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 157819757    20 CKICYNRYnlkQRKPKVLECCHRVCAKCLYKIIDfgdspQGVIVCPFC 67
Cdd:smart00184   1 CPICLEEY---LKDPVILPCGHTFCRSCIRKWLE-----SGNNTCPIC 40

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.

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                 ....*....|....*....|....*....|....*....|....*....|.
gi 157819757  18 LECKICYNRYNLKQRKPKVLECCHRVCAKCLYKIIDFgdSPQGVIVCPFCR 68
Cdd:cd16587    1 LECPICLESFDEGQLRPKLLHCGHTICEQCLEKLLAS--LSINGVRCPFCR 49

RING finger, HC subclass, found in RING finger protein 186 (RNF186) and similar proteins; RNF186 is an E3 ubiquitin-protein ligase with an N-terminal C3HC4-type RING-HC finger and two putative C-terminal transmembrane domains which enable it to localize in a certain organelle. It regulates RING-dependent self-ubiquitination, as well as endoplasmic reticulum (ER) stress-mediated apoptosis through interaction with the Bcl-2 family protein BNip1.

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                 ....*....|....*....|....*....|....*....|....*....|..
gi 157819757  17 ELECKICYNRYNLKQRKPKVLECCHRVCAKCLYKIIDFGDSPQGViVCPFCR 68
Cdd:cd16557    1 DLECLVCRNPYSCFVRKPKLLACQHAFCAICLKLILCEQDGTWSV-TCPLCR 51

RING finger, HC subclass, found in RING finger protein RNF224 and similar proteins; RNF224 is uncharacterized C3HC4-type RING-HC finger-containing proteins. It may function as an E3 ubiquitin-protein ligase.

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                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 157819757  18 LECKICYNRYNLKQRKPKVLECCHRVCAKCLyKIIDFGDSPQGVIVCPFCRFETCLP 74
Cdd:cd16565    1 LDCIICYSAYDLSTRLPRRLYCGHTFCQACL-KRLDTVINEQRWIPCPQCRQNTPTP 56

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.

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                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 157819757  17 ELECKICYNRY--NLKQRKPKVL-ECCHRVCAKCLYKIIdfGDSPqGVIVCPFCRFET 71
Cdd:cd23124    1 ELECGICQQEYsaDDPLLIPRILtECGHTICTNCAGTIL--GQSS-GSIFCPFDRIVT 55

RING finger, HC subclass, found in Arabidopsis thaliana protein KEEP ON GOING (KEG) and similar proteins; KEG, also called RING-type E3 ubiquitin transferase KEG, is a RING E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. It is essential for Arabidopsis growth and development. It acts as a negative regulator of abscisic acid signaling. It is required for ABSCISIC ACID-INSENSITIVE5 (ABI5) degradation, by mediating its ubiquitination. Together with EDR1, KEG may regulate endocytic trafficking and/or the formation of signaling complexes on trans-Golgi network (TGN)/ early endosome (EE) vesicles during stress responses. KEG is a multidomain protein that includes a C3HC4-type RING-HC finger, a kinase domain, ankyrin repeats, and 12 HERC2-like (for HECT and RCC1-like) repeats.

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                 ....*....|....*....|....*....|....*....|....*....|
gi 157819757  19 ECKICYNRYNLKQRKPKVLECCHRVCAKCLYKIidFGDSPQGVIVCPFCR 68
Cdd:cd23140    3 ECSVCSEGYNEDERVPLLLQCGHTFCKDCLSQM--FIRCTDLTLKCPRCR 50

RING finger, HC subclass, found in tripartite motif-containing protein 9 (TRIM9) and similar proteins; TRIM9, 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 the neurodegenerative disorders through its ligase activity. It interacts with the WD repeat region of beta-transducin repeat-containing protein (beta-TrCP) through its N-terminal degron motif depending on the phosphorylation status, and thus negatively regulates nuclear factor-kappaB (NF-kappaB) activation in the NF-kappaB pro-inflammatory signaling pathway. Moreover, TRIM9 acts as a critical catalytic link between Netrin-1 and the exocytic soluble NSF attachment receptor protein (SNARE) machinery in murine cortical neurons. It promotes SNARE-mediated vesicle fusion and axon branching in a Netrin-dependent manner. TRIM9 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.

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                 ....*....|....*....|....*....|....*....|....*....|....*
gi 157819757  16 DELECKICYNRYnlkqRKPKVLECCHRVCAKCLYKII---DFGDSPQGVIVCPFC 67
Cdd:cd16755    2 EELKCPVCGSFY----REPIILPCSHNLCLACARNILvqtPEAESPQSCLTCPQC 52

RING finger, HC subclass, found in RING finger protein 222 (RNF222) and similar proteins; RNF222 is an uncharacterized C3HC4-type RING-HC finger-containing protein. It may function as an E3 ubiquitin-protein ligase.

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                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 157819757  19 ECKICYNRYnlkQRKPKVLECCHRVCAKCLYKIidfgdSPQGVIVCPFCRFETCLP 74
Cdd:cd16564    2 ECPVCYEDF---DDAPRILSCGHSFCEDCLVKQ-----LVSMTISCPICRRVTFIS 49

Modified RING finger, HC subclass (C3HC3D-type), found in Roquin-2; Roquin-2, also known as membrane-associated nucleic acid-binding protein (MNAB), RING finger and CCCH-type zinc finger domain-containing protein 2 (RC3H2), or RING finger protein 164 (RNF164), is an E3 ubiquitin ligase that is localized to the cytoplasm and upon stress, is concentrated in stress granules. It is required for reactive oxygen species (ROS)-induced ubiquitination and degradation of apoptosis signal-regulating kinase 1 (ASK1, also known as MAP3K5). Roquin-2 interacts with the 3'UTR of tumor necrosis factor receptor superfamily member 4 (TNFRSF4) and tumor-necrosis factor-alpha (TNFalpha), and modulates immune responses. Moreover, Roquin-2 shares functions with its paralog Roquin-1 in the repression of mRNAs controlling T follicular helper cells and systemic inflammation. Roquin-2 contains an N-terminal modified C3HC3D-type RING-HC finger with a potential E3 ubiquitin-ligase function, a highly conserved ROQ domain required for RNA binding and localization to stress granules, a coiled-coil (CC1), and a CCCH-type zinc finger that is involved in RNA recognition.

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                 ....*....|....*....|....*....|....*....
gi 157819757  13 QVSDELECKICYNRYNLKQRKPKVLECCHRVCAKCLYKI 51
Cdd:cd16782    1 QWTEFLSCPICYNEFDENVHKPISLGCSHTVCKTCLNKL 39

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.

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                 ....*....|....*....|....*....|....*....|....*....|
gi 157819757  18 LECKICYNRYnlkqRKPKVLECCHRVCAKCLYKIIDFGDspqgvIVCPFC 67
Cdd:cd16449    1 LECPICLERL----KDPVLLPCGHVFCRECIRRLLESGS-----IKCPIC 41

RING finger, HC subclass, found in Caenorhabditis elegans RING finger protein NHL-1 and similar proteins; NHL-1 functions as an E3 ubiquitin-protein ligase in the presence of both UBC-13 and UBC-1 within the ubiquitin pathway of Caenorhabditis elegans. It acts in chemosensory neurons to promote stress resistance in distal tissues by the transcription factor DAF-16 activation but is dispensable for the activation of heat shock factor 1 (HSF-1). NHL-1 belongs to the TRIM (tripartite motif)-NHL family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil domain, as well as an 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.

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                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 157819757  13 QVSDELECKICYNRYnlkqRKPKVLECCHRVCAK-CLYKIIDFGDSpqgVIVCPFCRFE 70
Cdd:cd16524    1 QIEQLLTCPICLDRY----RRPKLLPCQHTFCLSpCLEGLVDYVTR---KLKCPECRAE 52