 (SH3RF2) and similar proteins; SH3RF2, also known as heart protein phosphatase 1-binding protein (HEPP1), plenty of SH3s (POSH)-eliminating RING protein (POSHER), protein phosphatase 1 regulatory subunit 39, or RING finger protein 158 (RNF158), is a putative E3 ubiquitin-protein ligase that acts as an anti-apoptotic regulator for the c-Jun N-terminal kinase (JNK) pathway by binding to and promoting the proteasomal degradation of SH3RF1 (or POSH), a scaffold protein that is required for pro-apoptotic JNK activation. It may also play a role in cardiac functions together with protein phosphatase 1. SH3RF2 contains an N-terminal C3HC4-type RING-HC finger responsible for the E3 ligase activity and four Src Homology 3 (SH3) domains, which are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs.

                        10        20
                ....*....|....*....|....*..
gi 17542872 277 CGHTLCEGCIQNILKHSNQISCPICKS 303
Cdd:cd16749  19 CQHTFCKPCLQRIFKARKELRCPECRT 45

RING-type zinc-finger; This zinc-finger is a typical RING-type of plant ubiquitin ligases.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 17542872   255 CAICSTKYSkncstqTPRIldKCGHTLCEGCI-QNILKHSNQISCP 299
Cdd:pfam13445   1 CPICLELFT------DPVL--PCGHTFCRECLeEMSQKKGGKFKCP 38

RING finger, HC subclass, found in RING finger protein 152 (RNF152) and similar proteins; RNF152 is a lysosome-anchored E3 ubiquitin-protein ligase involved in apoptosis. It is polyubiquitinated through K48 linkage. It negatively regulates the activation of the mTORC1 pathway by targeting RagA GTPase for K63-linked ubiquitination. It interacts with and ubiquitinates RagA in an amino-acid-sensitive manner. The ubiquitination of RagA recruits its inhibitor GATOR1, a GAP complex for Rag GTPases, to the Rag complex, thereby inactivating mTORC1 signaling. RNF152 contains an N-terminal C3HC4-type RING-HC finger and a C-terminal transmembrane domain, both of which are responsible for its E3 ligase activity.

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                ....*....|....*....|....*....|....*....|....*...
gi 17542872 255 CAICSTKYSKNcstQTPRILDkCGHTLCEGCIQNILKHSNQISCPICK 302
Cdd:cd16548   3 CQICFNYYSPR---RRPKLLD-CKHTCCSVCLQQMRTSQKDLRCPWCR 46

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

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 17542872 254 TCAICSTKYSKNCSTQTPRILDK------CGHTLCEGCIQNILKHsnQISCPICKSVTVINE 309
Cdd:COG5243 289 TCTICMDEMFHPDHEPLPRGLDMtpkrlpCGHILHLHCLKNWLER--QQTCPICRRPVIFDQ 348

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

                        10        20
                ....*....|....*....|....*...
gi 17542872 277 CGHTLCEGCIQNILKHSNQisCPICKSV 304
Cdd:cd16514  19 CGHTFCRACLERCLDHSPK--CPLCRTS 44