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        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADIE------SIEVDENLQKMV 159
Cdd:cd16734  17 CALCGGYFIDAATIVECLHSFCKTCIVRYletnKYCPMCDVQVHktrpllSIRSDKTLQDIV 78

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 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADIE------SIEVDENLQKMV 159
Cdd:cd16734  17 CALCGGYFIDAATIVECLHSFCKTCIVRYletnKYCPMCDVQVHktrpllSIRSDKTLQDIV 78

Zinc finger, C3HC4 type (RING finger);

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 15232495   108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLC 142
Cdd:pfam13923   2 CPICMDMLKDPSTTTPCGHVFCQDCILRAleasNECPLC 40

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 15232495    108 CMLCQALLYESSRCVPCTHVFCKVCLTRFKD-----CPLC 142
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLEsgnntCPIC 40

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 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADIE------SIEVDENLQKMV 159
Cdd:cd16734  17 CALCGGYFIDAATIVECLHSFCKTCIVRYletnKYCPMCDVQVHktrpllSIRSDKTLQDIV 78

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 15232495 106 FSCMLCQALLYESSRcVPCTHVFCKVCLTRFKD----CPLCGADI 146
Cdd:cd16514   2 LECSLCLRLLYEPVT-TPCGHTFCRACLERCLDhspkCPLCRTSL 45

RING finger, HC subclass, found in checkpoint with forkhead and RING finger domains protein (CHFR); CHFR, also known as RING finger protein 196 (RNF196), is a checkpoint protein that delays entry into mitosis in response to stress. It functions as an E3 ubiquitin ligase that ubiquitinates and degrades its target proteins, such as Aurora-A, Plk1, Kif22, and PARP-1, which are critical for proper mitotic transitions. It also plays an important role in cell cycle progression and tumor suppression, and is negatively regulated by SUMOylation-mediated proteasomal ubiquitylation. Moreover, CHFR is involved in the early stage of the DNA damage response, which mediates the crosstalk between ubiquitination and poly-ADP-ribosylation. CHFR contains a fork head associated (FHA) domain and a C3HC4-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLT-----RFKDCPLCGADIESI 149
Cdd:cd16503   5 CSICQDLLHDCVSLQPCMHNFCAACYSdwmerSNTECPTCRATVQRV 51

RING finger found in polycomb group RING finger protein 4 (PCGF4) and similar proteins; PCGF4, also known as 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). 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), and plays important roles in chromatin compaction and H2AK119 monoubiquitination. PCGF4 associates with the Runx1/CBFbeta transcription factor complex to silence target genes 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.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADIE------SIEVDENLQKMVDQFIEG 165
Cdd:cd16736  14 CVLCGGYFIDATTIIECLHSFCKTCIVRYletsKYCPICDVQVHktrpllNIRSDKTLQDIVYKLVPG 81

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        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 15232495 108 CMLCQALLYESSrCVPCTHVFCKVCLT----RFKDCPLCGADI----ESIEVDENLQKMVDQ 161
Cdd:cd16535   4 CSICSELFIEAV-TLNCSHSFCSYCITewmkRKKECPICRKPItsktRSLVLDNCIDKMVEN 64

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 15232495 107 SCMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADI------ESIEVDENLQKMVDQFIEG 165
Cdd:cd16737  12 TCRICKGYLIKPTTVTECLHTFCKSCIVQHfedsNDCPECGIQVhetnplEMLRLDNTLEEIIFKLVPG 80

RING finger, HC subclass, found in RING finger protein 138 (RNF138) and similar proteins; RNF138, also known as Nemo-like kinase-associated RING finger protein (NARF) or NLK-associated RING finger protein, is an E3 ubiquitin-protein ligase that plays an important role in glioma cell proliferation, apoptosis, and cell cycle. It specifically cooperates with the E2 conjugating enzyme E2-25K (Hip-2/UbcH1), regulates the ubiquitylation and degradation of T cell factor/lymphoid enhancer factor (TCF/LEF), and further suppresses Wnt-beta-catenin signaling. RNF138, together with three closely related proteins: RNF114, RNF125 and RNF166, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM).

                        10        20        30        40
                ....*....|....*....|....*....|....*....|..
gi 15232495 106 FSCMLCQALLYESSRCVPCTHVFCKVCLTRFKD-----CPLC 142
Cdd:cd16544   3 LTCPVCQEVLKDPVELPPCRHIFCKACILLALRssgarCPLC 44

Uncharacterized conserved protein, contains RING and CCCH-type Zn-fingers [General function prediction only];

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 15232495 105 PFSCMLCQALlYESSRCVPCTHVFCKVC-LTRFKD---CPLCGADIE-SIEVDENLQKMVDQ 161
Cdd:COG5152 196 PFLCGICKKD-YESPVVTECGHSFCSLCaIRKYQKgdeCGVCGKATYgRFWVVSDLQKMLNK 256

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 15232495   106 FSCMLCQALLYESSRCV--PCTHVFCKVCLTRF----KDCPLC 142
Cdd:pfam13639   1 DECPICLEEFEEGDKVVvlPCGHHFHRECLDKWlrssNTCPLC 43

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 15232495    108 CMLCQALLYESSRCVPCTHVFCKVCLTRFKD-----CPLC 142
Cdd:smart00184   1 CPICLEEYLKDPVILPCGHTFCRSCIRKWLEsgnntCPIC 40

RING finger, HC subclass, found in polycomb group RING finger protein 1 (PCGF1) and similar proteins; PCGF1, also known as nervous system Polycomb-1 (NSPc1) or RING finger protein 68 (RNF68), 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 noncanonical Polycomb repressive complex 1 (PRC1)-like BCOR complex that also contains RING1, RNF2, RYBP, SKP1, as well as the BCL6 co-repressor BCOR and the histone demethylase KDM2B, and is required to maintain the transcriptionally repressive state of some genes, such as Hox genes, BCL6 and the cyclin-dependent kinase inhibitor, CDKN1A. PCGF1 promotes cell cycle progression and enhances cell proliferation as well. It is a cell growth regulator that acts as a transcriptional repressor of p21Waf1/Cip1 via the retinoid acid response element (RARE element). Moreover, PCGF1 functions as an epigenetic regulator involved in hematopoietic cell differentiation. It cooperates with the transcription factor runt-related transcription factor 1 (Runx1) in regulating differentiation and self-renewal of hematopoietic cells. Furthermore, PCGF1 represents a physical and functional link between Polycomb function and pluripotency. PCGF1 contains a C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRF----KDCPLCGADIESIEVDENLQ 156
Cdd:cd16733  12 CYLCAGYFIDATTITECLHTFCKSCIVKYlqtsKYCPMCNIKIHETQPLLNLK 64

H2 subclass of RING (RING-H2) fingers 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 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). This family corresponds to the H2 subclass of RING (RING-H2) finger proteins that are characterized by containing C3H2C3-type canonical RING-H2 fingers or noncanonical RING-H2 finger variants, including C4HC3- (RING-CH alias RINGv), C3H3C2-, C3H2C2D-, C3DHC3-, and C4HC2H-type modified RING-H2 fingers. The canonical RING-H2 finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-H-X2-C-X(4-48)-C-X2-C, X is any amino acid and the number of X residues varies in different fingers. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-H2 finger 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 serves as a scaffold 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 15232495 108 CMLCQALLYESSRCV--PCTHVFCKVCL-----TRFKDCPLC 142
Cdd:cd16448   1 CVICLEEFEEGDVVRllPCGHVFHLACIlrwleSGNNTCPLC 42

RING finger, HC subclass, found in ligand of numb protein X 4 (LNX4); LNX4, also known as PDZ domain-containing RING finger protein 4 (PDZRN4), or SEMACAP3-like protein (SEMCAP3L), is an E3 ubiquitin-protein ligase responsible for the ubiquitination and degradation of Numb, a component of the Notch signaling pathway that functions in the specification of cell fates during development and is known to control cell numbers during neurogenesis in vertebrates. LNX4 contains an N-terminal C3HC4-type RING-HC finger, two PDZ domains, and a C-terminal LNX3 homology (LNX3H) domain.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|
gi 15232495 106 FSCMLCQALLyESSRCVPCTHVFCKVCL----TRFKDCPL 141
Cdd:cd16719   5 LKCKLCGKVL-EEPLSTPCGHVFCAGCLlpwaVQRRLCPL 43

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15232495 108 CMLCQALLyeSSRCV-PCTHVFCKVCLTRF----KDCPLCGADIEsiEVDENLQKMVDQFIEGHARIKRS------VVNG 176
Cdd:COG5432  28 CRICDCRI--SIPCEtTCGHTFCSLCIRRHlgtqPFCPVCREDPC--ESRLRGSSGSREINESHARNRDLlrkvleSLCR 103

                ....*..
gi 15232495 177 TEKEEVE 183
Cdd:COG5432 104 LPRPIKE 110

RING finger, HC subclass, found in tripartite motif-containing protein 47 (TRIM47) and similar proteins; TRIM47, also known as gene overexpressed in astrocytoma protein (GOA) or RING finger protein 100 (RNF100), 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, 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. It plays an important role in the process of dedifferentiation that is associated with astrocytoma tumorigenesis. This subfamily also includes RING finger protein 135 (RNF135). RNF135, also known as RIG-I E3 ubiquitin ligase (REUL) or Riplet, is a widely expressed E3 ubiquitin-protein ligase that consists of an N-terminal C3HC4-type RING-HC finger and C-terminal B30.2/SPRY and PRY motifs, but lacks the B-box and coiled-coil domains that are also typically present in TRIM proteins. RNF135 serves as a specific retinoic acid-inducible gene-I (RIG-I)-interacting protein that ubiquitinates RIG-I and specifically stimulates RIG-I-mediated innate antiviral activity to produce antiviral type-I interferon (IFN) during the early phase of viral infection. It also has been identified as a bio-marker and therapy target of glioblastoma. It associates with the ERK signal transduction pathway and plays a role in glioblastoma cell proliferation, migration and cell cycle.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 15232495 106 FSCMLCQALLYESSrCVPCTHVFCKVCLTRFKD--------CPLC 142
Cdd:cd16604   1 LSCPICLDLLKDPV-TLPCGHSFCMGCLGALWGagrggrasCPLC 44

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 15232495 106 FSCMLCQALLYESSRcVPCTHVFCKVC----LTRFKDCPLCGADIE 147
Cdd:cd16547   4 LICSICHGVLRCPVR-LSCSHIFCKKCilqwLKRQETCPCCRKEVK 48

RING finger, HC subclass, found in peroxin-10 (PEX10) and similar proteins; PEX10, also known as peroxisome biogenesis factor 10, peroxisomal biogenesis factor 10, peroxisome assembly protein 10, or RING finger protein 69 (RNF69), is an integral peroxisomal membrane protein with two transmembrane regions and a C3HC4-type RING-HC finger within its cytoplasmically exposed C-terminus. It plays an essential role in peroxisome assembly, import of target substrates, and recycling or degradation of protein complexes and amino acids. It is an essential component of the spinal locomotor circuit, and thus its mutations may be involved in peroxisomal biogenesis disorders (PBD). Mutations in human PEX10 also result in autosomal recessive ataxia. Moreover, PEX10 functions as an E3-ubiquitin ligase with an E2, UBCH5C. It mono- or poly-ubiquitinates PEX5, a key player in peroxisomal matrix protein import, in a UBC4-dependent manner, to control PEX5 receptor recycling or degradation. It also links the E2 ubiquitin conjugating enzyme PEX4 to the protein import machinery of the peroxisome.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 15232495 106 FSCMLCqalLYE--SSRCVPCTHVFCKVCLT---RFKD-CPLCGADIE 147
Cdd:cd16527   1 RKCSLC---LEErrHPTATPCGHLFCWSCITewcNEKPeCPLCREPFQ 45

RING finger, H2 subclass, found in RING finger protein 165 (RNF165) and similar proteins; RNF165, also known as Arkadia-like 2, Arkadia2, or Ark2C, is an E3 ubiquitin ligase with homology to the C-terminal half of RNF111. It is expressed specifically in the nervous system, and can serve to amplify neuronal responses to specific signals. It acts as a positive regulator of bone morphogenetic protein (BMP)-Smad signaling that is involved in motor neuron (MN) axon elongation. RNF165 contains two serine rich domains, a nuclear localization signal, an NRG-TIER domain, and a C-terminal C3H2C3-type RING-H2 finger that is responsible for the enhancement of BMP-Smad1/5/8 signaling in the spinal cord.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*..
gi 15232495 108 CMLCQALLY--ESSRCVPCTHVFCKVCLTRF----KDCPLCGADIES 148
Cdd:cd16682  10 CTICLSMLEdgEDVRRLPCMHLFHQLCVDQWlamsKKCPICRVDIET 56

second RING finger, HC subclass, found in Arabidopsis thaliana ORTHRUS and similar proteins; This subfamily includes Arabidopsis thaliana ORTHRUS 1-5. They are E3 ubiquitin-protein ligases that may participate in CpG methylation-dependent transcriptional regulation and/or epigenetic transcriptional silencing. ORTHRUS 1 mediates ubiquitination with the E2 ubiquitin-conjugating enzymes UBC11, UBC8 and UBC8 homologs (e.g. UBC10, UBC11, UBC28 and UBC29) but not with UBC27, UBC30, UBC32, UBC34 and UBC36. ORTHRUS 2 and 5 mediate ubiquitination with the E2 ubiquitin-conjugating enzyme UBC11. ORTHRUS 1 and 2 promote methylation-mediated gene silencing leading, for example, to early flowering. They can bind to CpG, CpNpG, and CpNpN DNA motifs, with a strong preference for methylated forms, and with highest affinity for CpG substrates. Members of this subfamily contain two typical C3HC4-type RING-HC fingers. This model corresponds to the second one.

                        10        20
                ....*....|....*....|....*...
gi 15232495 106 FSCMLCQALLYESSrCVPCTHVFCKVCL 133
Cdd:cd23139   6 FGCQICKKVLSLPV-STPCGHNFCKACL 32

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.

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gi 15232495 108 CMLCQALLYESSRCVPCTHVFCKVCLTRFKD------CPLC 142
Cdd:cd16749   3 CPVCFEKLDVTAKVLPCQHTFCKPCLQRIFKarkelrCPEC 43