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 334185791 157 EECGICMEMNNMVVLPnCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16545    1 EECCICMDRKADLILP-CAHSYCQKCIDKWSDRHRTCPICR 40

RING finger, HC subclass, found in RING finger protein 141 (RNF141) and similar proteins; RNF141, also known as zinc finger protein 230 (ZNF230), is a RING finger protein present primarily in the nuclei of spermatogonia, the acrosome, and the tail of spermatozoa. It may have a broad function during early development of vertebrates. It plays an important role in spermatogenesis, including spermatogenic cell proliferation and sperm maturation, as well as motility and fertilization. It also exhibits DNA binding activity. RNF141/ZNF230 gene mutations may be associated with azoospermia. RNF141 contains a C3HC4-type RING finger domain that may function as an activator module in transcription.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 334185791 157 EECGICMEMNNMVVLPnCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16545    1 EECCICMDRKADLILP-CAHSYCQKCIDKWSDRHRTCPICR 40

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 334185791  158 ECGICMEM---NNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:pfam13639   2 ECPICLEEfeeGDKVVVLPCGHHFHRECLDKWLRSSNTCPLCR 44

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 334185791 159 CGICMEMNNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR----DSLKRVNSGDLWML 211
Cdd:COG5432   28 CRICDCRISIPCETTCGHTFCSLCIRRHLGTQPFCPVCRedpcESRLRGSSGSREIN 84

RING finger, HC subclass, found in RING finger protein 141 (RNF141) and similar proteins; RNF141, also known as zinc finger protein 230 (ZNF230), is a RING finger protein present primarily in the nuclei of spermatogonia, the acrosome, and the tail of spermatozoa. It may have a broad function during early development of vertebrates. It plays an important role in spermatogenesis, including spermatogenic cell proliferation and sperm maturation, as well as motility and fertilization. It also exhibits DNA binding activity. RNF141/ZNF230 gene mutations may be associated with azoospermia. RNF141 contains a C3HC4-type RING finger domain that may function as an activator module in transcription.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 334185791 157 EECGICMEMNNMVVLPnCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16545    1 EECCICMDRKADLILP-CAHSYCQKCIDKWSDRHRTCPICR 40

N1R/p28-like protein; Provisional

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 334185791 152 DIEREEECGICME------MNNMV--VLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:PHA02929 170 NRSKDKECAICMEkvydkeIKNMYfgILSNCNHVFCIECIDIWKKEKNTCPVCR 223

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 334185791 157 EECGICMEMNNMVVLPNCTHSLCIKCYRDW-HGRSESCPFC 196
Cdd:cd16449    1 LECPICLERLKDPVLLPCGHVFCRECIRRLlESGSIKCPIC 41

RING finger, HC subclass, found in makorin-1 (MKRN1), makorin-3 (MKRN3), and similar proteins; MKRN1, also known as makorin RING finger protein 1 or RING finger protein 61 (RNF61), is an E3 ubiquitin-protein ligase targeting the telomerase catalytic subunit (TERT) for proteasome processing. It regulates the ubiquitination and degradation of peroxisome-proliferator-activated receptor gamma (PPARgamma), a nuclear receptor that is linked to obesity and metabolic diseases. It also mediates the posttranslational regulation of p14ARF, and thus potentially regulates cellular senescence and tumorigenesis in gastric cancer. Moreover, MKRN1 functions as a differentially negative regulator of p53 and p21, and controls cell cycle arrest and apoptosis. It induces degradation of West Nile virus (WNV) capsid protein to protect cells from WNV. It is a RNA-binding protein involved in the modulation of cellular stress and apoptosis. It predominantly associates with proteins involved in mRNA metabolism including regulators of mRNA turnover, transport, and/or translation, and acts as a component of a ribonucleoprotein complex in embryonic stem cells (ESCs) that is recruited to stress granules upon exposure to environmental stress. MKRN1 interacts with poly(A)-binding protein (PABP), a key component of different ribonucleoprotein complexes, in an RNA-independent manner, and stimulates translation in nerve cells. In addition, MKRN1 is a novel SEREX (serological identification of antigens by recombinant cDNA expression cloning) antigen of esophageal squamous cell carcinoma (SCC). It may be involved in carcinogenesis of the well-differentiated type of tumors possibly via ubiquitination of filamin A interacting protein 1 (L-FILIP). Human MKRN1 contains three N-terminal C3H1-type zinc fingers, a motif rich in Cys and His residues (CH), a C3HC4-type RING-HC finger, and another C3H1-type zinc finger at the C-terminus. MKRN3, also known as makorin RING finger protein 3, RING finger protein 63 (RNF63), or zinc finger protein 127 (ZNF127), is a therian mammal-specific retrocopy of MKRN1. It acts as a putative E3 ubiquitin-protein ligase involved in ubiquitination and cell signaling. MKRN3 shows a potential inhibitory effect on hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Its defects represent the most frequent known genetic cause of familial central precocious puberty (CPP). In contrast to human MKRN1, human MKRN3 lacks the second C3H1-type zinc finger at the N-terminal region. The RING-HC finger of mammalian MKRN4 shows high sequence similarity with that of MKRN3, and is also included in this model.

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                 ....*....|....*....|....*....|....*....|....*....|....*
gi 334185791 159 CGICMEM---------NNMVVLPNCTHSLCIKCYRDWHGRSE-------SCPFCR 197
Cdd:cd16730    4 CGICMEVvyekanpseRRFGILSNCNHTYCLKCIRKWRSAKQfeskiikSCPECR 58

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 334185791  158 ECGICMEM---NNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:pfam13639   2 ECPICLEEfeeGDKVVVLPCGHHFHRECLDKWLRSSNTCPLCR 44

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 334185791 156 EEECGICMEM--NNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16574    1 DSSCPICLDRfeNEKAFLDGCFHAFCFTCILEWSKVKNECPLCK 44

zinc finger-like protein; Provisional

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 334185791 153 IEREEECGICMEM---------NNMVVLPNCTHSLCIKCYRDWH------GRSESCPFCRDSLKRVNSGDLWMLM 212
Cdd:PHA02926 167 VSKEKECGICYEVvyskrlendRYFGLLDSCNHIFCITCINIWHrtrretGASDNCPICRTRFRNITMSKFYKLV 241

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 334185791 152 DIEREEECGICMEM-NNMVVLPnCTHSLCIKC----YRDWHGRSESCPFCRDSLKR 202
Cdd:cd16597    1 DLEEELTCSICLELfKDPVTLP-CGHNFCGVCiektWDSQHGSEYSCPQCRATFPR 55

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 334185791  155 REEECGICMEMN-NMVVLPnCTH-SLCIKCYRDWHGRSESCPFCR 197
Cdd:pfam13920   1 EDLLCVICLDRPrNVVLLP-CGHlCLCEECAERLLRKKKKCPICR 44

RING finger, HC subclass, found in makorin-4 (MKRN4) and similar proteins; MKRN4, also known as makorin RING finger protein pseudogene 4, makorin RING finger protein pseudogene 5, RING finger protein 64 (RNF64), zinc finger protein 127-Xp (ZNF127-Xp), or zinc finger protein 127-like 1, is a new divergent member of the makorin protein family in vertebrates. It may have an ancestral gonad-specific function and maternal embryonic expression before duplication in vertebrates. MKRN4 contains typical arrays of one to four C3H1-type zinc fingers, a motif rich in Cys and His residues (CH) and a C3HC4-type RING-HC finger. The RING-HC finger of mammalian MKRN4 shows high sequence similarity with that of MKRN3, and is not included in this model.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 334185791 159 CGICMEM---------NNMVVLPNCTHSLCIKCYRDWHGRSE-------SCPFCR 197
Cdd:cd16732    4 CGICMDKvyekahakeRVFGILPNCNHAFCVGCIKKWRKSKDfqnevikACPQCR 58

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        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 334185791 159 CGICME-MNNMVVLPNCTHSLCIKCYRDWHGRSESCPFCRdslKRVNSGDL 208
Cdd:cd16529    7 CPICFEyFNTAMMITQCSHNYCSLCIRRFLSYKTQCPTCR---AAVTESDL 54

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 334185791 158 ECGICMEMNNMVVLPNCTHSLCIKCYRDW-HGRSESCPFCR 197
Cdd:cd23138    4 NCSFCMQLPERPVTTPCGHNFCLKCFQKWmGQGKKTCGTCR 44

Modified RING finger, HC subclass (C4C4-type), found in HOIL-1-interacting protein (HOIP) and similar proteins; HOIP, also known as RING finger protein 31 (RNF31) or zinc in-between-RING-finger ubiquitin-associated domain protein, together with HOIL-1 and SHARPIN, forms the E3-ligase complex (also known as linear-ubiquitin-chain assembly complex LUBAC) that regulates NF-kappaB activity and apoptosis. It also interacts with the atypical mammalian orphan receptor DAX-1, trigger DAX-1 ubiquitination and stabilization, and participate in repressing steroidogenic gene expression. HOIP contains three Npl4 zinc fingers, a central ubiquitin-associated (UBA) domain responsible for the interaction with the N-terminal ubiquitin-like domain (UBL) of HOIL-1L, an RBR domain, and a C-terminal linear chain determining domain (LDD). The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been corrected as RING-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR (RING1-BRcat-Rcat) domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase function to facilitate the ubiquitination reaction. This model corresponds to the RING domain, a C4C4-type RING finger motif whose overall folding is similar to that of the C3HC4-type RING-HC finger. It is required for RBR-mediated ubiquitination.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 334185791 158 ECGICME---MNNMVVLPNCTHSLCIKCYR--------DWHGRSESCPFC 196
Cdd:cd16631    2 ECPICFNsfpRNKMVSLTSCECKICPDCFKqyftvvikEKHIRDLVCPAC 51

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 334185791 158 ECGICM---EMNNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16467    1 ECTICLgeyETGEKLRRLPCSHEFHSECVDRWLKENSSCPICR 43

RING finger, HC subclass, found in muscle-specific RING finger protein 3 (MuRF-3) and similar proteins; MuRF-3, also known as tripartite motif-containing protein 54 (TRIM54), or RING finger protein 30 (RNF30), is an E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover. It is ubiquitously detected in all fibre types, is developmentally upregulated, associates with microtubules, the sarcomeric M-line and Z-line, and is required for microtubule stability and myogenesis. It associates with glutamylated microtubules during skeletal muscle development, and is required for skeletal myoblast differentiation and development of cellular microtubular networks. MuRF-3 controls the degradation of four-and-a-half LIM domain (FHL2) and gamma-filamin and is required for maintenance of ventricular integrity after myocardial infarction (MI). MuRF-3 belongs to the C-II 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 COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 334185791 159 CGICMEM--NNMVVLPnCTHSLCIKCYRD--------WHGRSES---------CPFCR 197
Cdd:cd16761    3 CPICLEMftKPVVILP-CQHNLCRKCANDvfqasnplWQSRGSStvssggrfrCPSCR 59

Zinc finger, C3HC4 type (RING finger);

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 334185791  158 ECGICMEM--NNMVVLPnCTHSLCIKCYRDWHGRSESCPFC 196
Cdd:pfam13923   1 MCPICMDMlkDPSTTTP-CGHVFCQDCILRALEASNECPLC 40

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 334185791 153 IEREEECGICMEMNNMVVLPNCTHSLCIKCYRDWHGRSES-----CPFCRDSLKRVNSGDLWML 211
Cdd:cd16598    1 LEEEVTCSICLDYLRDPVTIDCGHNFCRSCITDYCPISGGherpvCPLCRKPFKKENIRPNWQL 64

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
                 ....*....|....*....|....*....|....*....|....*...
gi 334185791 156 EEECGICMEM---NNMVVLPNCTHSLCIKCYRDWHGRSESCPFCRDSL 200
Cdd:cd23122   11 EDACSICLESfceADPATVTSCKHEYHLQCILEWSQRSKECPMCWQAL 58

RING finger, H2 subclass, found in RING finger protein 11 (RNF11) and similar proteins; RNF11 is an E3 ubiquitin-protein ligase that acts both as an adaptor and a modulator of itch-mediated control of ubiquitination events underlying membrane traffic. It acts downstream of an enzymatic cascade for the ubiquitination of specific substrates. It is also a molecular adaptor of homologous to E6-associated protein C-terminus (HECT)-type ligases. RNF11 has been implicated in the regulation of several signaling pathways. It enhances transforming growth factor receptor (TGFR) signaling by both abrogating Smurf2-mediated receptor ubiquitination and by promoting the Smurf2-mediated degradation of AMSH (associated molecule with the SH3 domain of STAM), a de-ubiquitinating enzyme that enhances TGF-beta signaling and epidermal growth factor receptor (EGFR) endosomal recycling. It also acts directly on Smad4 to enhance Smad4 function, and plays a role in prolonged TGF-beta signaling. RNF11 also functions as a critical component of the A20 ubiquitin-editing protein complex that negatively regulates tumor necrosis factor (TNF)-mediated nuclear factor (NF)-kappaB activation. It interacts with Smad anchor for receptor activation (SARA) and the endosomal sorting complex required for transport (ESCRT)-0 complex, thus participating in the regulation of lysosomal degradation of EGFR. RNF11 acts as a novel GGA cargo actively participating in regulating the ubiquitination of the GGA protein family. RNF11 functions together with TAX1BP1 to target TANK-binding kinase 1 (TBK1)/IkappaB kinase IKKi, and further restricts antiviral signaling and type I interferon (IFN)-beta production. RNF11 contains an N-terminal PPPY motif that binds WW domain-containing proteins such as AIP4/itch, Nedd4 and Smurf1/2 (SMAD-specific E3 ubiquitin-protein ligase 1/2), and a C-terminal C3H2C3-type RING-H2 finger that functions as a scaffold for the coordinated transfer of ubiquitin to substrate proteins together with the E2 enzymes UbcH527 and Ubc13.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 334185791 158 ECGICME---MNNMV-VLPnCTHSLCIKCYRDWHGRSESCPFC 196
Cdd:cd16468    1 ECVICMAdfvVGDPIrYLP-CMHIYHVDCIDDWLMRSFTCPSC 42

RING finger, H2 subclass, found in Saccharomyces cerevisiae alcohol-sensitive RING finger protein 1 (ASR1) and similar proteins; ASR1 is required for tolerance to alcohol. It signals alcohol stress to the nucleus. ASR1 contains a C3H2C3-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 334185791 157 EECGICMEMNNMVV--LPNCTHSLCIKCYRDWHGRS--ESCPFCR 197
Cdd:cd23120    2 EECPICLEEMNSGTgyLADCGHEFHLTCIREWHNKSgnLDCPICR 46

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Cbl-b and similar proteins; Cbl-b, also known as Casitas B-lineage lymphoma proto-oncogene b, RING finger protein 56 (RNF56), SH3-binding protein Cbl-b, or signal transduction protein Cbl-b, has been identified as a regulator of antigen-specific, T cell-intrinsic, peripheral immune tolerance, a state also known as clonal anergy. It may inhibit activation of the p85 subunit of phosphoinositide 3-kinase (PI3K), protein kinase C-theta (PKC-theta), and phospholipase C-gamma1 (PLC-gamma1) and negatively regulates T-cell receptor-induced transcription factor nuclear factor kappaB (NF-kappaB) activation. In addition, Cbl-b may target multiple signaling molecules involved in transforming growth factor (TGF)-beta-mediated transactivation pathways. Cbl-b contains a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, is composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain), a proline rich domain, a nuclear localization signal, a C3HC4-type RING-HC finger and an ubiquitin-associated (UBA) domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 334185791 159 CGICMEMNNMVVLPNCTHSLCIKCYRDWH-GRSESCPFCRDSLK 201
Cdd:cd16709   23 CKICAENDKDVKIEPCGHLMCTSCLTAWQeSDGQGCPFCRCEIK 66

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
                 ....*....|....*....|....*....|....*....|....
gi 334185791 154 EREEECGICMEMNNMVVLPNCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16741   12 EADDICAICQAEFRKPILLICQHVFCEECISLWFNREKTCPLCR 55

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 334185791 157 EECGICM-EMNNMVVLPNCTHSLCIKCYRDWHGRSESCPFCRDSL 200
Cdd:cd16506    1 DTCPICLdEIQNKKTLEKCKHSFCEDCIDRALQVKPVCPVCGVVY 45

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 334185791 159 CGICMEM---NNMVVLPNCTHSLCIKCYRDW-HGRSESCPFCR 197
Cdd:cd16448    1 CVICLEEfeeGDVVRLLPCGHVFHLACILRWlESGNNTCPLCR 43

RING finger, HC subclass, found in RING finger and transmembrane domain-containing protein RNFT1, RNFT2, and similar proteins; Both RNFT1 and RNFT2 are multi-pass membrane proteins containing a C3HC4-type RING-HC finger. Their biological roles remain unclear.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 334185791 159 CGICME-MNNMVVLPnCTHSLCIKCYRDWHGRSESCPFCR 197
Cdd:cd16532    3 CPICQDeFKDPVVLR-CKHIFCEDCVSEWFERERTCPLCR 41

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 334185791 106 FYAVIFPS----LLQLERGITDLDD--RKQKEVCKIRYRNKD--ETEKVKLSEIDIEREEECGICME----------MNN 167
Cdd:COG5243  229 LFMYQFPYvrvpIYLIRQMYTCFYAlfRRIREHARFRRATKDlnAMYPTATEEQLTNSDRTCTICMDemfhpdheplPRG 308

                         90       100       110
                 ....*....|....*....|....*....|....*.
gi 334185791 168 MVVLPN---CTHSLCIKCYRDWHGRSESCPFCRDSL 200
Cdd:COG5243  309 LDMTPKrlpCGHILHLHCLKNWLERQQTCPICRRPV 344

RING finger, HC subclass, found in RING finger protein 170 (RNF170) and similar proteins; RNF170, also known as putative LAG1-interacting protein, is an endoplasmic reticulum (ER) membrane-bound E3 ubiquitin-protein ligase that mediates ubiquitination-dependent degradation of type-I inositol 1,4,5-trisphosphate (IP3) receptors (ITPR1) via the endoplasmic-reticulum-associated protein degradation (ERAD) pathway. A point mutation (arginine to cysteine at position 199) in the RNF170 gene is linked with autosomal-dominant sensory ataxia (ADSA), a disease characterized by neurodegeneration in the posterior columns of the spinal cord. RNF170 contains a C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 334185791 157 EECGICMEMNNMVVLPNCTHSLCIKC------YRDWHGRSeSCPFCR 197
Cdd:cd16553    2 MECPICLQDARFPVETNCGHLFCGPCiitywrHGSWLGAV-SCPVCR 47

RING finger, HC subclass, found in bifunctional apoptosis regulator (BAR); BAR, also known as RING finger protein 47, was originally identified as an inhibitor of Bax-induced apoptosis. It participates in the block of apoptosis induced by TNF-family death receptors (extrinsic pathway) and mitochondria-dependent apoptosis (intrinsic pathway). BAR is predominantly expressed by neurons in the central nervous system and is involved in the regulation of neuronal survival. It is an endoplasmic reticulum (ER)-associated RING-type E3 ubiquitin ligase that interacts with BI-1 protein and post-translationally regulates its stability, as well as functioning in ER stress. BAR contains an N-terminal C3HC4-type RING-HC finger, a SAM domain, a coiled-coil domain, and a C-terminal transmembrane (TM) domain. This model corresponds to the RING-HC finger responsible for the binding of ubiquitin conjugating enzymes (E2s).

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 334185791 159 CGICMEMNNMVVLPNCTHSLCIKC-YRDWH-GRSESCPFCRDS 199
Cdd:cd16497    4 CHCCYDLLVNPTTLNCGHSFCRHClALWWKsSKKTECPECRQK 46

Modified RING finger, HC subclass (C3HC3D-type), found in Caenorhabditis elegans putative GTP-binding protein trim-23 homolog (arc-1) and similar proteins; arc-1, also called RING-type E3 ubiquitin transferase arc-1, is an E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. arc-1 contains a modified C3HC3D-type RING-HC finger.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 334185791 156 EEECGICM-EMNNMV------VLPNCTHSLCIKCYRDWHGRSES---CPFCR 197
Cdd:cd23124    1 ELECGICQqEYSADDplliprILTECGHTICTNCAGTILGQSSGsifCPFDR 52

RING finger, HC subclass, found in muscle-specific RING finger protein 2 (MuRF-2) and similar proteins; MuRF-2, also known as tripartite motif-containing protein 55 (TRIM55) or RING finger protein 29 (RNF29), is a muscle-specific E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover and is also a ligand of the transactivation domain of the serum response transcription factor (SRF). It is predominantly slow-fibre associated and highly expressed in embryonic skeletal muscle. MuRF-2 associates transiently with microtubules, myosin, and titin during sarcomere assembly. It has been implicated in microtubule, intermediate filament, and sarcomeric M-line maintenance in striated muscle development, as well as in signaling from the sarcomere to the nucleus. It plays an important role in the earliest stages of skeletal muscle differentiation and myofibrillogenesis. It is developmentally downregulated and is assembled at the M-line region of the sarcomere and with microtubules. MuRF-2 belongs to the C-II 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 COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.

                         10        20        30
                 ....*....|....*....|....*....|....
gi 334185791 154 EREEECGICMEM--NNMVVLPnCTHSLCIKCYRD 185
Cdd:cd16760    1 EKQLICPICLEMftKPVVILP-CQHNLCRKCAND 33

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 334185791 158 ECGICME-MNNMVVLPNCTHSLCIKCYRD-WHGRSESCPFCRD 198
Cdd:cd16544    4 TCPVCQEvLKDPVELPPCRHIFCKACILLaLRSSGARCPLCRG 46

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM5, TRIM6, TRIM22, TRIM34 and similar proteins; TRIM5, TRIM6, TRIM22, and TRIM34, four 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, 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. TRIM5, also known as RING finger protein 88 (RNF88), is a capsid-specific restriction factor that prevents infection from non-host-adapted retroviruses in a species-specific manner by binding to and destabilizing the retroviral capsid lattice before reverse transcription is completed. Its retroviral restriction activity correlates with the ability to activate TAK1-dependent innate immune signaling. TRIM5 also acts as a pattern recognition receptor that activates innate immune signaling in response to the retroviral capsid lattice. Moreover, TRIM5 plays a role in regulating autophagy through activation of autophagy regulator BECN1 by causing its dissociation from its inhibitors BCL2 and TAB2. It also plays a role in autophagy by acting as a selective autophagy receptor which recognizes and targets HIV-1 capsid protein p24 for autophagic destruction. TRIM6, also known as RING finger protein 89 (RNF89), is an E3-ubiquitin ligase that cooperates with the E2-ubiquitin conjugase UbE2K to catalyze the synthesis of unanchored K48-linked polyubiquitin chains, and further stimulates the interferon-I kappa B kinase epsilon (IKKepsilon) kinase-mediated antiviral response. It also regulates the transcriptional activity of Myc during the maintenance of embryonic stem (ES) cell pluripotency, and may act as a novel regulator for Myc-mediated transcription in ES cells. TRIM22, also known as 50 kDa-stimulated trans-acting factor (Staf-50) or RING finger protein 94 (RNF94), is an E3 ubiquitin-protein ligase that plays an integral role in the host innate immune response to viruses. It has been shown to inhibit the replication of a number of viruses, including HIV-1, hepatitis B, and influenza A. TRIM22 acts as a suppressor of basal HIV-1 long terminal repeat (LTR)-driven transcription by preventing the transcription factor specificity protein 1 (Sp1) binding to the HIV-1 promoter. It also controls FoxO4 activity and cell survival by directing Toll-like receptor 3 (TLR3)-stimulated cells toward type I interferon (IFN) type I gene induction or apoptosis. Moreover, TRIM22 can activate the noncanonical nuclear factor-kappaB (NF-kappaB) pathway by activating I kappa B kinase alpha (IKKalpha). It also regulates nucleotide binding oligomerization domain containing 2 (NOD2)-dependent activation of interferon-beta signaling and nuclear factor-kappaB. TRIM34, also known as interferon-responsive finger protein 1 or RING finger protein 21 (RNF21), may function as antiviral protein that contribute to the defense against retroviral infections.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 334185791 151 IDIEREEECGICMEMNNMVVLPNCTHSLCIKCYRDWHGRS------ESCPFCRDS 199
Cdd:cd16591    1 VNIKEEVTCPICLELLTEPLSLDCGHSFCQACITANHKESvnqegeSSCPVCRTS 55

RING finger, HC subclass, found in tripartite motif-containing proteins TRIM9, TRIM67, and similar proteins; Tripartite motif-containing proteins TRIM9 and TRIM67 belong to the C-I subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, consisting of three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, a fibronectin type III (FN3) domain, and a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. TRIM9 (the human ortholog of rat Spring), also known as RING finger protein 91 (RNF91), is a brain-specific E3 ubiquitin-protein ligase collaborating with an E2 ubiquitin conjugating enzyme UBCH5b. TRIM9 plays an important role in the regulation of neuronal functions and participates in neurodegenerative disorders through its ligase activity. TRIM67, also known as TRIM9-like protein (TNL), is a protein selectively expressed in the cerebellum. It interacts with PRG-1, an important molecule in the control of hippocampal excitability dependent on presynaptic LPA2 receptor signaling, and 80K-H, also known as glucosidase II beta, a protein kinase C substrate.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 334185791 154 EREEECGICMEM-NNMVVLPnCTHSLCIKCYRDwhgRSESCPFCR 197
Cdd:cd16576    1 EEELKCPVCGSLfTEPVILP-CSHNLCLGCALN---IQLTCPICH 41

RING finger, HC subclass, found in makorin-2 (MKRN2) and similar proteins; MKRN2, also known as makorin RING finger protein 2, RING finger protein 62 (RNF62), or HSPC070, is a putative ribonucleoprotein that acts as a neurogenesis inhibitor acting upstream of glycogen synthase kinase-3beta (GSK-3beta) in the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. It also functions in promoting cell proliferation of primary CD34+ progenitor cells and K562 cells, indicating its possible involvement in normal and malignant hematopoiesis. Mammalian MKRN2 contains three N-terminal C3H1-type zinc fingers, a motif rich in Cys and His residues (CH), a C3HC4-type RING-HC finger, and another C3H1-type zinc finger at the C-terminus. The third C3H1-type zinc finger, the CH motif, as well as the RING zinc finger are necessary for its anti-neurogenic activity.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 334185791 159 CGICMEM---------NNMVVLPNCTHSLCIKCYRDWHGRSE-------SCPFCR 197
Cdd:cd16731    4 CSICMEVvyekasaseRRFGILSNCNHTYCLSCIRQWRCAKQfenpiikSCPECR 58

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 334185791 155 REEECGICMEMNNMVVLPNCTHSLCIKC-YRDWHGRSES-CPFCRD 198
Cdd:cd23132    1 EEFLCCICLDLLYKPVVLECGHVFCFWCvHRCMNGYDEShCPLCRR 46

RING finger, HC subclass, found in protein Deltex-3-like (DTX3L) and similar proteins; DTX3L, also known as B-lymphoma- and BAL-associated protein (BBAP) or Rhysin-2 (Rhysin2), is a RING-domain E3 ubiquitin-protein ligase that 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. DTX3L has a unique N-terminus, but lacks the highly basic N-terminal motif and the central proline-rich motif present in other Deltex (DTX) family members, such as DTX1, DTX2, and DTX4. Moreover, its C-terminal region is highly homologous to DTX3. It includes a C3HC4-type RING-HC finger, and a previously unidentified C-terminal domain. DTX3L can associate with DTX1 through its unique N-terminus and further enhance self-ubiquitination.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 334185791 156 EEECGICME-MNNMVVLPNCTHSLCIKCYRDWHGRSESCPFC 196
Cdd:cd16712    3 EDECPICMDrISNKKVLPKCKHVFCAACIDKAMKYKPVCPVC 44