RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270   23 SRDVRQFHDLITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECKASGGKEINELNLKSDDTLRSLIYKLVPG 102
Cdd:cd16737     1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                          90
                  ....*....|....*
gi 281363270  103 LYQRECKELADFKEQ 117
Cdd:cd16737    81 LRERELQREAEFWEK 95

RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270   23 SRDVRQFHDLITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECKASGGKEINELNLKSDDTLRSLIYKLVPG 102
Cdd:cd16737     1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                          90
                  ....*....|....*
gi 281363270  103 LYQRECKELADFKEQ 117
Cdd:cd16737    81 LRERELQREAEFWEK 95

RAWUL domain RING finger- and WD40-associated ubiquitin-like; The RAWUL domain is found at the C-terminus of poly-comb group RING finger proteins. It is a ubiquitin-like domain. RAWUL binds directly to PUFD, a domain on BCOR proteins (BCL6 corepressor). BCOR has emerged as an important player in development and health.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 281363270   162 YLQCAAGLPVELLKRFLCSKYNIETDNgLVEVEVTYKDEVLPTNFTLmDVAYCYNWSRESPMAFCYR 228
Cdd:pfam16207    2 YLKCPANATVDHLKKYLAMKLGLELQN-EYIVEILYNGEPLPDSYTL-DVAYIKYWKRNAPLELYYR 66

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                            10        20        30        40
                    ....*....|....*....|....*....|....*....|
gi 281363270     35 CRLCRGYMIDPTTVDYCYHTYCRSCILKHLL-RAVYCPEC 73
Cdd:smart00184    1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLEsGNNTCPIC 40

RING finger found in polycomb group RING finger protein 5 (PCGF5) and similar proteins; PCGF5, also known as RING finger protein 159 (RNF159), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a Polycomb repressive complex 1 (PRC1). Like other PCGF homologs, PCGF5 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. PCGF5 contains a C3HC4-type RING-HC finger.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270   23 SRDVRQFHDLITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECKASGGKEINELNLKSDDTLRSLIYKLVPG 102
Cdd:cd16737     1 KHLVRDFNPYITCRICKGYLIKPTTVTECLHTFCKSCIVQHFEDSNDCPECGIQVHETNPLEMLRLDNTLEEIIFKLVPG 80

                          90
                  ....*....|....*
gi 281363270  103 LYQRECKELADFKEQ 117
Cdd:cd16737    81 LRERELQREAEFWEK 95

RAWUL domain RING finger- and WD40-associated ubiquitin-like; The RAWUL domain is found at the C-terminus of poly-comb group RING finger proteins. It is a ubiquitin-like domain. RAWUL binds directly to PUFD, a domain on BCOR proteins (BCL6 corepressor). BCOR has emerged as an important player in development and health.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 281363270   162 YLQCAAGLPVELLKRFLCSKYNIETDNgLVEVEVTYKDEVLPTNFTLmDVAYCYNWSRESPMAFCYR 228
Cdd:pfam16207    2 YLKCPANATVDHLKKYLAMKLGLELQN-EYIVEILYNGEPLPDSYTL-DVAYIKYWKRNAPLELYYR 66

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 281363270   33 ITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPEC 73
Cdd:cd16525     1 LTCSLCKGYLIDATTITECLHSFCKSCIVRHLETSKNCPVC 41

RING finger found in polycomb group RING finger protein 2 (PCGF2) and similar proteins; PCGF2, also known as DNA-binding protein Mel-18, RING finger protein 110 (RNF110), or zinc finger protein 144 (ZNF144), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR). It serves as the core component of a canonical Polycomb repressive complex 1 (PRC1), which is composed of a chromodomain-containing protein (CBX2, CBX4, CBX6, CBX7 or CBX8) and a Polyhomeotic protein (PHC1, PHC2, or PHC3). Like other PCGF homologs, PCGF2 associates with ring finger protein 2 (RNF2) to form a RNF2-PCGF heterodimer, which is catalytically competent as an E3 ubiquitin transferase and is the scaffold for the assembly of additional components. Moreover, PCGF2 uniquely regulates PRC1 to specify mesoderm cell fate in embryonic stem cells. It is required for PRC1 stability and maintenance of gene repression in embryonic stem cells (ESCs) and essential for ESC differentiation into early cardiac-mesoderm precursors. PCGF2 also plays a significant role in the angiogenic function of endothelial cells (ECs) by regulating endothelial gene expression. Furthermore, PCGF2 is a SUMO-dependent regulator of hormone receptors. It facilitates the deSUMOylation process by inhibiting PCGF4/BMI1-mediated ubiquitin-proteasomal degradation of SUMO1/sentrin-specific protease 1 (SENP1). It is also a novel negative regulator of breast cancer stem cells (CSCs) that inhibits the stem cell population and in vitro and in vivo self-renewal through the inactivation of Wnt-mediated Notch signaling. PCGF2 contains a C3HC4-type RING-HC finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 281363270   33 ITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECKASGGKEINELNLKSDDTLRSLIYK 98
Cdd:cd16734    15 LMCALCGGYFIDAATIVECLHSFCKTCIVRYLETNKYCPMCDVQVHKTRPLLSIRSDKTLQDIVYK 80

RING finger- and WD40-associated ubiquitin-like (RAWUL) domain found in polycomb group RING finger protein 4 (PCGF4); PCGF4, also termed polycomb complex protein BMI-1 (B cell-specific Moloney murine leukemia virus integration site 1), or RING finger protein 51 (RNF51), is one of six PcG RING finger (PCGF) homologs (PCGF1/NSPc1, PCGF2/Mel-18, PCGF3, PCGF4/BMI1, PCGF5, and PCGF6/MBLR) and serves as the core component of a canonical Polycomb repressive complex 1 (PRC1), which is composed of a chromodomain-containing protein (CBX2, CBX4, CBX6, CBX7 or CBX8) and a Polyhomeotic protein (PHC1, PHC2, or PHC3), and plays important roles in chromatin compaction and H2AK119 monoubiquitination. PCGF4 associates with the Runx1/CBFbeta transcription factor complex to silence target gene in a PRC2-independent manner. Moreover, PCGF4 is expressed in the hair cells and supporting cells. It can regulate cell survival by controlling mitochondrial function and reactive oxygen species (ROS) level in thymocytes and neurons, thus having an important role in the survival and sensitivity to ototoxic drug of auditory hair cells. Furthermore, PCGF4 controls memory CD4 T-cell survival through direct repression of Noxa gene in an Ink4a- and Arf-independent manner. It is required in neurons to suppress p53-induced apoptosis via regulating the antioxidant defensive response, and also involved in the tumorigenesis of various cancer types. PCGF4 contains a C3HC4-type RING-HC finger, and a RAWUL domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270  137 LISLSLEYHPAMLHQCGPG--------EVPPTIYLQCAAGLPVELLKRFLCSKYNIETDnglVEVEVTYKDEVLPTNFTL 208
Cdd:cd17165     1 IISLSIEFFDQNKLERKGNkdkekskeEVNDKRYLRCPAAMTVMHLRKFLRSKMDIPST---FQIDVMYEEEPLKDYYTL 77

                          90       100
                  ....*....|....*....|
gi 281363270  209 MDVAYCYNWSRESPMAFCYR 228
Cdd:cd17165    78 MDIAYIYTWRRNGPLPLKYR 97

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 281363270    35 CRLCRGYMIDPTTVDYCYHTYCRSCILKHLL-RAVYCPEC 73
Cdd:pfam00097    1 CPICLEEPKDPVTLLPCGHLFCSKCIRSWLEsGNVTCPLC 40

Variant RING finger, HC subclass (C4C4-type), found in retinoblastoma-binding protein 6 (RBBP6) and similar proteins; RBBP6, also known as proliferation potential-related protein, protein P2P-R, retinoblastoma-binding Q protein 1 (RBQ-1), or p53-associated cellular protein of testis (PACT), is a nuclear E3 ubiquitin-protein ligase involved in multiple processes, such as the control of gene expression, mitosis, cell differentiation, and cell apoptosis. It plays a role in both promoting and inhibiting apoptosis in many human cancers, including esophageal, lung, hepatocellular, and colon cancers, familial myeloproliferative neoplasms, as well as in human immunodeficiency virus-associated nephropathy (HIVAN). It functions as an Rb- and p53-binding protein that plays an important role in chaperone-mediated ubiquitination and possibly in protein quality control. It acts as a scaffold protein to promote the assembly of the p53/TP53-MDM2 complex, resulting in an increase of MDM2-mediated ubiquitination and degradation of p53/TP53, and leading to both apoptosis and cell growth. It is also a double-stranded RNA-binding protein that plays a role in mRNA processing by regulating the human polyadenylation machinery and modulating expression of mRNAs with AU-rich 3' untranslated regions (UTRs). Moreover, RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38 that negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Furthermore, RBBP6 is involved in tunicamycin-induced apoptosis by mediating protein kinase (PKR) activation. RBBP6 contains an N-terminal ubiquitin-like domain and a C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger. RBBP6 interacts with chaperones Hsp70 and Hsp40 through its N-terminal ubiquitin-like domain. It promotes the ubiquitination of p53 by Hdm2 in an E4-like manner through its RING finger. It also interacts directly with the pro-proliferative transcription factor Y-box-binding protein-1 (YB-1) via its RING finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270   34 TCRLCRGYMIDPTTVDYCYHTYCRSCILKHLL-RAVYCPECKASggkeinelnLKSDDTL 92
Cdd:cd16620     5 KCPICKDLMKDAVLTPCCGNSFCDECIRTALLeEDFTCPTCKEP---------DVSPDAL 55

RING finger, HC subclass, found in RING finger protein 39 (RNF39) and similar proteins; RNF39, also called protein HZFw, may play a role in prolonged long term-potentiation (LTP) maintenance. It is involved in the etiology of Behcet's disease (BD). It may also be involved in HIV-1 replication. RNF39 acts as an E3 ubiquitin ligase that inhibits retinoic acid-inducible gene-I (RIG-I)-like receptor (RLR) pathways by mediating K48-linked ubiquitination and proteasomal degradation of DDX3X (DEAD-box RNA helicase 3, X-linked). RNF39 contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 281363270   31 DLITCRLCRGYMIDPTTVDyCYHTYCRSCILKHL---------LRAVYCPECK 74
Cdd:cd16592     3 EETTCPICLGYFKDPVILD-CEHSFCRACIARHWgqeamegngAEGVFCPQCG 54

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 281363270   29 FHDLITCRLCRGYMIDPTTVDyCYHTYCRSCILK---HLLRAVYCPECKA 75
Cdd:cd16594     2 LQEELTCPICLDYFTDPVTLD-CGHSFCRACIARcweEPETSASCPQCRE 50

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 281363270   34 TCRLCRGYMIDPTTVDyCYHTYCRSCILKHL-LRAVYCPEC 73
Cdd:cd16449     2 ECPICLERLKDPVLLP-CGHVFCRECIRRLLeSGSIKCPIC 41

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 281363270   33 ITCRLCRGYMIDPTTVDyCYHTYCRSCILKHLLR-----AVYCPECKASGGKE 80
Cdd:cd16598     5 VTCSICLDYLRDPVTID-CGHNFCRSCITDYCPIsggheRPVCPLCRKPFKKE 56

RING finger, HC subclass, found in tripartite motif-containing protein 38 (TRIM38) and similar proteins; TRIM38, also known as RING finger protein 15 (RNF15) or zinc finger protein RoRet, is an E3 ubiquitin-protein ligase that promotes K63- and K48-linked ubiquitination of cellular proteins and also catalyzes self-ubiquitination. It negatively regulates Tumor necrosis factor alpha (TNF-alpha)- and interleukin-1beta-triggered Nuclear factor-kappaB (NF-kappaB) activation by mediating lysosomal-dependent degradation of transforming growth factor beta (TGFbeta)-activated kinase 1 (TAK1)-binding protein (TAB)2/3, two critical components of the TAK1 kinase complex. It also inhibits TLR3/4-mediated activation of NF-kappaB and interferon regulatory factor 3 (IRF3) by mediating ubiquitin-proteasomal degradation of TNF receptor-associated factor 6 (Traf6) and NAK-associated protein 1 (Nap1), respectively. Moreover, TRIM38 negatively regulates TLR3-mediated interferon beta (IFN-beta) signaling by targeting ubiquitin-proteasomal degradation of TIR domain-containing adaptor inducing IFN-beta (TRIF). It functions as a valid target for autoantibodies in primary Sjogren's Syndrome. TRIM38 belongs the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 281363270   34 TCRLCRGYMIDPTTVDyCYHTYCRSCI---------LKHLLRAVYCPECKA 75
Cdd:cd16600     7 TCSICLQLMTEPVSIN-CGHSYCKRCIvsflenqsqLEPGLETFSCPQCRA 56

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 281363270   31 DLITCRLCRGYMIDPTTVDyCYHTYCRSCILKHL--LRAVYCPECKAS 76
Cdd:cd16568     3 ETQECIICHEYLYEPMVTT-CGHTYCYTCLNTWFksNRSLSCPDCRTK 49

RING finger, HC subclass, found in RING finger protein 151 (RNF151) and similar proteins; RNF151 is a testis-specific RING finger protein that interacts with dysbindin, a synaptic and microtubular protein that binds brain snapin, a SNARE-binding protein that mediates intracellular membrane fusion in both neuronal and non-neuronal cells. Thus, it may be involved in acrosome formation of spermatids by interacting with multiple proteins participating in membrane biogenesis and microtubule organization. RNF151 contains a C3HC4-type RING finger domain, a putative nuclear localization signal (NLS), and a TNF receptor associated factor (TRAF)-type zinc finger domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 281363270   31 DLItCRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAVYCPECKAS 76
Cdd:cd16547     3 DLI-CSICHGVLRCPVRLS-CSHIFCKKCILQWLKRQETCPCCRKE 46

RING finger, HC subclass, found in tripartite motif-containing protein 62 (TRIM62) and similar proteins; TRIM62, also known as Ductal Epithelium Associated Ring Chromosome 1 (DEAR1), is a cytoplasmic E3 ubiquitin-protein ligase that was identified as a dominant regulator of acinar morphogenesis in the mammary gland. It is implicated in the inflammatory response of immune cells by regulating the Toll-like receptor 4 (TLR4) signaling pathway, leading to increased activity of the activator protein 1 (AP-1) transcription factor in primary macrophages. It is also involved in muscular protein homeostasis, especially during inflammation-induced atrophy, and may play a role in the pathogenesis of ICU-acquired weakness (ICUAW) by activating and maintaining inflammation in myocytes. Moreover, TRIM62 facilitates K27-linked poly-ubiquitination of CARD9 and also regulates CARD9-mediated anti-fungal immunity and intestinal inflammation. It also functions as a chromosome 1p35 tumor suppressor and negatively regulates transforming growth factor beta (TGFbeta)-driven epithelial-mesenchymal transition (EMT) by binding to and promoting the ubiquitination of SMAD3, a major effector of TGFbeta-mediated EMT. TRIM62 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 281363270   31 DLITCRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAVY--CPECKA 75
Cdd:cd16608     5 DELLCSICLSIYQDPVSLG-CEHYFCRQCITEHWSRSEHrdCPECRR 50

Zinc finger, C3HC4 type (RING finger);

                           10        20        30
                   ....*....|....*....|....*....|....*....
gi 281363270    35 CRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPEC 73
Cdd:pfam13923    2 CPICMDMLKDPSTTTPCGHVFCQDCILRALEASNECPLC 40

RING finger, HC subclass, found in Mus musculus tripartite motif-containing protein 43 (TRIM43) and similar propteins; This subfamily includes TRIM43A, TRIM43B and TRIM43C, which are expressed specifically in mouse preimplantation embryos. They contain a typical C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 281363270   33 ITCRLCRGYMIDPTTVDyCYHTYCRSCIL---KHLLRAVYCPECK 74
Cdd:cd23133     4 LTCSICQGIFMNPVYLR-CGHKFCEACLLlfqEDIKFPAYCPMCR 47

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Deltex3 (DTX3), Deltex-3-like (DTX3L) and similar proteins; This subfamily contains Deltex3 (DTX3) and Deltex-3-like (DTX3L), both of which are E3 ubiquitin-protein ligases belonging to the Deltex (DTX) family. DTX3, also known as RING finger protein 154 (RNF154), has a biological function that remains unclear. DTX3L, also known as B-lymphoma- and BAL-associated protein (BBAP) or Rhysin-2 (Rhysin2), regulates endosomal sorting of the G protein-coupled receptor CXCR4 from endosomes to lysosomes. It also regulates subcellular localization of its partner protein, B aggressive lymphoma (BAL), by a dynamic nucleocytoplasmic trafficking mechanism. In contrast to other DTXs, both DTX3 and DTX3L contain a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain. DTX3L can associate with DTX1 through its unique N termini and further enhance self-ubiquitination.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 281363270   34 TCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECK 74
Cdd:cd16506     2 TCPICLDEIQNKKTLEKCKHSFCEDCIDRALQVKPVCPVCG 42

Modified RING finger, HC subclass (C3HC3D-type), found in tumor necrosis factor (TNF) receptor-associated factor 4 (TRAF4) and similar proteins; TRAF4, also known as cysteine-rich domain associated with RING and Traf domains protein 1, metastatic lymph node gene 62 protein (MLN 62), or RING finger protein 83 (RNF83), is a member of the TRAF protein family, which mainly function in the immune system, where they mediate signaling through tumor necrosis factor receptors (TNFRs) and interleukin-1/Toll-like receptors (IL-1/TLRs). It also plays a critical role in nervous system, as well as in carcinogenesis. TRAF4 promotes the growth and invasion of colon cancer through the Wnt/beta-catenin pathway. It contributes to the TNFalpha-induced activation of the 70 kDa ribosomal protein S6 kinase (p70s6k) signaling pathway, and activation of transforming growth factor beta (TGF-beta)-induced SMAD-dependent signaling and non-SMAD signaling in breast cancer. It also enhances osteosarcoma cell proliferation and invasion by the Akt signaling pathway. Moreover, TRAF4 is a novel phosphoinositide-binding protein modulating tight junctions and favoring cell migration. TRAF4 contains an N-terminal domain with a modified C3HC3D-type RING-HC finger and several zinc fingers, and a C-terminal TRAF domain that comprises a coiled coil domain and a conserved TRAF-C domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 281363270   34 TCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVY-CPE 72
Cdd:cd16641     3 LCPLCRLPMREPVQISTCGHRFCDTCLQEFLSEGVFkCPE 42

zinc finger of C3HC4-type, RING; This is a family of primate-specific Ret finger protein-like (RFPL) zinc-fingers of the C3HC4 type. Ret finger protein-like proteins are primate-specific target genes of Pax6, a key transcription factor for pancreas, eye and neocortex development. This domain is likely to be DNA-binding. This zinc-finger domain together with the RDM domain, pfam11002, forms a large zinc-finger structure of the RING/U-Box superfamily. RING-containing proteins are known to exert an E3 ubiquitin protein ligase activity with the zinc-finger structure being mandatory for binding to the E2 ubiquitin-conjugating enzyme.

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|...
gi 281363270    35 CRLCRGYMIDPTTVDyCYHTYCRSCI--LKHLLRAVY--CPEC 73
Cdd:pfam15227    1 CPICLDYLEKPVSIE-CGHSFCLSCInsLQKEPDGESllCPQC 42

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 281363270   35 CRLCRGYMIDPTTVDyCYHTYCRSCILKhlLRAVYCPECKAS 76
Cdd:cd16602     6 CAICLDYFKDPVSIG-CGHNFCRVCVTQ--LWGFTCPQCRKS 44

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 281363270   35 CRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAVYCPECKAS 76
Cdd:cd16514     4 CSLCLRLLYEPVTTP-CGHTFCRACLERCLDHSPKCPLCRTS 44

RING finger, HC subclass, found in RING finger protein 220 (RNF220) and similar proteins; RNF220 is an E3 ubiquitin-protein ligase that promotes the ubiquitination and proteasomal degradation of Sin3B, a scaffold protein of the Sin3/HDAC (histone deacetylase) corepressor complex. It can also bind E2 and mediate auto-ubiquitination of itself. Moreover, RNF220 specifically interacts with beta-catenin, and enhances canonical Wnt signaling through ubiquitin-specific protease 7 (USP7)-mediated deubiquitination and stabilization of beta-catenin, which is independent of its E3 ligase activity. RNF220 contains a characteristic C3HC4-type RING-HC finger at its C-terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 281363270   35 CRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVYCPECK 74
Cdd:cd16563     3 CLICMDSYTMPLVSIQCWHVHCEECWLRTLGAKKLCPQCN 42

RING finger, HC subclass, found in really interesting new gene proteins RING1, RING2 and similar proteins; RING1, also known as polycomb complex protein RING1, RING finger protein 1 (RNF1), or RING finger protein 1A (RING1A), is a transcriptional repressor that is associated with the Polycomb group (PcG) protein complex involved in stable repression of gene activity. RING2, also known as huntingtin-interacting protein 2-interacting protein 3, HIP2-interacting protein 3, protein DinG, RING finger protein 1B (RING1B), RING finger protein 2 (RNF2), or RING finger protein BAP-1, is an E3 ubiquitin-protein ligase that interacts with both nucleosomal DNA and an acidic patch on histone H4 to achieve the specific monoubiquitination of K119 on histone H2A (H2AK119ub), thereby playing a central role in histone code and gene regulation. Both RING1 and RING2 are core components of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. RING2 acts as the main E3 ubiquitin ligase on histone H2A of the PRC1 complex, while RING1 may rather act as a modulator of RNF2/RING2 activity. Members of this family contain a C3HC4-type RING-HC finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 281363270   33 ITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAVY-CPECKASGGkeiNELNLKSDDTLRSLIYKL 99
Cdd:cd16531     2 LMCPICLGIIKNTMTVKECLHRFCAECIEKALRLGNKeCPTCRKHLP---SRRSLRPDPNFDALISKI 66

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 281363270    8 NTMESNAAMDAASPASRDVRQFHDLITCRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAVYCPECKA----------SG 77
Cdd:COG5432     1 NELDATDPSDWNQTKIPSLKGLDSMLRCRICDCRISIPCETT-CGHTFCSLCIRRHLGTQPFCPVCREdpcesrlrgsSG 79

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....
gi 281363270   78 GKEINELNLKSDDTLRSLIYKL----VPGLYQRECKELADFKEQHDLVDEQTTD 127
Cdd:COG5432    80 SREINESHARNRDLLRKVLESLcrlpRPIKEERPCRWETVIAQDSASGDEEWED 133

RING finger, HC subclass, found in BRCA1-associated RING domain protein 1 (BARD-1) and similar proteins; BARD-1 is a critical factor in BRCA1-mediated tumor suppression and may also serve as a target for tumorigenic lesions in some human cancers. It associates with BRCA1 (breast cancer-1) to form a heterodimeric BRCA1/BARD1 complex that is responsible for maintaining genomic stability through nuclear functions involving DNA damage signaling and repair, transcriptional regulation, and cell cycle control. The BRCA1/BARD1 complex catalyzes autoubiquitination of BRCA1 and trans ubiquitination of other protein substrates. Its E3 ligase activity is dramatically reduced in the presence of UBX domain protein 1 (UBXN1). BARD-1 contains an C3HC4-type RING-HC finger that binds BRCA1 at its N-terminus and three tandem ankyrin repeats and tandem BRCT repeat domains at its C-terminus. The BRCT repeats bind CstF-50 (cleavage stimulation factor) to modulate mRNA processing and RNAP II stability in response to DNA damage.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 281363270   27 RQFHDLITCRLCRGYMIDPTTVDYCYHTYCRSCILKHLLRAvyCPECKA 75
Cdd:cd16496    10 DELENLLRCSRCASILKEPVTLGGCEHVFCRSCVGDRLGNG--CPVCDT 56

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 281363270   30 HDLiTCRLCRGYMIDPTTVDyCYHTYCRSCILK----HLLRAVYCPECKAS 76
Cdd:cd16597     4 EEL-TCSICLELFKDPVTLP-CGHNFCGVCIEKtwdsQHGSEYSCPQCRAT 52

RING finger, HC subclass, found in RING finger protein 8 (RNF8) and similar proteins; RNF8 is a telomere-associated E3 ubiquitin-protein ligase that plays an important role in DNA double-strand break (DSB) repair via histone ubiquitination. It is localized in the nucleus and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3), but not with other E2s (UbcH5, UbcH7, UbcH10, hCdc34, and hBendless). It recruits UBC13 for lysine 63-based self polyubiquitylation. Its deficiency causes neuronal pathology and cognitive decline, and its loss results in neuron degeneration. RNF8, together with RNF168, catalyzes a series of ubiquitylation events on substrates such as H2A and H2AX, with the H2AK13/15 ubiquitylation being particularly important for recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of DSBs. RNF8 mediates the ubiquitination of gammaH2AX, and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DNA damage response (DDR) and inhibits chromosomal instability. Moreover, RNF8 interacts with retinoid X receptor alpha (RXR alpha) and enhances its transcription-stimulating activity. It also regulates the rate of exit from mitosis and cytokinesis. RNF8 contains an N-terminal forkhead-associated (FHA) domain and a C-terminal C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 281363270   35 CRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAVYCPECKAS 76
Cdd:cd16535     4 CSICSELFIEAVTLN-CSHSFCSYCITEWMKRKKECPICRKP 44

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM13, TRIM59 and similar proteins; TRIM13 and TRIM59, two closely related tripartite motif-containing proteins, belong to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by an N-terminal RBCC (RING, Bbox, and coiled coil) domain, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, followed by a C-terminal transmembrane domain. TRIM13, also known as B-cell chronic lymphocytic leukemia tumor suppressor Leu5, leukemia-associated protein 5, putative tumor suppressor RFP2, RING finger protein 77 (RNF77), or Ret finger protein 2, is an endoplasmic reticulum (ER) membrane anchored E3 ubiquitin-protein ligase that interacts with proteins localized to the ER, including valosin-containing protein (VCP), a protein indispensable for ER-associated degradation (ERAD). TRIM59, also known as RING finger protein 104 (RNF104) or tumor suppressor TSBF-1, is a putative E3 ubiquitin-protein ligase that functions as a novel multiple cancer biomarker for immunohistochemical detection of early tumorigenesis.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 281363270   31 DLITCRLCrGYMIDPTTVDYCYHTYCRSCILK-------HLLRAVYCPECK 74
Cdd:cd16581     1 EELTCSIC-YNIFDDPKILPCSHTFCKNCLEKllaasgyYLLASLKCPTCR 50

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
                  ....*....|....*....|....*....|....*....|....
gi 281363270   34 TCRLCRGYMIDPTT-VDYCYHTYCRSCILKHLLRAVYCPECKAS 76
Cdd:cd16574     3 SCPICLDRFENEKAfLDGCFHAFCFTCILEWSKVKNECPLCKQP 46

Modified RING finger, HC subclass (C3HC3D-type), found in tumor necrosis factor (TNF) receptor-associated factor 7 (TRAF7) and similar proteins; TRAF7, also known as RING finger and WD repeat-containing protein 1 or RING finger protein 119 (RNF119), is an E3 ubiquitin-protein ligase involved in signal transduction pathways that lead either to activation or repression of NF-kappaB transcription factor by promoting K29-linked ubiquitination of several cellular targets, including the NF-kappaB essential modulator (NEMO) and the p65 subunit of NF-kappaB transcription factor. It is also involved in K29-linked polyubiquitination that has been implicated in lysosomal degradation of proteins. Moreover, TRAF7 is required for K48-linked ubiquitination of p53, a key tumor suppressor and a master regulator of various signaling pathways, such as those related to apoptosis, cell cycle and DNA repair. It is also required for tumor necrosis factor alpha (TNFalpha)-induced Jun N-terminal kinase activation and promotes cell death by regulating polyubiquitination and lysosomal degradation of c-FLIP protein. Furthermore, TRAF7 functions as small ubiquitin-like modifier (SUMO) E3 ligase involved in other post-translational modification, such as sumoylation. It binds to and stimulates sumoylation of the proto-oncogene product c-Myb, a transcription factor regulating proliferation and differentiation of hematopoietic cells. It potentiates MEKK3-induced AP1 and CHOP activation and induces apoptosis. Meanwhile, TRAF7 mediates MyoD1 regulation of the pathway and cell-cycle progression in myoblasts. It also plays a role in Toll-like receptors (TLR) signaling. TRAF7 contains an N-terminal domain with a modified C3HC3D-type RING-HC finger and an adjacent zinc finger, and a unique C-terminal domain that comprises a coiled coil domain and seven WD40 repeats.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 281363270   35 CRLCRGYMIDPTTVDyCYHTYCRSCILKHLLRAvyCP 71
Cdd:cd16644     8 CPLCQRVFKDPVITS-CGHTFCRRCALTAPGEK--CP 41

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 281363270   34 TCRLCRGYMIDPTTVDYCYHTYCRSCiLKHLLRAVYCPECK 74
Cdd:cd16507    11 TCGICQNLFKDPNTLIPCGHAFCLDC-LTTNASIKNCIQCK 50

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
                  ....*....|....*....|....*....|....*....|..
gi 281363270   35 CRLCRGYMID--PTTVDYCYHTYCRSCILKHLLRAV-YCPEC 73
Cdd:cd00162     1 CPICREEMNDrrPVVLLSCGHTFSRSAIARWLEGSKqKCPFC 42

Modified RING finger, HC subclass (C3HC3D-type), found in ligand of Numb protein LNX1, LNX2, and similar proteins; The ligand of Numb protein X (LNX) family, also known as PDZ and RING (PDZRN) family, includes LNX1-5, which can interact with Numb, a key regulator of neurogenesis and neuronal differentiation. LNX5 (also known as PDZK4 or PDZRN4L) shows high sequence homology to LNX3 and LNX4, but it lacks the RING domain. LNX1-4 proteins function as E3 ubiquitin ligases and have a unique domain architecture consisting of an N-terminal RING-HC finger for E3 ubiquitin ligase activity and either two or four PDZ domains necessary for substrate-binding. LNX1/LNX2-like proteins contain a modified C3HC3D-type RING-HC finger and four PDZ domains. This model corresponds to the RING finger.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 281363270   34 TCRLCRGYMIDPttVDY-CYHTYCRSCILKHLLRAVYCP 71
Cdd:cd16637     3 TCHICLQPLVEP--LDTpCGHTFCYKCLTNYLKIQQCCP 39