Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:pfam13639   1 DECPICLEEFEEGDKVVVLPCGHHFHRECLDKWLRSSNTCPLC 43

N1R/p28-like protein; Provisional

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1063724444  88 LTDFElkKQYREAID-ECPICLE---EYEIDNP--KLLTKCGHDFHLACILAWMERSEACPVCDKELV 149
Cdd:PHA02929  162 LSEYE--KLYNRSKDkECAICMEkvyDKEIKNMyfGILSNCNHVFCIECIDIWKKEKNTCPVCRTPFI 227

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 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWME-RSEACPVC 144
Cdd:cd16448     1 CVICLEEFEEGDVVRLLPCGHVFHLACILRWLEsGNNTCPLC 42

RING finger, H2 subclass, found in Arabidopsis thaliana RING-H2 zinc finger protein RHF2A and similar proteins; RHF2A is an E3 ubiquitin-protein ligase involved in the positive regulation of the gametogenesis progression. It is required for the degradation of KRP6, a cyclin-dependent kinase inhibitor which accumulates during meiosis and blocks the progression of subsequent mitoses during gametophytes development. It functions in association with RHF1A. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVCDKELVLTE 152
Cdd:cd23122    12 DACSICLESFCEADPATVTSCKHEYHLQCILEWSQRSKECPMCWQALSLKD 62

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:pfam13639   1 DECPICLEEFEEGDKVVVLPCGHHFHRECLDKWLRSSNTCPLC 43

RING finger, H2 subclass, found in RING finger protein 103 (RNF103) and similar proteins; RNF103, also known as KF-1 or zinc finger protein 103 homolog (Zfp-103), is an endoplasmic reticulum (ER)-resident E3 ubiquitin-protein ligase that is widely expressed in many different organs, including brain, heart, kidney, spleen, and lung. It is involved in the ER-associated degradation (ERAD) pathway by interacting with components of the ERAD pathway, including Derlin-1 and VCP. RNF103 contains several hydrophobic regions at its N-terminal and middle regions, as well as a C-terminal C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMER-SEACPVC 144
Cdd:cd16473     5 EECAICLENYQNGDLLRGLPCGHVFHQNCIDVWLERdNHCCPVC 48

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 1063724444 103 ECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16454     1 TCAICLEEFKEGEKVRVLPCNHLFHKDCIDPWLEQHNTCPLC 42

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

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEE-YEIDN----------PKLLTkCGHDFHLACILAWMERSEACPVCDKELVLTES 153
Cdd:COG5243   290 CTICMDEmFHPDHeplprgldmtPKRLP-CGHILHLHCLKNWLERQQTCPICRRPVIFDQS 349

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 103 ECPICLEEYEI-DNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16461     1 ECAICLSDYENgEELRRLPECKHAFHKECIDEWLKSNSTCPLC 43

RING finger, H2 subclass, found in protein E3 ubiquitin-protein ligase Praja-1, Praja-2, and similar proteins; This family includes two highly similar E3 ubiquitin-protein ligases, Praja-1 and Praja-2. Praja-1, also known as RING finger protein 70, is a RING-H2 finger ubiquitin ligase encoded by gene PJA1, a novel human X chromosome gene abundantly expressed in the brain. It has been implicated in bone and liver development, as well as memory formation and X-linked mental retardation (MRX). Praja-1 interacts with and activates the ubiquitin-conjugating enzyme UbcH5B, and shows E2-dependent E3 ubiquitin ligase activity. It is a 3-deazaneplanocin A (DZNep)-induced ubiquitin ligase that directly ubiquitinates individual polycomb repressive complex 2 (PRC2) subunits in a cell free system, which leads to their proteasomal degradation. It also plays an important role in neuronal plasticity, which is the basis for learning and memory. Moreover, Praja-1 ubiquitinates embryonic liver fodrin (ELF) and Smad3, but not Smad4, in a transforming growth factor-beta (TGF-beta)-dependent manner. It controls ELF abundance through ubiquitin-mediated degradation, and further regulates TGF-beta signaling, which plays a key role in the suppression of gastric carcinoma. Praja-1 also regulates the transcription function of the homeodomain protein Dlx5 by controlling the stability of Dlxin-1, via a ubiquitin-dependent degradation pathway. Praja-2, also known as RING finger protein 131, NEURODAP1, or KIAA0438, is an E2-dependent E3 ubiquitin ligase that interacts with and activates the ubiquitin-conjugating enzyme UbcH5B. It functions as an A-kinase anchoring protein (AKAP)-like E3 ubiquitin ligase that plays a critical role in controlling cyclic AMP (cAMP)-dependent PKA activity and pro-survival signaling, and further promotes cell proliferation and growth. Praja-2 is also involved in protein sorting at the postsynaptic density region of axosomatic synapses and possibly plays a role in synaptic communication and plasticity. Together with the AMPK-related kinase SIK2 and the CDK5 activator CDK5R1/p35, it forms a SIK2-p35-PJA2 complex that plays an essential role for glucose homeostasis in pancreatic beta cell functional compensation. Praja-2 ubiquitylates and degrades Mob, a core component of NDR/LATS kinase and a positive regulator of the tumor-suppressor Hippo signaling. Both Praja-1 and Praja-2 contain a potential nuclear localization signal (NLS) and a C-terminal C3H2C3-type RING-H2 motif.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16465     2 CPICCSEYVKDEIATELPCHHLFHKPCITAWLQKSGTCPVC 42

RING finger, H2 subclass, found in E3 ubiquitin-protein ligase RNF6, RNF12, and similar proteins; RNF6 is an androgen receptor (AR)-associated protein that induces AR ubiquitination and promotes AR transcriptional activity. RNF6-induced ubiquitination may regulate AR transcriptional activity and specificity by modulating cofactor recruitment. RNF6 is overexpressed in hormone-refractory human prostate cancer tissues and required for prostate cancer cell growth under androgen-depleted conditions. RNF6 also regulates local serine/threonine kinase LIM kinase 1 (LIMK1) levels in axonal growth cones. RNF6-induced LIMK1 polyubiquitination is mediated via K48 of ubiquitin and leads to proteasomal degradation of the kinase. RNF6 binds and upregulates the Inha promoter, and functions as a transcription regulatory protein in the mouse sertoli cell. It acts as a potential tumor suppressor gene involved in the pathogenesis of esophageal squamous cell carcinoma (ESCC). RNF12, also known as LIM domain-interacting RING finger protein, or RING finger LIM domain-binding protein (R-LIM), is an E3 ubiquitin-protein ligase encoded by gene RLIM that is crucial for normal embryonic development in some species and for normal X inactivation in mice. It thus functions as a major sex-specific epigenetic regulator of female mouse nurturing tissues. RNF12 is widely expressed during embryogenesis, and mainly localizes to the cell nucleus, where it regulates the levels of many proteins, including CLIM, LMO, HDAC2, TRF1, SMAD7, and REX1, by proteasomal degradation. Both RNF6 and RNF12 contain a well conserved C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1063724444 103 ECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16467     1 ECTICLGEYETGEKLRRLPCSHEFHSECVDRWLKENSSCPIC 42

RING finger, H2 subclass, found in Arabidopsis thaliana RING-type E3 ubiquitin transferase BIG BROTHER (BB) and similar proteins; BB (also known as protein ENHANCER OF DA1-1 or EOD1) is an E3 ubiquitin-protein ligase that limits organ size, and possibly seed size, in a dose-dependent manner. It negatively regulates the duration of cell proliferation in leaves and petals independently of the major phytohormones (e.g. auxin, cytokinin, gibberellin, brassinosteroids, ethylene, abscisic acid, jasmonic acid), probably by targeting growth stimulators for degradation. It limits the proliferation of root meristematic cells. BB polyubiquitinates DA1. It is involved in the promotion of leaf senescence, in addition to its function in restricting plant growth. BB-related is an E3 ubiquitin-ligase probably involved in organ size regulation. Members of this subfamily contain a C3H2C3-type RING-H2 finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1063724444  99 EAIDECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVCDKELV 149
Cdd:cd23115     2 EDNERCVICRLEYEEGEDLLTLPCKHCYHSECIQQWLQINKVCPVCSAEVT 52

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 1063724444 102 DECPICLEEyeIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16506     1 DTCPICLDE--IQNKKTLEKCKHSFCEDCIDRALQVKPVCPVC 41

RING finger, H2 subclass, found in Arabidopsis thaliana MED25-binding RING-H2 protein (MBR) and similar proteins; This subfamily includes MBR1 and MBR2 (also called HAL3-interacting protein 1 or AtHIP1). They are E3 ubiquitin-protein ligases that function as regulators of MED25 stability by targeting MED25 for degradation in a RING-H2-dependent manner. Proteasome-dependent degradation of MED25 seems to activate its function as a positive regulator of FLOWERING LOCUS T (FT) and is important to induce the expression of FT, and consequently to promote flowering. MBR2 may also function downstream of HAL3 and be required for HAL3-regulated plant growth. Activation of MBR2 by HAL3 may lead to the degradation of cell cycle suppressors, resulting in enhancement of cell division and plant growth. Both MBR1 and MBR2 contain a C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1063724444 101 IDECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd23113     2 DEKCCICQEEYEEGDELGTIECGHEYHSDCIKQWLVQKNLCPIC 45

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 1063724444 102 DECPICLEEYEiDNPKLLTkCGHDFHLACILAWMERSEACPVCDKELV 149
Cdd:cd23130     1 DVCPICLDDPE-DEAITLP-CLHQFCYTCILRWLQTSPTCPLCKTPVT 46

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 1063724444 104 CPICLEEYEidNPKLLTKCGHDFHLACILAWME-RSEACPVC 144
Cdd:pfam00097   1 CPICLEEPK--DPVTLLPCGHLFCSKCIRSWLEsGNVTCPLC 40

RING-finger-containing ubiquitin ligase [Posttranslational modification, protein turnover, chaperones];

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1063724444 103 ECPICLEEYEIDNPKLLTKCGHDFHLACILAWM-ERSEACPVCDKEL 148
Cdd:COG5540   325 ECAICMSNFIKNDRLRVLPCDHRFHVGCVDKWLlGYSNKCPVCRTAI 371

RING finger, H2 subclass, found in RING finger protein 167 (RNF167) and similar proteins; RNF167, also known as RING105, is an endosomal/lysosomal E3 ubiquitin-protein ligase involved in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) ubiquitination. It ubiquitinates AMPA-type glutamate receptor subunit GluA2 and regulates its surface expression, and thus acts as a selective regulator of AMPAR-mediated neurotransmission. It acts as an endosomal membrane protein which ubiquitylates vesicle-associated membrane protein 3 (VAMP3) and regulates endosomal trafficking. Moreover, RNF167 plays a role in the regulation of TSSC5 (tumor-suppressing subchromosomal transferable fragment cDNA, also known as ORCTL2/IMPT1/BWR1A/SLC22A1L), which can function in concert with the ubiquitin-conjugating enzyme UbcH6. RNF167 is widely conserved in metazoans and contains an N-terminal signal peptide, a protease-associated (PA) domain, two transmembrane domains (TM1 and TM2), and a C-terminal C3H2C3-type RING-H2 finger domain followed by a putative PEST sequence.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERS-EACPVC 144
Cdd:cd16797     1 DVCAICLDEYEEGDKLRVLPCSHAYHSKCVDPWLTQTkKTCPVC 44

RING finger, H2 subclass, found in RING finger protein 24 (RNF24) 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. RNF24 contains an N-terminal transmembrane domain and a C-terminal C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVCD 145
Cdd:cd16675     3 CAVCLEEFKPKDELGICPCKHAFHRKCLIKWLEVRKVCPLCN 44

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.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1063724444 102 DECPICLEEYEIDN-PKLLTKCGHDFHLACILAWM-ERSEACPVCDKEL 148
Cdd:cd23121     2 DCCAICLSDFNSDEkLRQLPKCGHIFHHHCLDRWIrYNKITCPLCRADL 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 1063724444 102 DECPICLEEyeIDNPK-LLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16574     2 SSCPICLDR--FENEKaFLDGCFHAFCFTCILEWSKVKNECPLC 43

RING finger, H2 subclass, found in RING finger protein 12 (RNF12) and similar proteins; RNF12, also known as LIM domain-interacting RING finger protein or RING finger LIM domain-binding protein (R-LIM), is an E3 ubiquitin-protein ligase encoded by gene RLIM that is crucial for normal embryonic development in some species and for normal X inactivation in mice. It thus functions as a major sex-specific epigenetic regulator of female mouse nurturing tissues. RNF12 is widely expressed during embryogenesis, and mainly localizes to the cell nucleus, where it regulates the levels of many proteins, including CLIM, LMO, HDAC2, TRF1, SMAD7, and REX1, by proteasomal degradation. Its functional activity is regulated by phosphorylation-dependent nucleocytoplasmic shuttling. It is negatively regulated by pluripotency factors in embryonic stem cells. p53 represses its transcription through Sp1. RNF12 is the primary factor responsible for X chromosome inactivation (XCI) in female placental mammals. It is an indispensable factor in up-regulation of Xist transcription, thereby leading to initiation of random XCI. It also targets REX1, an inhibitor of XCI, for proteasomal degradation. RNF12 also acts as a co-regulator for a range of transcription factors, particularly those containing a LIM homeodomain, and modulates the formation of transcriptional multiprotein complexes. It is a negative regulator of Smad7, which in turn negatively regulates the signaling of type I receptors from the transforming growth factor beta (TGF-beta) superfamily. In addition, paternal RNF12 is a critical survival factor for milk-producing alveolar cells. RNF12 contains an nuclear localization signal (NLS) and a C3H2C3-type RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVCDKELV 149
Cdd:cd16674     3 CSVCITEYTEGNKLRKLPCSHEYHVHCIDRWLSENSTCPICRRAVL 48

RING finger, H2 subclass, found in RING finger protein 13 (RNF13) and similar proteins; RNF13 is a widely expressed membrane-associated E3 ubiquitin-protein ligase that is functionally significant in the regulation of cancer development, muscle cell growth, and neuronal development. Its expression is developmentally regulated during myogenesis and is upregulated in various tumors. RNF13 negatively regulates cell proliferation through its E3 ligase activity. It functions as an important regulator of inositol-requiring transmembrane kinase/endonuclease IRE1alpha, mediating endoplasmic reticulum (ER) stress-induced apoptosis through the activation of the IRE1alpha-TRAF2-JNK signaling pathway. Moreover, RNF13 is involved in the regulation of the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) complex via the ubiquitination of snapin, a SNAP25-interacting protein, which thereby controls synaptic function. In addition, RNF13 participates in regulating the function of satellite cells by modulating cytokine composition. RNF13 is evolutionarily conserved among many metazoans and contains an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane (TM) domain and a C-terminal C3H2C3-type RING-H2 finger domain followed by a putative PEST sequence.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERS-EACPVCDKELV 149
Cdd:cd16796     9 DVCAICLDEYEEGDKLRILPCSHAYHCKCVDPWLTKTkKTCPVCKQKVV 57

RING finger, H2 subclass, found in RING finger protein 32 (RNF32) and similar proteins; RNF32 is mainly expressed in testis spermatogenesis, most likely in spermatocytes and/or in spermatids, suggesting a possible role in sperm formation. RNF32 contains two C3H2C3-type RING-H2 fingers separated by an IQ domain of unknown function. Although the biological function of RNF32 remains unclear, proteins with double RING-H2 fingers may act as scaffolds for binding several proteins that function in the same pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1063724444 103 ECPICLEEYEIdNPKLLTKCGHDFHLACILAWMERSE----ACPVC 144
Cdd:cd16471     1 ECPICLCAFKG-RKCTLLSCSHVFHEACLSAFEKFIEsknqKCPLC 45

RING finger, H2 subclass, found in RING finger proteins RNF43, ZNRF3, and similar proteins; RNF43 and ZNRF3 (also known as RNF203) are transmembrane E3 ubiquitin-protein ligases that belong to the PA-TM-RING ubiquitin ligase family, characterized by containing an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane (TM) domain and a C3H2C3-type RING-H2 finger followed by a long C-terminal region. Both RNF43 and RNF203 function as tumor suppressors involved in the regulation of Wnt/beta-catenin signaling. They negatively regulate Wnt signaling by interacting with complexes of frizzled (FZD) receptors and low-density lipoprotein receptor-related protein (LRP) 5/6, which leads to ubiquitination of FZD and endocytosis of the Wnt receptor. Dishevelled (DVL), a positive Wnt regulator, is required for ZNRF3/RNF43-mediated ubiquitination and degradation of FZD. They also associate with R-spondin 1 (RSPO1). This interaction may block FZD ubiquitination and enhances Wnt signaling.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16666     2 CAICLEEYEEGQELRVLPCQHEFHRKCVDPWLLQNHTCPLC 42

RING finger, H2 subclass, found in BRCA1-associated protein (BRAP2) and similar proteins; BRAP2, also known as impedes mitogenic signal propagation (IMP), RING finger protein 52, or renal carcinoma antigen NY-REN-63, is a novel cytoplasmic protein interacting with the two functional nuclear localization signal (NLS) motifs of BRCA1, a nuclear protein linked to breast cancer. It also binds to the SV40 large T antigen NLS motif and the bipartite NLS motif found in mitosin. BRAP2 serves as a cytoplasmic retention protein and plays a role in the regulation of nuclear protein transport. It contains an N-terminal RNA recognition motif (RRM), also known as RBD (RNA binding domain) or RNP (ribonucleoprotein domain), followed by a C3H2C3-type RING-H2 finger and a UBP-type zinc finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1063724444 104 CPICLEEYEIDNPKLLTK-CGHDFHLACILAWMERSeaCPVC 144
Cdd:cd16457     3 CPVCLERMDESVSGILTIlCNHSFHCSCLSKWGDSS--CPVC 42

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 1063724444 102 DECPICLEEyeIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16711     2 ETCPICLGE--IQNKKTLDKCKHSFCEDCITRALQVKKACPMC 42

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
                  ....*....|....*....|....*....|....*....|....*..
gi 1063724444 103 ECPICLEEyeIDNPKLlTKCGHDFHLACILAWMERSEA----CPVCD 145
Cdd:cd16536     2 QCPICLEP--PVAPRI-TRCGHIFCWPCILRYLSLSEKkwrkCPICF 45

first RING finger, H2 subclass, found in RING finger protein 32 (RNF32) and similar proteins; RNF32 is mainly expressed in testis spermatogenesis, most likely in spermatocytes and/or in spermatids, suggesting a possible role in sperm formation. RNF32 contains two C3H2C3-type RING-H2 fingers separated by an IQ domain of unknown function. Although the biological function of RNF32 remains unclear, proteins with double RING-H2 fingers may act as scaffolds for binding several proteins that function in the same pathway. This model corresponds to the first RING-H2 finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1063724444 104 CPICLEEYEIDNPKLLTkCGHDFHLACILAW--MERSEACPVCDKE 147
Cdd:cd16677     2 CPICLEDFGLQQQVLLS-CSHVFHRACLESFerFSGKKTCPMCRKE 46

RING finger, H2 subclass, found in RING finger protein 130 (RNF130) and similar proteins; RNF130, also known as Goliath homolog (H-Goliath), is a paralog of RNF128, also known as gene related to anergy in lymphocytes protein (GRAIL). It is a transmembrane E3 ubiquitin-protein ligase expressed in leukocytes. It has a self-ubiquitination property, and controls the development of T cell clonal anergy by ubiquitination. RNF130 contains an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane (TM) domain and a C-terminal C3H2C3-type RING-H2 finger domain followed by a putative PEST sequence.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16803     1 DHCAVCIEGYKQNDVVRILPCKHVFHKSCVDPWLNEHCTCPMC 43

RING finger, HC subclass, found in Saccharomyces cerevisiae increased recombination centers protein 20 (IRC20) and similar proteins; IRC20 is an uncharacterized ATP-dependent helicase that is probably involved in a pathway contributing to genomic integrity. IRC20 contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEEYEIdnpKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd23135     6 CSICFSEIRS---GAILKCGHFFCLSCIASWLREKSTCPLC 43

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 1063724444 104 CPICLEEY---EIDNPKlltKCGHDFHLACILAWMERSEACPV 143
Cdd:cd16635     7 CPICLNTFrdqAVGTPE---SCDHIFCLDCILEWSKNANTCPV 46

RING finger, H2 subclass, found in RING finger protein 139 (RNF139) and similar proteins; RNF139, also known as translocation in renal carcinoma on chromosome 8 protein (TRC8), is an endoplasmic reticulum (ER)-resident multi-transmembrane protein that functions as a potent growth suppressor in mammalian cells, inducing G2/M arrest, decreased DNA synthesis and increased apoptosis. It is a tumor suppressor that has been implicated in a novel regulatory relationship linking the cholesterol/lipid biosynthetic pathway with cellular growth control. A mutation in RNF139 has been identified in families with hereditary renal (RCC) and thyroid cancers. RNF139 physically and functionally interacts with von Hippel-Lindau (VHL), which is part of an SCF related E3-ubiquitin ligase complex with "gatekeeper" function in renal carcinoma and is defective in most sporadic clear-cell renal cell carcinomas (ccRCC). It suppresses growth and functions with VHL in a common pathway. RNF139 also suppresses tumorigenesis by targeting heme oxygenase-1 for ubiquitination and degradation. Moreover, RNF139 is a target of Translin (TSN), a posttranscriptional regulator of genes transcribed by the transcription factor CREM-tau in postmeiotic male germ cells, suggesting a role of RNF139 in dysgerminoma. In addition, RNF139 forms an integral part of a novel multi-protein ER complex, containing MHC I, US2, and signal peptide peptidase, which is associated with the ER-associated degradation (ERAD) pathway. It is required for the ubiquitination of MHC class I molecules before dislocation from the ER. As a novel sterol-sensing ER membrane protein, RNF139 hinders sterol regulatory element-binding protein-2 (SREBP-2) processing through interaction with SREBP-2 and SREBP cleavage-activated protein (SCAP), regulating its own turnover rate via its E3 ubiquitin ligase activity. RNF139 shows two regions of similarity with the receptor for sonic hedgehog (SHH), Patched. The first region corresponds to the second extracellular domain of Patched, which is involved in binding SHH. The second region is a putative sterol-sensing domain (SSD). The C-terminal half of RNF139 contains a C3H2C3-type RING-H2 finger with E3-ubiquitin ligase activity in vitro.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1063724444  98 REAIDECPICLEEYEidNPKLLTKCGHDFHLACILAWMERSEACPVCDKELVLTE 152
Cdd:cd16683     1 REIDDVCAICYQEFT--TSARITPCNHYFHALCLRKWLYIQDTCPMCHQKVYIED 53

RING finger, H2 subclass, found in RING finger protein 13 (RNF13), RING finger protein 167 (RNF167), and similar proteins; This subfamily includes RING finger protein 13 (RNF13), RING finger protein 167 (RNF167), Zinc/RING finger protein 4 (ZNRF4), and similar proteins, which belong to a larger PA-TM-RING ubiquitin ligase family that has been characterized by containing an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane domain (TM), and a C-terminal C3H2C3-type RING-H2 finger followed by a putative PEST sequence. RNF13 is a widely expressed membrane-associated E3 ubiquitin-protein ligase that functions in the regulation of cancer development, muscle cell growth, and neuronal development. Its expression is developmentally regulated during myogenesis and is upregulated in various tumors. RNF13 negatively regulates cell proliferation through its E3 ligase activity. RNF167, also known as RING105, is an endosomal/lysosomal E3 ubiquitin-protein ligase involved in the ubiquitination of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR). It acts as an endosomal membrane protein which ubiquitylates vesicle-associated membrane protein 3 (VAMP3) and regulates endosomal trafficking. Moreover, RNF167 plays a role in the regulation of TSSC5 (tumor-suppressing subchromosomal transferable fragment cDNA, also known as ORCTL2/IMPT1/BWR1A/SLC22A1L), which can function in concert with the ubiquitin-conjugating enzyme UbcH6. ZNRF4, also known as RING finger protein 204 (RNF204), or Nixin, is an endoplasmic reticulum (ER) membrane-anchored ubiquitin ligase that physically interacts with the ER-localized chaperone calnexin in a glycosylation-independent manner, inducing calnexin ubiquitination, and p97-dependent degradation. The murine protein sperizin (spermatid-specific ring zinc finger) is a homolog of human ZNRF4. It is specifically expressed in Haploid germ cells and is involved in spermatogenesis.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAW-MERSEACPVCDK 146
Cdd:cd16665     1 DVCAICLDDYEEGDKLRILPCSHAYHCKCIDPWlTKNKRTCPVCKR 46

RING finger, HC subclass, found in RING finger and transmembrane domain-containing protein 1 (RNFT1); RNFT1, also known as protein PTD016, is a multi-pass membrane protein containing a C3HC4-type RING-HC finger. Its biological role remains unclear.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1063724444  94 KKQYREAIDECPICLEEYEidNPKLLTkCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16741     7 KRQCSEADDICAICQAEFR--KPILLI-CQHVFCEECISLWFNREKTCPLC 54

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEEYeiDNPKLltKCGHDFHLACILAWMERSEACPVC 144
Cdd:pfam13445   1 CPICLELF--TDPVL--PCGHTFCRECLEEMSQKKGGKFKC 37

Modified RING finger, HC subclass (C3HC3D-type), found in SR-related and CTD-associated factor 11 (SCAF11) and similar proteins; SCAF11, also known as CTD-associated SR protein 11 (CASP11), renal carcinoma antigen NY-REN-40, SC35-interacting protein 1 (Sip1), Serine/arginine-rich splicing factor 2 (SRSF2)-interacting protein, or splicing regulatory protein 129 (SRrp129), is a novel arginine-serine-rich (RS) domain-containing protein essential for pre-mRNA splicing. It functions as an auxiliary splice factor interacting with the spliceosomal component SC35, promoting RNAPII elongation. In addition to SR proteins, such as SC35, ASF/SF2, SRp75, and SRp20, SCAF11 also associates with U1-70K and U2AF65, proteins associated with 5' and 3' splice sites, respectively. SCAF11 contains an N-terminal modified C3HC3D-type RING-HC finger, an internal serine-arginine rich domain (SR domain), and a C-terminal SRI domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1063724444 102 DECPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPV 143
Cdd:cd16636     1 DRCPICLNCLLEQEVAFPENCSHVFCLTCILKWAETVTSCPI 42

RING finger, H2 subclass, found in RING finger proteins, RNF130, RNF149, RNF150 and similar proteins; This subfamily includes RING finger proteins, RNF130, RNF149 and RNF150, which belong to a larger PA-TM-RING ubiquitin ligase family that has been characterized by an N-terminal signal peptide, a protease-associated (PA) domain, a transmembrane (TM) domain and a C-terminal C3H2C3-type RING-H2 finger domain followed by a putative PEST sequence. RNF130, also known as Goliath homolog (H-Goliath), is a paralog of RNF128. It is a transmembrane E3 ubiquitin-protein ligase expressed in leukocytes. It has a self-ubiquitination property and controls the development of T cell clonal anergy by ubiquitination. RNF133 is a testis-specific endoplasmic reticulum-associated E3 ubiquitin ligase that may play a role in sperm maturation through an ER-associated degradation (ERAD) pathway. RNF149, also known as DNA polymerase-transactivated protein 2, is an E3 ubiquitin-protein ligase that induces the ubiquitination of wild-type v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and promotes its proteasome-dependent degradation. RNF150 polymorphisms may be associated with chronic obstructive pulmonary disease (COPD) risk in the Chinese population. This subfamily also includes Drosophila melanogaster protein goliath (d-goliath), also known as protein g1, which is one of the founding members of the group. It was originally identified as a transcription factor involved in the embryo mesoderm formation.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16668     2 CAVCIEPYKPSDVIRILPCKHIFHKSCVDPWLLEHRTCPMC 42

RING finger, H2 subclass, found in RING finger protein 145 (RNF145) and similar proteins; RNF145 is an uncharacterized RING finger protein encoded by the RNF145 gene, which is expressed in T lymphocytes, and its expression is altered in acute myelomonocytic and acute promyelocytic leukemias. Although its biological function remains unclear, RNF145 shows high sequence similarity with RNF139, an endoplasmic reticulum (ER)-resident multi-transmembrane protein that functions as a potent growth suppressor in mammalian cells, inducing G2/M arrest, decreased DNA synthesis and increased apoptosis. Like RNF139, RNF145 contains a C3H2C3-type RING-H2 finger with possible E3-ubiquitin ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 102 DECPICleeYEIDNPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16684     3 DICSIC---YQDMKSAVITPCSHFFHAGCLKKWLYVQETCPLC 42

RING finger, HC subclass, found in RING finger protein 4 (RNF4) and similar proteins; RNF4, also known as small nuclear ring finger protein (SNURF), is a SUMO-targeted E3 ubiquitin-protein ligase with a pivotal function in the DNA damage response (DDR) by interacting with the deubiquitinating enzyme ubiquitin-specific protease 11 (USP11), a known DDR-component, and further facilitating DNA repair. It plays a novel role in preventing the loss of intact chromosomes and ensures the maintenance of chromosome integrity. Moreover, RNF4 is responsible for the UbcH5A-catalyzed formation of K48 chains that target SUMO-modified promyelocytic leukemia (PML) protein for proteasomal degradation in response to arsenic treatment. It also interacts with telomeric repeat binding factor 2 (TRF2) in a small ubiquitin-like modifier (SUMO)-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination through SUMO-interacting motifs (SIMs). Furthermore, RNF4 can form a complex with a Ubc13-ubiquitin conjugate and Ube2V2. It catalyzes K63-linked polyubiquitination by the Ube2V2-Ubc13 (ubiquitin-loaded) complex. Meanwhile, RNF4 negatively regulates nuclear factor kappa B (NF-kappaB) signaling by down-regulating transforming growth factor beta (TGF-beta)-activated kinase 1 (TAK1)-TAK1-binding protein2 (TAB2). RNF4 contains four SIMs followed by a C3HC4-type RING-HC finger at the C-terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1063724444 104 CPICLEEYE--IDNPKLL--TKCGHDFHLACILAWMERSEACPVCDKEL 148
Cdd:cd16533     6 CPICMDGYSeiVQSGRLIvsTECGHVFCSQCLRDSLKNANTCPTCRKKL 54

RING finger, H2 subclass, found in RING finger proteins RNF139, RNF145, and similar proteins; RNF139, also known as translocation in renal carcinoma on chromosome 8 protein (TRC8), is an endoplasmic reticulum (ER)-resident multi-transmembrane protein that functions as a potent growth suppressor in mammalian cells, inducing G2/M arrest, decreased DNA synthesis and increased apoptosis. It is a tumor suppressor that has been implicated in a novel regulatory relationship linking the cholesterol/lipid biosynthetic pathway with cellular growth control. A mutation in RNF139 has been identified in families with hereditary renal (RCC) and thyroid cancers. RNF145 is an uncharacterized RING finger protein encoded by the RNF145 gene, which is expressed in T lymphocytes, and its expression is altered in acute myelomonocytic and acute promyelocytic leukemias. Although its biological function remains unclear, RNF145 shows high sequence similarity with RNF139. Both RNF139 and RNF145 contain a C3H2C3-type RING-H2 finger with possible E3-ubiquitin ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1063724444 102 DECPICLEEYEidnPKLLTKCGHDFHLACILAWMERSEACPVC 144
Cdd:cd16476     1 DVCAICYQEMK---EARITPCNHFFHGLCLRKWLYVQDTCPLC 40

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 1063724444 103 ECPICLEEYEidnPKLLTKCGHDFHLACILAWMERSEA-CPVC 144
Cdd:cd16449     2 ECPICLERLK---DPVLLPCGHVFCRECIRRLLESGSIkCPIC 41

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 1063724444 103 ECPICLEEYEidNPKLLTKCGHDFHLACIL-AWMERSEACPVC 144
Cdd:cd16544     4 TCPVCQEVLK--DPVELPPCRHIFCKACILlALRSSGARCPLC 44

SPL-RING finger found in E3 SUMO-protein ligase NSE2 and similar proteins; NSE2, also known as MMS21 homolog (MMS21) or non-structural maintenance of chromosomes element 2 homolog (Non-SMC element 2 homolog, NSMCE2), is an autosumoylating small ubiquitin-like modifier (SUMO) ligase required for the response to DNA damage. It regulates sumoylation and nuclear-to-cytoplasmic translocation of skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide associated complex (skNAC)-Smyd1 in myogenesis. It is also required for resisting extrinsically induced genotoxic stress. Moreover, NSE2 together with its partner proteins SMC6 and SMC5 form a tight subcomplex of the structural maintenance of chromosomes SMC5-6 complex, which includes another two subcomplexes, NSE1-NSE3-NSE4 and NSE5-NSE6. SMC6 and NSE3 are sumoylated in an NSE2-dependent manner, but SMC5 and NSE1 are not. NSE2-dependent E3 SUMO ligase activity is required for efficient DNA repair, but not for SMC5-6 complex stability. NSE2 contains a RING variant known as a Siz/PIAS (protein inhibitor of activated signal transducer and activator of transcription)-like RING (SPL-RING) finger that is likely shared by the SP-RING type SUMO E3 ligases, such as PIAS family proteins. The SPL-RING finger is a variant of the RING finger, which lacks the second, fifth, and sixth zinc-binding residues of the consensus C3H2C3-/C3HC4-type RING fingers. It harbors only one Zn binding site and is required for the sumoylating activity.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1063724444 104 CPICLEEYEidNPKLLTKCGHDFHLACILAWMERSEA---CPV--CDKELVL 150
Cdd:cd16651     3 CPITQQLMV--DPVRNKKCGHTYEKAAILQYLQSRKKkakCPVagCRNTVSK 52

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 1063724444 103 ECPICLEEyeIDNPkLLTKCGHDFHLACILAWMERSEA---CPVC 144
Cdd:cd16745     2 ECNICLDL--AQDP-VVTLCGHLFCWPCLHKWLRRQSSqpeCPVC 43

Modified RING finger, H2 subclass (C3H2C2D-type), found in zinc finger SWIM domain-containing protein 2 (ZSWIM2) and similar proteins; ZSWIM2, also known as MEKK1-related protein X (MEX) or ZZ-type zinc finger-containing protein 2, is a testis-specific E3 ubiquitin ligase that promotes death receptor-induced apoptosis through Fas, death receptor (DR) 3 and DR4 signaling. ZSWIM2 is self-ubiquitinated and targeted for degradation through the proteasome pathway. It acts as an E3 ubiquitin ligase, through the E2, Ub-conjugating enzymes UbcH5a, UbcH5c, or UbcH6. ZSWIM2 contains four putative zinc-binding domains including an N-terminal SWIM (SWI2/SNF2 and MuDR) domain critical for its ubiquitination, and two modified RING-H2 fingers separated by a ZZ zinc finger domain, which was required for interaction with UbcH5a and its self-association. This model corresponds to the second RING-H2 finger, which is not a canonical C3H2C3-type, but a modified C3H2C2D-type.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1063724444 103 ECPICLEEYEIDNPKLLTKCGHDFHLACILAW-MERSEACPVCDK 146
Cdd:cd16486     1 QCRICLKAFQLGQHVRTLPCRHKFHRDCIDNWlLHSRNSCPIDGQ 45

RING finger, H2 subclass, found in anaphase-promoting complex subunit 11 (APC11) and similar proteins; APC11, also known as cyclosome subunit 11, or hepatocellular carcinoma-associated RING finger protein, is a C3H2C3-type RING-H2 protein that facilitates ubiquitin chain formation by recruiting ubiquitin-charged ubiquitin conjugating enzymes (E2) through its RING-H2 domain. APC11 and its partner, the cullin-like subunit APC2, form the dynamic catalytic core of the gigantic, multisubunit 1.2-MDa anaphase-promoting complex/cyclosome (APC), also known as the cyclosome, which is a ubiquitin-protein ligase (E3) composed of at least 12 subunits and controls cell division by ubiquitinating cell cycle regulators, such as cyclin B and securin, to drive their timely degradation. APC11 can be inhibited by hydrogen peroxide, which may contribute to the delay in cell cycle progression through mitosis that is characteristic of cells subjected to oxidative stress. APC11 contains a canonical RING-H2-finger that coordinate two Zn2+ ions. In addition, it contains a third Zn2+-binding site that is not essential for its ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1063724444 104 CPICLEEYEiDNPKLLTKCGHDFHLACILAWMERSEA---CPVC 144
Cdd:cd16456    15 CPDCKFPGD-DCPLVWGKCSHCFHMHCILKWLNSQQVqqhCPMC 57

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 1063724444 104 CPICLEEYEIDNPKLLTKCGHDFHLACILAWMERS-EACPVC 144
Cdd:cd00162     1 CPICREEMNDRRPVVLLSCGHTFSRSAIARWLEGSkQKCPFC 42