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 4566495     103 CPICLDRFDNVSYLDRCLHKFCFRCVQEW-SKNKAECPLC 141
Cdd:pfam00097    1 CPICLEEPKDPVTLLPCGHLFCSKCIRSWlESGNVTCPLC 40

N1R/p28-like protein; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 4566495     96 DASPDSKCPICLDRFDNVSY-------LDRCLHKFCFRCVQEWSKNKAECPLCKQPFDSIFHS 151
Cdd:PHA02929  170 NRSKDKECAICMEKVYDKEIknmyfgiLSNCNHVFCIECIDIWKKEKNTCPVCRTPFISVIKS 232

RING finger, HC subclass, found in Equid alphaherpesvirus 1 (Equine herpesvirus 1/EHV-1) regulatory protein and similar proteins; EHV-1 regulatory protein belongs to the Vmw110 (IPC0) protein family. It contains a typical C3HC4-type RING-HC finger and binds zinc stably.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 4566495   103 CPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAECPLCKQPFDSIFHS 151
Cdd:cd23130    3 CPICLDDPEDEAITLPCLHQFCYTCILRWLQTSPTCPLCKTPVTSIIHS 51

Modified RING finger, HC subclass (C3HC3D-type), found in PHD and RING finger domain-containing protein 1 (PHRF1) and similar proteins; PHRF1, also known as KIAA1542, or CTD-binding SR-like protein rA9, is a ubiquitin ligase which induces the ubiquitination of TGIF (TG-interacting factor) at lysine 130. It acts as a tumor suppressor that promotes the transforming growth factor (TGF)-beta cytostatic program through selective release of TGIF-driven promyelocytic leukemia protein (PML) inactivation. PHRF1 contains a plant homeodomain (PHD) finger and a modified C3HC3D-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 4566495   100 DSKCPICLDRFDN--VSYLDRCLHKFCFRCVQEWSKNKAECPLCKQPF 145
Cdd:cd16635    4 SESCPICLNTFRDqaVGTPESCDHIFCLDCILEWSKNANTCPVDRIVF 51

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 4566495   102 KCPICLDRFDNVSYLDrCLHKFCFRCVQEW-SKNKAECPLC 141
Cdd:cd16449    2 ECPICLERLKDPVLLP-CGHVFCRECIRRLlESGSIKCPIC 41

RING finger, H2 subclass, found in the PA-TM-RING ubiquitin ligase family; The PA-TM-RING family represents a group of transmembrane-type E3 ubiquitin ligases, which has been characterized by an N-terminal transient signal peptide, a PA (protease-associated) domain, a TM (transmembrane) domain, as well as a C-terminal C3H2C3-type RING-H2 finger domain. It includes RNF13, RNF167, ZNRF4 (zinc and RING finger 4), GRAIL (gene related to anergy in lymphocytes)/RNF128, RNF130, RNF133, RNF148, RNF149 and RNF150 (which are more closely related), as well as RNF43 and ZNRF3, which have substantially longer C-terminal tail extensions compared with the others. PA-TM-RING proteins are expressed at low levels in all mammalian tissues and species, but they are not present in yeast. They play a common regulatory role in intracellular trafficking/sorting, suggesting that abrogation of their function may result in dysregulation of cellular signaling events in cancer.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 4566495   103 CPICLDRF---DNVSYLdRCLHKFCFRCVQEWSKNKAECPLCK 142
Cdd:cd16454    2 CAICLEEFkegEKVRVL-PCNHLFHKDCIDPWLEQHNTCPLCR 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 4566495      103 CPICLDRFDNVSYLDRCLHKFCFRCVQEW-SKNKAECPLC 141
Cdd:smart00184    1 CPICLEEYLKDPVILPCGHTFCRSCIRKWlESGNNTCPIC 40

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Deltex3 (DTX3) and similar proteins; DTX3, also known as RING finger protein 154 (RNF154), is an E3 ubiquitin-protein ligase that belongs to the Deltex (DTX) family. In contrast to other DTXs, DTX3 does not contain two N-terminal Notch-binding WWE domains, but a short unique N-terminal domain, suggesting it does not interact with the intracellular domain of Notch. Its C-terminal region includes a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 4566495   100 DSKCPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAECPLCK 142
Cdd:cd16711    1 EETCPICLGEIQNKKTLDKCKHSFCEDCITRALQVKKACPMCG 43

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 4566495   101 SKCPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAECPLCK 142
Cdd:cd16506    1 DTCPICLDEIQNKKTLEKCKHSFCEDCIDRALQVKPVCPVCG 42

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 4566495   103 CPICLDRFDN-VSylDRCLHKFCFRCVQEW---SKNKAECPLCKQPFDSifHSVRAEDDFKEYV 162
Cdd:cd16498   19 CPICLELLKEpVS--TKCDHQFCRFCILKLlqkKKKPAPCPLCKKSVTK--RSLQESTRFKQLV 78

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 4566495   100 DSKCPICLDRFDNVSYLDRCLHKFCFRCVQEWSKN-KAECPLCKQPFDSiFHSVRAEDDF 158
Cdd:cd16531    1 ELMCPICLGIIKNTMTVKECLHRFCAECIEKALRLgNKECPTCRKHLPS-RRSLRPDPNF 59

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 4566495   103 CPICLDRFDNVSYLDrCLHKFCFRCVQEW-SKN---KAECPLCKQ 143
Cdd:cd16623   11 CPICLDFFSHPISLS-CAHIFCFDCIQKWmTKRedsILTCPLCRK 54

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        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 4566495   100 DSKCPICLDRFDNVSYLdRCLHKFCFRCV---QEWSKNKAECPLCKQPFD 146
Cdd:cd23133    3 TLTCSICQGIFMNPVYL-RCGHKFCEACLllfQEDIKFPAYCPMCRQPFN 51

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.

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                 ....*....|....*....|....*....|....*....|....*....|.
gi 4566495    99 PDSKCPICLDRFDNVSYLDRCLHKFCFRCVQEW-SKNKAECPLCKQPFDSI 148
Cdd:cd16503    1 ENLTCSICQDLLHDCVSLQPCMHNFCAACYSDWmERSNTECPTCRATVQRV 51

RING finger, HC subclass, found in tripartite motif-containing protein TRIM65 and similar proteins; TRIM65 is an E3 ubiquitin-protein ligase that interacts with the innate immune receptor MDA5, enhancing its ability to stimulate interferon-beta signaling. It functions as a potential oncogenic protein that negatively regulates p53 through ubiquitination, providing insight into the development of novel approaches targeting TRIM65 for non-small cell lung carcinoma (NSCLC) treatment, and also overcoming chemotherapy resistance. Moreover, TRIM65 negatively regulates microRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. TRIM65 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 4566495   103 CPICLDRF-DNVSYldRCLHKFCFRCVQEWSKNKA----ECPLCKQPF 145
Cdd:cd16609    6 CSICLGLYqDPVTL--PCQHSFCRACIEDHWRQKDegsfSCPECRAPF 51

RING finger, H2 subclass, found in Arabidopsis thaliana RING-H2 finger A1a (RHA1A), A1b (RHA1B) and similar proteins; This subfamily includes Arabidopsis thaliana RHA1A, RHA1B and XERICO. RHA1A is a probable E3 ubiquitin-protein ligase that may possess E3 ubiquitin ligase activity in vitro. RHA1B possesses E3 ubiquitin-protein ligase activity when associated with the E2 enzyme UBC8 in vitro. XERICO functions on abscisic acid homeostasis at post-translational level, probably through ubiquitin/proteasome-dependent substrate-specific degradation. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

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                 ....*....|....*....|....*....|....*....|....*....|
gi 4566495   100 DSKCPICLDRFDN---VSYLDRCLHKFCFRCVQEW-SKNKAECPLCKQPF 145
Cdd:cd23121    1 DDCCAICLSDFNSdekLRQLPKCGHIFHHHCLDRWiRYNKITCPLCRADL 50

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 4566495   103 CPICLDRFDNVSYLDRCLHKFCFRCVQE-WSKNKAECPLCKQP 144
Cdd:cd16544    5 CPVCQEVLKDPVELPPCRHIFCKACILLaLRSSGARCPLCRGP 47

RING finger, H2 subclass, found in RING finger proteins RNF24, RNF122, and similar proteins; This subfamily includes RNF24, RNF122, and similar proteins. RNF24 is an intrinsic membrane protein localized in the Golgi apparatus. It specifically interacts with the ankyrin-repeats domains (ARDs) of TRPC1, -3, -4, -5, -6, and -7, and affects TRPC intracellular trafficking without affecting their activity. RNF122 is a RING finger protein associated with HEK 293T cell viability. It is localized to the endoplasmic reticulum (ER) and the Golgi apparatus, and overexpressed in anaplastic thyroid cancer cells. RNF122 functions as an E3 ubiquitin ligase that can ubiquitinate itself and undergo degradation through its RING finger in a proteasome-dependent manner. Both RNF24 and RNF122 contain an N-terminal transmembrane domain and a C-terminal C3H2C3-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 4566495   102 KCPICLDRFDNVSYLDRCL--HKFCFRCVQEWSKNKAECPLCKQP 144
Cdd:cd16469    2 TCAVCLEEFKLKEELGVCPcgHAFHTKCLKKWLEVRNSCPICKSP 46

RING finger, HC subclass, found in helicase-like transcription factor (HLTF) and similar proteins; HLTF, also known as DNA-binding protein/plasminogen activator inhibitor 1 regulator, HIP116, RING finger protein 80, SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 3, or sucrose nonfermenting protein 2-like 3, is a yeast RAD5 homolog found in mammals. It has both E3 ubiquitin ligase and DNA helicase activities, and plays a pivotal role in the template-switching pathway of DNA damage tolerance. It is involved in Lys-63-linked poly-ubiquitination of proliferating cell nuclear antigen (PCNA) at Lys-164 and in the regulation of DNA damage tolerance. It shows double-stranded DNA translocase activity with 3'-5' polarity, thereby facilitating regression of the replication fork. HLTF contains an N-terminal HIRAN (HIP116 and RAD5 N-terminal) domain, a SWI/SNF helicase domain that is divided into N- and C-terminal parts by an insertion of a C3HC4-type RING-HC finger involved in the poly-ubiquitination of PCNA.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 4566495   100 DSKCPICLDRFdNVSYLDRCLHKFCFRCVQE-WSKNKAECPLCKQP 144
Cdd:cd16509    3 DEECAICLDSL-TNPVITPCAHVFCRRCICEvIQREKAKCPMCRAP 47

RING finger, HC subclass, found in Arabidopsis thaliana BRCA1-associated RING domain protein 1 (AtBARD1) and similar proteins; AtBARD1, also called protein REPRESSOR OF WUSCHEL 1, binds specifically to H3K4me3 regions of target gene (e.g. WUS and WOX5) promoters to repress their transcription via chromatin remodeling. It is required for the shoot apical meristem (SAM) organization and maintenance, by confining WUS expression to the organizing center, and for the quiescent center (QC) development in the root apical meristem (RAM), by repressing WOX5 expression in the root proximal meristem. AtBARD1 plays a role in DNA repair and in cell-cycle control. It is required for the repair of DNA double-strand breaks (DSBs), both natural and induced by genotoxic stress, by homologous recombination (HR). AtBARD1 contains a typical C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 4566495   102 KCPICLDRFdNVSYLDRCLHKFCFRCVQEWSKNKAECPLCKQPFDS 147
Cdd:cd23146    6 KCPICLKLL-NRPVLLPCDHIFCSSCITDSTKVGSDCPVCKLPYHS 50

RING finger, HC subclass, found in postreplication repair protein RAD18 and similar proteins; RAD18, also known as HR18 or RING finger protein 73 (RNF73), is an E3 ubiquitin-protein ligase involved in post replication repair of UV-damaged DNA via its recruitment to stalled replication forks. It associates to the E2 ubiquitin conjugating enzyme UBE2B to form the UBE2B-RAD18 ubiquitin ligase complex involved in mono-ubiquitination of DNA-associated PCNA on K164. It also interacts with another E2 ubiquitin conjugating enzyme RAD6 to form a complex that monoubiquitinates proliferating cell nuclear antigen at stalled replication forks in DNA translesion synthesis. Moreover, Rad18 is a key factor in double-strand break DNA damage response (DDR) pathways via its association with K63-linked polyubiquitylated chromatin proteins. It can function as a mediator for DNA damage response signals to activate the G2/M checkpoint in order to maintain genome integrity and cell survival after ionizing radiation (IR) exposure. RAD18 contains a C3HC4-type RING-HC finger, a ubiquitin-binding zinc finger domain (UBZ), a SAP (SAF-A/B, Acinus and PIAS) domain, and a RAD6-binding domain (R6BD).

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 4566495   102 KCPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAECPLCKQP 144
Cdd:cd16529    6 RCPICFEYFNTAMMITQCSHNYCSLCIRRFLSYKTQCPTCRAA 48

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

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                 ....*....|....*....|....*....|....*....|....*..
gi 4566495   103 CPICLDRF-DNVSyLDrCLHKFCFRCV-QEW--SKNKAECPLCKQPF 145
Cdd:cd16594    8 CPICLDYFtDPVT-LD-CGHSFCRACIaRCWeePETSASCPQCRETC 52

Modified RING finger, HC subclass (C2H2C4-type), found in E3 ubiquitin-protein ligase MDM2, protein MDM4 and similar proteins; MDM2 (also known as HDM2) and MDM4 (also known as MDMX or HDMX) are the primary p53 tumor suppressor negative regulators. They have non-redundant roles in the regulation of p53. MDM2 mainly functions to control p53 stability, while MDM4 controls p53 transcriptional activity. Both MDM2 and MDM4 contain an N-terminal p53-binding domain, a RanBP2-type zinc finger (zf-RanBP2) domain near the central acidic region, and a C-terminal modified C2H2C4-type RING-HC finger. Mdm2 can form homo-oligomers through its RING domain and displays E3 ubiquitin ligase activity that catalyzes the attachment of ubiquitin to p53 as an essential step in the regulation of its levels in cells. Despite its RING domain and structural similarity with MDM2, MDM4 does not homo-oligomerize and lacks ubiquitin-ligase function, but inhibits the transcriptional activity of p53. In addition, both their RING domains are responsible for the hetero-oligomerization, which is crucial for the suppression of P53 activity during embryonic development and the recruitment of E2 ubiquitin-conjugating enzymes. Moreover, MDM2 and MDM4 can be phosphorylated and destabilized in response to DNA damage stress. In response to ribosomal stress, MDM2-mediated p53 ubiquitination and degradation can be inhibited through the interaction with ribosomal proteins L5, L11, and L23. However, MDM4 is not bound to ribosomal proteins, suggesting its different response to regulation by small basic proteins such as ribosomal proteins and ARF.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 4566495   103 CPICLDRFDNVSYLDRCL-HKF-CFRCVQEWSKNKAECPLCKQPFDSIFH 150
Cdd:cd16646    3 CVICLSRPRTAAIVHGKTgHQVaCYTCAKKLKRRGKPCPVCRRPIQNVIK 52

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
                 ....*....|....*....|....*....|....*....|....*....
gi 4566495   102 KCPICLDRFDNVSYLDrCLHKFCFRCVQEWSKNKAE-----CPLCKQPF 145
Cdd:cd16598    6 TCSICLDYLRDPVTID-CGHNFCRSCITDYCPISGGherpvCPLCRKPF 53

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 4566495   103 CPICLDRFD--NVSYLDRCLHKFCFRCVQEWSKNK-AECPLCK 142
Cdd:cd16448    1 CVICLEEFEegDVVRLLPCGHVFHLACILRWLESGnNTCPLCR 43

RING finger, HC subclass, found in tripartite motif-containing protein TRIM58 and similar proteins; TRIM58, also known as protein BIA2, is an erythroid E3 ubiquitin-protein ligase induced during late erythropoiesis. It binds and ubiquitinates the intermediate chain of the microtubule motor dynein (DYNC1LI1/DYNC1LI2), stimulating the degradation of the dynein holoprotein complex. It may participate in the erythroblast enucleation process through regulation of nuclear polarization. TRIM58 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 4566495   100 DSKCPICLDRFDNVSYLDrCLHKFCFRCVQEWSKNKA-------ECPLCKQPF 145
Cdd:cd16606    2 EARCPVCLDFLQEPVSVD-CGHSFCLRCISEFCEKSDsaqggvyACPQCRGPF 53

Modified RING finger, HC subclass (C3HC3D-type), found in neuregulin receptor degradation protein-1 (Nrdp1) and similar proteins; Nrdp1 (referred to as FLRF in mice), also known as RING finger protein 41 (RNF41), is an E3 ubiquitin-protein ligase that plays a critical role in the regulation of cell growth and apoptosis, inflammation and production of reactive oxygen species (ROS), as well as in doxorubicin (DOX)-induced cardiac injury. It promotes the degradation of the epidermal growth factor receptor (EGFR/ErbB) family member, ErbB3, which is independent of growth factor stimulation. It also promotes M2 macrophage polarization by ubiquitinating and activating transcription factor CCAAT/enhancer-binding protein beta (C/EBPbeta) via Lys-63-linked ubiquitination. Moreover, Nrdp1 interacts with and modulates the activity of Parkin, a causative protein for early onset recessive juvenile parkinsonism (AR-JP). It also interacts with ubiquitin-specific protease 8 (USP8), which is involved in trafficking of various transmembrane proteins. Furthermore, Nrdp1 inhibits basal lysosomal degradation and enhances ectodomain shedding of JAK2-associated cytokine receptors. Its phosphorylation by the kinase Par-1b (also known as MARK2) is required for epithelial cell polarity. Nrdp1 contains an N-terminal modified C3HC3D-type RING-HC finger required for enhancing ErbB3 degradation, a B-box, a coiled-coil domain responsible for Nrdp1 oligomerization, and a C-terminal ErbB3-binding domain.

                         10        20        30
                 ....*....|....*....|....*....|....*...
gi 4566495   103 CPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAECPL 140
Cdd:cd16634    4 CPICSGVLEEPLQAPHCEHAFCNACITEWLSRQQTCPV 41

Modified RING finger, C3HGC3-type, found in RING finger and WD repeat domain-containing protein 3 (RFWD3) and similar proteins; RFWD3, also known as RING finger protein 201 (RNF201) or FLJ10520, is an E3 ubiquitin-protein ligase that forms a complex with Mdm2 and p53 to synergistically ubiquitinate p53 and acts as a positive regulator of p53 stability in response to DNA damage. It is phosphorylated by checkpoint kinase ATM/ATR and the phosphorylation mutant fails to stimulate p53 ubiquitination. RFWD3 also functions as a novel replication protein A (RPA)-associated protein involved in DNA replication checkpoint control. RFWD3 contains an N-terminal SQ-rich region followed by a RING finger domain that exhibits robust E3 ubiquitin ligase activity toward p53, a coiled-coil domain and three WD40 repeats in the C-terminus, the latter two of which may be responsible for protein-protein interaction. The RING finger in this family is a modified C3HGC3-type RING finger, but not a canonical C3H2C3-type RING-H2 finger or C3HC4-type RING-HC finger.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 4566495   100 DSKCPICLDRFDN-----VSYLdRCLHKFCFRCVQEW-SKNKAECPLCKQPF 145
Cdd:cd16450    2 GNTCPICFEPWTSsgehrLVSL-KCGHLFGYSCIEKWlKGKGKKCPQCNKKA 52

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
                 ....*....|....*....|....*....|....*....|....*....|.
gi 4566495    99 PDS-KCPICLDRFDNVSYLDRCLHKFCFRCVQEW-SKNKAECPLCKQPFDS 147
Cdd:cd16620    1 PDElKCPICKDLMKDAVLTPCCGNSFCDECIRTAlLEEDFTCPTCKEPDVS 51

RING finger, HC subclass, found in RING finger protein 219 (RNF219) and similar proteins; RNF219 may function as a modulator of late-onset Alzheimer's disease (LOAD) associated amyloid beta A4 precursor protein (APP) endocytosis and metabolism. It genetically interacts with apolipoprotein E epsilon4 allele (APOE4). Thus, a genetic variant of RNF219 was found to affect amyloid deposition in human brain and LOAD age-of-onset. Moreover, common genetic variants at the RNF219 locus had been associated with alternations in lipid metabolism, cognitive performance and central nervous system ventricle volume. RNF219 contains a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 4566495   103 CPICLDRfdnVSYLDRC--LHKFCFRCVQEWSKNKAECPLCKQP 144
Cdd:cd16562    4 CHICLGK---VRQPVICsnNHVFCSSCMDVWLKNNNQCPACRVP 44

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 4566495   102 KCPICLDRFDNVSYLDrCLHKFCFRCVQEWSKNKAECPLCKQPFDSIF 149
Cdd:cd16546    2 ECPICLQTCIHPVKLP-CGHIFCYLCVKGVAWQSKRCALCRQEIPEDF 48

RING finger, HC subclass, found in Arabidopsis thaliana proteolysis 1 protein (PRT1) and similar proteins; PRT1, also called RING-type E3 ubiquitin transferase PRT1, is an E3 ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins. It functions in the N-end rule pathway of protein degradation, where it specifically recognizes and ubiquitinates proteins with an N-terminal bulky aromatic amino acid (Phe). It does not act on aliphatic hydrophobic and basic N-terminal residues (Arg or Leu) containing proteins. PRT1 contains a typical C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 4566495   103 CPICLDR-FDNVsyLDRCLHKFCFRCVQEWSKN--KAECPLCKQPFD 146
Cdd:cd23132    5 CCICLDLlYKPV--VLECGHVFCFWCVHRCMNGydESHCPLCRRPYD 49

RING finger, HC subclass, found in SH3 domain-containing RING finger proteins SH3RF1, SH3RF2, SH3RF3, and similar proteins; SH3RF1, also known as plenty of SH3s (POSH), RING finger protein 142 (RNF142), or SH3 multiple domains protein 2 (SH3MD2), is a trans-Golgi network-associated pro-apoptotic scaffold protein with E3 ubiquitin-protein ligase activity. 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) that is required for pro-apoptotic JNK activation. SH3RF3, also known as plenty of SH3s 2 (POSH2) or SH3 multiple domains protein 4 (SH3MD4), is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in the screen for interacting partners of p21-activated kinase 2 (PAK2) and may play a role in regulating c-Jun N-terminal kinase (JNK) mediated apoptosis in certain conditions. Members of this subfamily contain an N-terminal C3HC4-type RING-HC finger responsible for the E3 ligase activity and four Src Homology 3 (SH3) domains, which are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 4566495   102 KCPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKAE--CPLCK 142
Cdd:cd16570    2 ECPVCLERLDVSAKVLPCQHTFCKRCLQIIVASRGElrCPECR 44

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 4566495   103 CPICLDRFDNVSYLDrCLHKFCFRCVQEWSKNKA---ECPLCKQ 143
Cdd:cd16767    9 CSICLDRYKNPKVLP-CLHTFCERCLQNYIPAHSltlSCPVCRQ 51

RING finger, H2 subclass, found in RING finger proteins RNF111, RNF165, and similar proteins; The family includes RING finger proteins RNF111, RNF165, and similar proteins. RNF111, also known as Arkadia, is a nuclear E3 ubiquitin-protein ligase that targets intracellular effectors and modulators of transforming growth factor beta (TGF-beta)/Nodal-related signaling for polyubiquitination and proteasome-dependent degradation. It also interacts with the clathrin-adaptor 2 (AP2) complex and regulates endocytosis of certain cell surface receptors, leading to modulation of epidermal growth factor (EGF) and possibly other signaling pathways. The N-terminal half of RNF111 harbors three SUMO-interacting motifs (SIMs). It thus functions as a SUMO-targeted ubiquitin ligase (STUbL) that directly links nonproteolytic ubiquitylation and SUMOylation in the DNA damage response, as well as triggers degradation of signal-induced polysumoylated proteins, such as the promyelocytic leukemia protein (PML). 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. Both RNF165 and RNF111 contain a C-terminal C3H2C3-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 4566495   102 KCPICLDRF---DNVSYLDrCLHKFCFRCVQEWSKNKAECPLCK 142
Cdd:cd16474    2 KCTICLSDFeegEDVRRLP-CMHLFHQECVDQWLSTNKRCPICR 44

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 4566495   103 CPICLDRFDNVSYLDrCLHKFCFRCV-QEWSKNKAE--------CPLCKQPF 145
Cdd:cd16592    7 CPICLGYFKDPVILD-CEHSFCRACIaRHWGQEAMEgngaegvfCPQCGEPC 57

RING finger, HC subclass, found in RING finger protein 10 (RNF10) and similar proteins; RNF10 is an E3 ubiquitin-protein ligase that interacts with mesenchyme Homeobox 2 (MEOX2) transcription factor, a regulator of the proliferation, differentiation and migration of vascular smooth muscle cells and cardiomyocytes; it enhances Meox2 activation of the p21 promoter. It also regulates the expression of myelin-associated glycoprotein (MAG) genes and is required for myelin production in Schwann cells of the peripheral nervous system. Moreover, RNF10 regulates retinoic acid-induced neuronal differentiation and the cell cycle exit of P19 embryonic carcinoma cells. RNF10 contains a C3HC4-type RING-HC finger and three putative nuclear localization signals.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 4566495   102 KCPICLD-----RfdnvsyLDRCLHKFCFRCV--------QEWSKnkaeCPLCkqpFDSI 148
Cdd:cd16536    2 QCPICLEppvapR------ITRCGHIFCWPCIlrylslseKKWRK----CPIC---FESI 48

RING finger, HC subclass, found in RING finger protein 166 (RNF166) and similar proteins; RNF166 is encoded by the gene RNF166 targeted by thyroid hormone receptor alpha1 (TRalpha1), which is important in brain development. It plays an important role in RNA virus-induced interferon-beta production by enhancing the ubiquitination of TRAF3 and TRAF6. RNF166, together with three closely related proteins: RNF114, RNF125 and RNF138, 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 4566495   103 CPICLDRFDNVSYLDRCLHKFCFRCVQEWSKNKA-ECPLCKQPF 145
Cdd:cd16549    4 CPICLEVYHKPVVITSCGHTFCGECLQPCLQVASpLCPLCRMPF 47

RING finger, HC subclass, found in Arabidopsis thaliana RING membrane-anchor proteins (AtRMAs) and similar proteins; AtRMAs, including AtRma1, AtRma2, and AtRma3, are endoplasmic reticulum (ER)-localized Arabidopsis homologs of human outer membrane of the ER-anchor E3 ubiquitin-protein ligase, RING finger protein 5 (RNF5). AtRMAs possess E3 ubiquitin ligase activity, and may play a role in the growth and development of Arabidopsis. The AtRMA1 and AtRMA3 genes are predominantly expressed in major tissues, such as cotyledons, leaves, shoot-root junction, roots, and anthers, while AtRMA2 expression is restricted to the root tips and leaf hydathodes. AtRma1 probably functions with the Ubc4/5 subfamily of E2. AtRma2 is likely involved in the cellular regulation of ABP1 expression levels through interacting with auxin binding protein 1 (ABP1). AtRMA proteins contain an N-terminal C3HC4-type RING-HC finger and a trans-membrane-anchoring domain in their extreme C-terminal region.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 4566495   103 CPICLDRF-DNVsyLDRCLHKFCFRCVQEW---SKNKAECPLCK 142
Cdd:cd16745    3 CNICLDLAqDPV--VTLCGHLFCWPCLHKWlrrQSSQPECPVCK 44

RING finger, HC subclass, found in tripartite motif-containing protein 31 (TRIM31) and similar proteins; TRIM31 is an E3 ubiquitin-protein ligase that primarily localizes to the cytoplasm, but is also associated with the mitochondria. It can negatively regulate cell proliferation and may be a potential biomarker of gastric cancer as it is overexpressed from the early stage of gastric carcinogenesis. TRIM31 is downregulated in non-small cell lung cancer and serves as a potential tumor suppressor. It interacts with p52 (Shc) and inhibits Src-induced anchorage-independent growth. TRIM31 belongs 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, as well as an uncharacterized region positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 4566495   103 CPICLDRFDNVSYLDrCLHKFCFRCVQ---EWSKNKAECPLC 141
Cdd:cd16582    4 CPICLDILQKPVTID-CGHNFCLQCITqigETSCGFFKCPLC 44

RING finger, HC subclass, found in SH3 domain-containing RING finger protein 3 (SH3RF3) and similar proteins; SH3RF3, also known as plenty of SH3s 2 (POSH2) or SH3 multiple domains protein 4 (SH3MD4), is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in a screen for interacting partners of p21-activated kinase 2 (PAK2). It may play a role in regulating c-Jun N-terminal kinase (JNK) mediated apoptosis in certain conditions. It also interacts with GTP-loaded Rac1. SH3RF3 is highly homologous to SH3RF1. Both contain an N-terminal C3HC4-type RING-HC finger responsible for the E3 ligase activity and four Src Homology 3 (SH3) domains, which are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 4566495   102 KCPICLDRFDNVSYLDRCLHKFCFRCVQEW--SKNKAECPLCK 142
Cdd:cd16750    4 ECSVCLERLDTTSKVLPCQHTFCRRCLESIvsSRKELRCPECR 46

RING finger, H2 subclass, found in RING finger protein 215 (RNF215) and similar proteins; This family includes uncharacterized protein RNF215 and similar proteins. Although its biological function remains unclear, RNF215 shares high sequence similarity with PA-TM-RING ubiquitin ligases, which have been characterized by containing an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane (TM) domain and a C-terminal C3H2C3-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 4566495   103 CPICLDRFDNVSYLD--RCLHKFCFRCVQEWSKNKAECPLCK 142
Cdd:cd16670    3 CAVCLDQFYKNQCLRvlPCLHEFHRDCVDPWLLLQQTCPLCK 44

RING finger, HC subclass, found in tripartite motif-containing protein 8 (TRIM8) and similar proteins; TRIM8, also known as glioblastoma-expressed RING finger protein (GERP) or RING finger protein 27 (RNF27), is a probable E3 ubiquitin-protein ligase that may promote proteasomal degradation of suppressor of cytokine signaling 1 (SOCS1) and further regulate interferon-gamma signaling. It functions as a new p53 modulator that stabilizes p53 impairing its association with MDM2 and inducing the reduction of cell proliferation. TRIM8 deficit dramatically impairs p53 stabilization and activation in response to chemotherapeutic drugs. TRIM8 also modulates tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta)-triggered nuclear factor-kappaB (NF- kappa B) activation by targeting transforming growth factor beta (TGFbeta) activated kinase 1 (TAK1) for K63-linked polyubiquitination. Moreover, TRIM8 modulates translocation of phosphorylated STAT3 into the nucleus through interaction with Hsp90beta and consequently regulates transcription of Nanog in embryonic stem cells. It also interacts with protein inhibitor of activated STAT3 (PIAS3), which inhibits IL-6-dependent activation of STAT3. TRIM8 belongs to the C-V 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 domain, as well as an uncharacterized region positioned C-terminal to the RBCC domain. The coiled coil domain is required for homodimerization and the region immediately C-terminal to the RING motif is sufficient to mediate the interaction with SOCS1.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 4566495   103 CPICLDRFDNVSYLDrCLHKFCFRCVQE-WSKNKA--ECPLCKQPF 145
Cdd:cd16580   14 CPICLHVFVEPVQLP-CKHNFCRGCIGEaWAKDAGlvRCPECNQAY 58

Modified RING finger, HC subclass (C3HC5-type), found in neuralized-like protein NEURL1A, NEURL1B, and similar proteins; This subfamily includes Drosophila neuralized (D-neu) protein, and its two mammalian homologs, NEURL1A and NEURL1B. D-neu is a regulator of the developmentally important Notch signaling pathway. NEURL1A, also known as NEURL1, NEU, neuralized 1, or RING finger protein 67 (RNF67), is a mammalian homolog of D-neu. It functions as an E3 ubiquitin-protein ligase that directly interacts with and monoubiquitinates cytoplasmic polyadenylation element-binding protein 3 (CPEB3), an RNA binding protein and a translational regulator of local protein synthesis, which facilitates hippocampal plasticity and hippocampal-dependent memory storage. It also acts as a potential tumor suppressor that causes apoptosis and downregulates Notch target genes in medulloblastoma. NEURL1B, also known as neuralized-2 (NEUR2) or neuralized-like protein 3, is another mammalian homolog of D-neu protein. It functions as an E3 ubiquitin-protein ligase that interacts with and ubiquitinates Delta. Thus, it plays a role in the endocytic pathways for Notch signaling by working cooperatively with another E3 ligase, Mind bomb-1 (Mib1), in Delta endocytosis to hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs)-positive vesicles. Members of this subfamily contain two neuralized homology regions (NHRs) responsible for Neural-ligand interactions and a modified C3HC5-type RING-HC finger required for ubiquitin ligase activity. The C3HC5-type RING-HC finger is distinguished from typical C3HC4-type RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 4566495   100 DSKCPICLDR-FDNVSYldRCLHK-FCFRCVQEWSKNKAECPLCKQP 144
Cdd:cd16647    1 GSECVICYERpVDTVLY--RCGHMcMCYDCALQLKRRGGSCPICRAP 45

RING finger, HC subclass, found in mind bomb MIB1, MIB2, RGLG1, RGLG2, and similar proteins; MIBs are large, multi-domain E3 ubiquitin-protein ligases that promote ubiquitination of the cytoplasmic tails of Notch ligands. They are also responsible for TBK1 K63-linked ubiquitination and activation, promoting interferon production and controlling antiviral immunity. Moreover, MIBs selectively control responses to cytosolic RNA and regulate type I interferon transcription. Both MIB1 and MIB2 have similar domain architectures, which consist of two Mib-Herc2 domains flanking a ZZ zinc finger, a REP region including two tandem Mib repeats, an ANK region that spans ankyrin repeats, and a RNG region, where MIB1 and MIB2 contain three and two C3HC4-type RING-HC fingers, respectively. This model corresponds to the third RING-HC finger of MIB1, as well as the second RING-HC finger of MIB2. In addition to MIB1 and MIB2, the RING-HC fingers of RING domain ligase RGLG1, RGLG2 and similar proteins from plant are also included in this model. RGLG1 is a ubiquitously expressed E3 ubiquitin-protein ligase that interacts with UBC13 and, together with UBC13, catalyzes the formation of K63-linked polyubiquitin chains, which is involved in DNA damage repair. RGLG1 mediates the formation of canonical, K48-linked polyubiquitin chains that target proteins for degradation. It also regulates apical dominance by acting on the auxin transport proteins abundance. RGLG1 has overlapping functions with its closest sequelog, RGLG2. They both function as RING E3 ligases that interact with ethylene response factor 53 (ERF53) in the nucleus and negatively regulate the plant drought stress response. All RGLG proteins contain a Von Willebrand factor type A (vWA) domain and a C3HC4-type RING-HC finger.

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gi 4566495   103 CPICLDRFDNVSYLdrCLHKFCFRCvqewSKNKAECPLCKQP 144
Cdd:cd16520    3 CPICMERKKNVVFL--CGHGTCQKC----AEKLKKCPICRKP 38

RING finger, H2 subclass, found in rice E3 ubiquitin-protein ligase EL5 and similar proteins; EL5, also known as protein ELICITOR 5, is an E3 ubiquitin-protein ligase containing an N-terminal transmembrane domain and a C3H2C3-type RING-H2 finger that is a binding site for ubiquitin-conjugating enzyme (E2). It can be rapidly induced by N-acetylchitooligosaccharide elicitor. EL5 catalyzes polyubiquitination via the Lys48 residue of ubiquitin, and thus plays a crucial role as a membrane-anchored E3 in the maintenance of cell viability after the initiation of root primordial formation in rice. It also acts as an anti-cell death enzyme that might be responsible for mediating the degradation of cytotoxic proteins produced in root cells after the actions of phytohormones. Moreover, EL5 interacts with UBC5b, a rice ubiquitin carrier protein, through its RING-H2 finger. EL5 is an unstable protein, and its degradation is regulated by the C3H2C3-type RING-H2 finger in a proteasome-independent manner.

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gi 4566495   103 CPICLDRF---DNVSYLDRCLHKFCFRCVQEWSKNKAECPLC 141
Cdd:cd16461    2 CAICLSDYengEELRRLPECKHAFHKECIDEWLKSNSTCPLC 43

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 4566495   102 KCPICLDRFDNVSYLDrCLHKFCF-----RCVQEWSKnKAECPLCK 142
Cdd:cd16524    7 TCPICLDRYRRPKLLP-CQHTFCLspcleGLVDYVTR-KLKCPECR 50