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 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKR 63
Cdd:cd16547    1 DDDLICSICHGVLRCPVRLSCSHIFCKKCILQWLKRQETCPCCRKEVKG 49

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKR 63
Cdd:cd16547    1 DDDLICSICHGVLRCPVRLSCSHIFCKKCILQWLKRQETCPCCRKEVKG 49

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKE 60
Cdd:COG5432   23 DSMLRCRICDCRISIPCETTCGHTFCSLCIRRHLGTQPFCPVCRED 68

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

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 157821155    20 CSVCHGV-LKRPMRLPCSHIFCKKCIFQWL-ARQNTCPCC 57
Cdd:smart00184   1 CPICLEEyLKDPVILPCGHTFCRSCIRKWLeSGNNTCPIC 40

Seven in absentia protein family; The seven in absentia (sina) gene was first identified in Drosophila. The Drosophila Sina protein is essential for the determination of the R7 pathway in photoreceptor cell development: the loss of functional Sina results in the transformation of the R7 precursor cell to a non- neuronal cell type. The Sina protein contains an N-terminal RING finger domain pfam00097. Through this domain, Sina binds E2 ubiquitin-conjugating enzymes (UbcD1) Sina also interacts with Tramtrack (TTK88) via PHYL. Tramtrack is a transcriptional repressor that blocks photoreceptor determination, while PHYL down-regulates the activity of TTK88. In turn, the activity of PHYL requires the activation of the Sevenless receptor tyrosine kinase, a process essential for R7 determination. It is thought that thus Sina targets TTK88 for degradation, therefore promoting the R7 pathway. Murine and human homologs of Sina have also been identified. The human homolog Siah-1 also binds E2 enzymes (UbcH5) and through a series of physical interactions, targets beta-catenin for ubiquitin degradation. Siah-1 expression is enhanced by p53, itself promoted by DNA damage. Thus this pathway links DNA damage to beta-catenin degradation. Sina proteins, therefore, physically interact with a variety of proteins. The N-terminal RING finger domain that binds ubiquitin conjugating enzymes is described in pfam00097, and does not form part of the alignment for this family. The remainder C-terminal part is involved in interactions with other proteins, and is included in this alignment. In addition to the Drosophila protein and mammalian homologs, whose similarity was noted previously, this family also includes putative homologs from Caenorhabditis elegans, Arabidopsis thaliana.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 157821155   79 LQVKCKNAAAGCLVTCPLAHRKGHQDSCPFELMACPNEG--CTAQvlrGVLDEHRQHCQQ 136
Cdd:pfam03145  13 LLFPCKYASSGCSETLPYTEKADHEERCEFRPYSCPCPGssCTWQ---GSLDAVMPHLMD 69

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKR 63
Cdd:cd16547    1 DDDLICSICHGVLRCPVRLSCSHIFCKKCILQWLKRQETCPCCRKEVKG 49

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 157821155  19 LCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16532    2 ICPICQDEFKDPVVLRCKHIFCEDCVSEWFERERTCPLCR 41

RING finger, HC subclass, found in Saccharomyces cerevisiae radiation sensitivity protein 18 (RAD18) and similar proteins; RAD18, also called RING-type E3 ubiquitin transferase RAD18, acts as a postreplication repair E3 ubiquitin-protein ligase that associates with the E2 ubiquitin conjugating enzyme UBC2/RAD6 to form the UBC2-RAD18 ubiquitin ligase complex involved in postreplicative repair (PRR) of damaged DNA. The UBC2-RAD18 complex cooperates with RAD5 and the UBC13-MMS2 dimer to attach mono-ubiquitin chains on 'Lys-164' of POL30, which is necessary for PRR. The UBC2-RAD18 complex is also involved in prevention of spontaneous mutations caused by 7,8-dihydro-8-oxoguanine. RAD18 is an E3 RING-finger protein belonging to the UBC2/RAD6 epistasis group. It contains a typical C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKRRKM 66
Cdd:cd23148    4 LRCHICKDLLKAPMRTPCNHTFCSFCIRTHLNNDARCPLCKAEVTESGL 52

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 157821155  19 LCSVCHGVLKRPMRLP-CSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16634    3 ICPICSGVLEEPLQAPhCEHAFCNACITEWLSRQQTCPVDR 43

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKE 60
Cdd:COG5432   23 DSMLRCRICDCRISIPCETTCGHTFCSLCIRRHLGTQPFCPVCRED 68

RING-finger-containing E3 ubiquitin ligase [Posttranslational modification, protein turnover, chaperones];

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 157821155   6 DLNLFASPPDCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNT--CPCCRKEVKRRKmvqVNKLRK 74
Cdd:COG5574  204 KKNGLPFIPLADYKCFLCLEEPEVPSCTPCGHLFCLSCLLISWTKKKYefCPLCRAKVYPKK---VIILRK 271

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 157821155  20 CSVCHGVLKRP---MRLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16454    2 CAICLEEFKEGekvRVLPCNHLFHKDCIDPWLEQHNTCPLCR 43

RING finger, HC subclass, found in Saccharomyces cerevisiae POB3/SPT16 histone-associated protein 1 (ScPSH1) and similar proteins; ScPSH1 is a Cse4-specific E3 ubiquitin ligase that interacts with the kinetochore protein Pat1 and targets the degradation of budding yeast centromeric histone H3 variant, CENP-ACse4, which is essential for faithful chromosome segregation. ScPSH1 contains a C3HC4-type RING-HC finger and a DNA directed RNA polymerase domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN--TCPCCRKEVKR 63
Cdd:cd16568    7 CIICHEYLYEPMVTTCGHTYCYTCLNTWFKSNRslSCPDCRTKITT 52

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 157821155   20 CSVCHGVLK---RPMRLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:pfam13639   3 CPICLEEFEegdKVVVLPCGHHFHRECLDKWLRSSNTCPLCR 44

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 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd23135    4 LSCSICFSEIRSGAILKCGHFFCLSCIASWLREKSTCPLCK 44

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

                         10        20        30
                 ....*....|....*....|....*....|....*..
gi 157821155  25 GVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEV 61
Cdd:COG5243  308 GLDMTPKRLPCGHILHLHCLKNWLERQQTCPICRRPV 344

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16514    2 LECSLCLRLLYEPVTTPCGHTFCRACLERCLDHSPKCPLCR 42

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCP 55
Cdd:cd16719    2 DPDLKCKLCGKVLEEPLSTPCGHVFCAGCLLPWAVQRRLCP 42

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIF-------QWLARQNTCPCCR 58
Cdd:cd16581    5 CSICYNIFDDPKILPCSHTFCKNCLEkllaasgYYLLASLKCPTCR 50

RING finger, H2 subclass, found in Tetratricopeptide repeat protein 3 (TTC3) and similar proteins; TTC3, also known as protein DCRR1, TPR repeat protein D, TPR repeat protein 3, or RING finger protein 105 (RNF105), is an E3 ubiquitin-protein ligase encoded by a gene within the Down syndrome (DS) critical region on chromosome 21. It affects differentiation and Golgi compactness in neurons through specific actin-regulating pathways. It inhibits the neuronal-like differentiation of pheocromocytoma cells by activating RhoA and by binding to Citron proteins. TTC3 is an Akt-specific E3 ligase that binds to phosphorylated Akt and facilitates its ubiquitination and degradation within the nucleus. It contains four N-terminal TPR motifs, a potential coiled-coil region and a Citron binding region in the central part, and a C-terminal C3H2C2-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 157821155  19 LCSVCHGVLKRPMR--LPCSHIFCKKCIFQWLARQNTCPCCRKEV 61
Cdd:cd16481    1 PCIICHDDLKPDQLakLECGHIFHKECIKQWLKEQSTCPTCRVHV 45

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEV 61
Cdd:cd16562    4 CHICLGKVRQPVICSNNHVFCSSCMDVWLKNNNQCPACRVPI 45

RING finger, HC subclass, found in RING finger protein 125 (RNF125); RNF125, also known as T-cell RING activation protein 1 (TRAC-1), is an E3 ubiquitin-protein ligase that is predominantly expressed in lymphoid cells, and functions as a positive regulator of T cell activation. It also down-modulates HIV replication and inhibits pathogen-induced cytokine production. It negatively regulates type I interferon signaling, which conjugates Lys(48)-linked ubiquitination to retinoic acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. Further, RNF125 conjugates ubiquitin to melanoma differentiation-associated gene 5 (MDA5), a family protein of RIG-I. It thus acts as a negative regulator of RIG-I signaling, and is a direct target of miR-15b in the context of Japanese encephalitis virus (JEV) infection. Moreover, RNF125 binds to and ubiquitinates JAK1, prompting its degradation and inhibition of receptor tyrosine kinase (RTK) expression. It also negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation. Mutations in RNF125 may lead to overgrowth syndromes (OGS). RNF125, together with three closely related proteins: RNF114, RNF138 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). The UIM of RNF125 binds K48-linked poly-ubiquitin chains and is, together with the RING domain, required for auto-ubiquitination.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 157821155  17 NFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN-TCPCCRKEVKR 63
Cdd:cd16542    1 NFDCAVCLEVLHQPVRTRCGHVFCRPCIATSLRNNTwTCPYCRAYLSS 48

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
                 ....*....|....*....|....*....|....*....|....*....
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQ----NTCPCCRKEVKRR 64
Cdd:cd16597    8 CSICLELFKDPVTLPCGHNFCGVCIEKTWDSQhgseYSCPQCRATFPRR 56

RING finger, H2 subclass, found in RING finger protein 126 (RNF126) and similar proteins; RNF126 is a Bag6-dependent E3 ubiquitin ligase that is involved in the mislocalized protein (MLP) pathway of quality control. It regulates the retrograde sorting of the cation-independent mannose 6-phosphate receptor (CI-MPR). Moreover, RNF126 promotes cancer cell proliferation by targeting the tumor suppressor p21 for ubiquitin-mediated degradation, and could be a novel therapeutic target in breast and prostate cancers. It is also able to ubiquitylate cytidine deaminase (AID), a poorly soluble protein that is essential for antibody diversification. In addition, RNF126 and the related protein, RNF115 associate with the epidermal growth factor receptor (EGFR) and promote ubiquitylation of EGFR, suggesting they play a role in the ubiquitin-dependent sorting and downregulation of membrane receptors. RNF126 contains an N-terminal BCA2 Zinc-finger domain (BZF), the AKT-phosphorylation sites, and the C-terminal C3H2C3-type RING-H2 finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 157821155  20 CSVC---HGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRK 59
Cdd:cd16801    2 CPVCkedYTVGENVRQLPCNHLFHNDCIVPWLEQHDTCPVCRK 44

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN----TCPCCRKEVKR 63
Cdd:cd16623   11 CPICLDFFSHPISLSCAHIFCFDCIQKWMTKREdsilTCPLCRKEQKK 58

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNT--CPCCRK 59
Cdd:cd16608    7 LLCSICLSIYQDPVSLGCEHYFCRQCITEHWSRSEHrdCPECRR 50

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

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 157821155    20 CSVCHGV-LKRPMRLPCSHIFCKKCIFQWL-ARQNTCPCC 57
Cdd:smart00184   1 CPICLEEyLKDPVILPCGHTFCRSCIRKWLeSGNNTCPIC 40

Zinc finger, C3HC4 type (RING finger);

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 157821155   20 CSVCHGVLKRPMRL-PCSHIFCKKCIFQWLARQNTCPCC 57
Cdd:pfam13923   2 CPICMDMLKDPSTTtPCGHVFCQDCILRALEASNECPLC 40

Modified RING finger domain; Modified RING finger domain, without the full complement of Zn2+-binding ligands. Probable involvement in E2-dependent ubiquitination.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*....
gi 157821155    18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKRRKMVQVNKLRKTI 76
Cdd:smart00504   2 FLCPISLEVMKDPVILPSGQTYERSAIEKWLLSHGTDPVTGQPLTHEDLIPNLALKSAI 60

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 157821155  15 DCNFLCSVCHGVLKRP---MRLPCSHIFCKKCIFQWLARQNTCPCCRKEVK 62
Cdd:cd16682    5 DTDEKCTICLSMLEDGedvRRLPCMHLFHQLCVDQWLAMSKKCPICRVDIE 55

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|..
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEV 61
Cdd:cd16546    3 CPICLQTCIHPVKLPCGHIFCYLCVKGVAWQSKRCALCRQEI 44

RING finger, HC subclass, found in tripartite motif-containing protein 69 (TRIM69) and similar proteins; TRIM69, also known as RFP-like domain-containing protein trimless or RING finger protein 36 (RNF36), is a testis E3 ubiquitin-protein ligase that plays a specific role in apoptosis and may also play an important role in germ cell homeostasis during spermatogenesis. TRIM69 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 157821155  20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN---TCPCCRKEVKRR 64
Cdd:cd16611    7 CPLCLDFFRDPVMLSCGHNFCQSCITGFWELQAedtTCPECRELCQYR 54

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRKEVKRRKMVQV 69
Cdd:cd16527    1 RKCSLCLEERRHPTATPCGHLFCWSCITEWCNEKPECPLCREPFQPQRLVPL 52

RING finger, HC subclass, found in constitutive photomorphogenesis protein 1 (COP1) and similar proteins; COP1, also known as RING finger and WD repeat domain protein 2 (RFWD2) or RING finger protein 200 (RNF200), is a central regulator of photomorphogenic development in plants, which targets key transcription factors for proteasome-dependent degradation. It is localized predominantly in the nucleus, but may also be present in the cytosol. Mammalian COP1 functions as an E3 ubiquitin-protein ligase that interacts with Jun transcription factors and modulates their transcriptional activity. It also interacts with and negatively regulates the tumor-suppressor protein p53. Moreover, COP1 associates with COP9 signalosome subunit 6 (CSN6), and is involved in 14-3-3sigma ubiquitin-mediated degradation. The CSN6-COP1 link enhances ubiquitin-mediated degradation of p27(Kip1), a critical CDK inhibitor involved in cell cycle regulation, to promote cancer cell growth. Furthermore, COP1 functions as the negative regulator of ETV1 and influences prognosis in triple-negative breast cancer. COP1 contains an N-terminal extension, a C3HC4-type RING-HC finger, a coiled coil domain, and seven WD40 repeats. In human COP1, a classic leucine-rich NES, and a novel bipartite NLS is bridged by the RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCC 57
Cdd:cd16504    3 FLCPICFDIIKEAFVTKCGHSFCYKCIVKHLEQKNRCPKC 42

RING finger, HC subclass, found in RING finger protein 168 (RNF168) and similar proteins; RNF168 is an E3 ubiquitin-protein ligase that promotes noncanonical K27 ubiquitination to signal DNA damage. It, together with RNF8, functions as a DNA damage response (DDR) factor that promotes a series of ubiquitylation events on substrates, such as H2A and H2AX with H2AK13/15 ubiquitylation, facilitates recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of double-strand breaks (DSBs), and inhibits homologous recombination (HR) in cells deficient in the tumor suppressor BRCA1. RNF168 also promotes H2A neddylation, which antagonizes ubiquitylation of H2A and regulates DNA damage repair. Moreover, RNF168 forms a functional complex with RAD6A or RAD6B during the DNA damage response. RNF168 contains an N-terminal C3HC4-type RING-HC finger that catalyzes H2A-K15ub and interacts with H2A, and two MIU (motif interacting with ubiquitin) domains responsible for the interaction with K63 linked poly-ubiquitin.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN-TCPCCRKEV 61
Cdd:cd16550    1 CLCPICLEILVEPVTLPCNHTLCMPCFQSTVEKASlCCPLCRLRI 45

RING finger, H2 subclass, found in RING finger protein 111 (RNF111) and similar proteins; RNF111, also known as Arkadia, is a nuclear E3 ubiquitin-protein ligase that targets intracellular effectors and modulators of transforming growth factor beta (TGF-beta)/Nodal-related signaling for polyubiquitination and proteasome-dependent degradation. It acts as an amplifier of Nodal signals, and enhances the dorsalizing activity of limiting amounts of Xnr1, a Nodal homolog, and requires Nodal signaling for its function. The loss of RNF111 results in early embryonic lethality, with defects attributed to compromised Nodal signaling. RNF111 also regulates tumor metastasis by modulation of the TGF-beta pathway. Its ubiquitination can be modulated by the four and a half LIM-only protein 2 (FHL2) that activates TGF-beta signal transduction. Furthermore, RNF111 interacts with the clathrin-adaptor 2 (AP2) complex and regulates endocytosis of certain cell surface receptors, leading to modulation of epidermal growth factor (EGF) and possibly other signaling pathways. In addition, RNF111 has been identified as a small ubiquitin-like modifier (SUMO)-binding protein with clustered SUMO-interacting motifs (SIMs) that together form a SUMO-binding domain (SBD). It thus functions as a SUMO-targeted ubiquitin ligase (STUbL) that directly links nonproteolytic ubiquitylation and SUMOylation in the DNA damage response, as well as triggers degradation of signal-induced polysumoylated proteins, such as the promyelocytic leukemia protein (PML). The N-terminal half of RNF111 harbors three SIMs. Its C-terminal half show high sequence similarity with RING finger protein 165 (RNF165), where it contains two serine rich domains, two nuclear localization signals, an NRG-TIER domain, and a C-terminal C3H2C3-type RING-H2 finger that is required for polyubiqutination and proteasome-dependent degradation of phosphorylated forms of Smad2/3 and three major negative regulators of TGF-beta signaling, Smad7, SnoN and c-Ski.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 157821155  20 CSVCHGVLKRP---MRLPCSHIFCKKCIFQWLARQNTCPCCRKEVK 62
Cdd:cd16681   13 CTICLSILEEGedvRRLPCMHLFHQVCVDQWLITNKKCPICRVDIE 58

RING finger, H2 subclass, found in RING finger proteins RNF111, RNF165, and similar proteins; The family includes RING finger proteins RNF111, RNF165, and similar proteins. RNF111, also known as Arkadia, is a nuclear E3 ubiquitin-protein ligase that targets intracellular effectors and modulators of transforming growth factor beta (TGF-beta)/Nodal-related signaling for polyubiquitination and proteasome-dependent degradation. It also interacts with the clathrin-adaptor 2 (AP2) complex and regulates endocytosis of certain cell surface receptors, leading to modulation of epidermal growth factor (EGF) and possibly other signaling pathways. The N-terminal half of RNF111 harbors three SUMO-interacting motifs (SIMs). It thus functions as a SUMO-targeted ubiquitin ligase (STUbL) that directly links nonproteolytic ubiquitylation and SUMOylation in the DNA damage response, as well as triggers degradation of signal-induced polysumoylated proteins, such as the promyelocytic leukemia protein (PML). RNF165, also known as Arkadia-like 2, Arkadia2, or Ark2C, is an E3 ubiquitin ligase with homology to the C-terminal half of RNF111. It is expressed specifically in the nervous system, and can serve to amplify neuronal responses to specific signals. It acts as a positive regulator of bone morphogenetic protein (BMP)-Smad signaling that is involved in motor neuron (MN) axon elongation. Both RNF165 and RNF111 contain a C-terminal C3H2C3-type RING-H2 finger.

                         10        20
                 ....*....|....*....|....*..
gi 157821155  32 RLPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16474   18 RLPCMHLFHQECVDQWLSTNKRCPICR 44

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

                         10        20        30
                 ....*....|....*....|....*....|....*...
gi 157821155  33 LPCSHIFCKKCIFQWLARQN-TCPCCRKEVKRRKMVQV 69
Cdd:cd16450   23 LKCGHLFGYSCIEKWLKGKGkKCPQCNKKAKRSDIRPL 60

RING finger, HC subclass, found in Candida albicans transcriptional regulator of yeast form adherence 3 (TRY3) and similar proteins; TRY3 acts as a transcription factor required for yeast cell adherence to silicone substrate. It contains a typical C3HC4-type RING-HC finger.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 157821155  17 NFLCSVCHGVLKRPMRLPCSHIFCKKCIFQwLARQN--TCPCCRKEV 61
Cdd:cd23137    2 DYACPICMNVAWKPVRLECSHVFCLRCLVK-AQKQKkdNCPLCRAKG 47

RING finger, HC subclass, found in tripartite motif-containing protein 39 (TRIM39) and similar proteins; TRIM39, also known as RING finger protein 23 (RNF23) or testis-abundant finger protein, is an E3 ubiquitin-protein ligase that plays a role in controlling DNA damage-induced apoptosis through inhibition of the anaphase promoting complex (APC/C), a multiprotein ubiquitin ligase that controls multiple cell cycle regulators, including cyclins, geminin, and others. TRIM39 also functions as a regulator of several key processes in the proliferative cycle. It directly regulates p53 stability. It modulates cell cycle progression and DNA damage responses via stabilizing p21. Moreover, TRIM39 negatively regulates the nuclear factor kappaB (NFkappaB)-mediated signaling pathway through stabilization of Cactin, an inhibitor of NFkappaB- and Toll-like receptor (TLR)-mediated transcription, which is induced by inflammatory stimulants such as tumor necrosis factor alpha. Furthermore, TRIM39 is a MOAP-1-binding protein that can promote apoptosis signaling through stabilization of MOAP-1 via the inhibition of its poly-ubiquitination process. TRIM39 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 157821155  18 FLCSVCHGVLKRPMRLPCSHIFCKKCIFQW---LARQNTCPCC 57
Cdd:cd16601    2 ASCSLCKEYLKDPVIIECGHNFCRACITRFweeLDGDFPCPQC 44

Modified RING finger, HC subclass (C3HC3D-type), found in ligand of numb protein X 2 (LNX2); LNX2, also known as numb-binding protein 2, or PDZ domain-containing RING finger protein 1 (PDZRN1), is a PDZ domain-containing RING-type E3 ubiquitin ligase responsible for the ubiquitination and degradation of Numb, a component of the Notch signaling pathway that functions in the specification of cell fates during development and is known to control cell numbers during neurogenesis in vertebrates. It interacts with contactin-associated protein 4 (Caspr4, also known as CNTNAP4) in a PDZ domain-dependent manner, which modulates the proliferation and neuronal differentiation of neural progenitor cells (NPCs). LNX2 contains an N-terminal modified C3HC3D-type RING-HC finger, a NPAF motif for Numb/ Numblike-LNX interaction, and four PDZ domains necessary for the binding of substrates, including ErbB2, RhoC, the presynaptic protein CAST, the melanoma/cancer-testis antigen MAGEB18 and several proteins associated with cell junctions, such as JAM4 and the Coxsackievirus and adenovirus receptor (CAR).

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 157821155  15 DCNFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQNTCPCCRK 59
Cdd:cd16780    1 DDDLVCHICLQPLLQPLDTPCGHTFCFKCLRNFLQEKDFCPLDRK 45

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
                 ....*....|....*....|....*...
gi 157821155  32 RLP-CSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16461   17 RLPeCKHAFHKECIDEWLKSNSTCPLCR 44

Modified RING finger, HC subclass (C4C4-type), found in tripartite motif-containing protein 37 (TRIM37) and similar proteins; TRIM37, also known as mulibrey nanism protein, or MUL, is a peroxisomal E3 ubiquitin-protein ligase that is involved in the tumorigenesis of several cancer types, including pancreatic ductal adenocarcinoma (PDAC), hepatocellular carcinoma (HCC), breast cancer, and sporadic fibrothecoma. It mono-ubiquitinates histone H2A, a chromatin modification associated with transcriptional repression. Moreover, TRIM37 possesses anti-HIV-1 activity, and interferes with viral DNA synthesis. Mutations in the human TRIM37 gene (also known as MUL) cause Mulibrey (muscle-liver-brain-eye) nanism, a rare growth disorder of prenatal onset characterized by dysmorphic features, pericardial constriction, and hepatomegaly. TRIM37 belongs to the C-VIII 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 C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a MATH (meprin and TRAF-C homology) domain positioned C-terminal to the RBCC domain. Its MATH domain has been shown to interact with the TRAF (TNF-Receptor-Associated Factor) domain of six known TRAFs in vitro.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 157821155  18 FLCSVCHGVLKRPMRLP-CSHIFCKKCIFQWLARQ-NTCPCCR 58
Cdd:cd16619    1 FRCFICMEKLRDPRLCPhCSKLFCKGCIRRWLSEQrSSCPHCR 43

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 157821155   20 CSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQN----TCPCC 57
Cdd:pfam15227   1 CPICLDYLEKPVSIECGHSFCLSCINSLQKEPDgeslLCPQC 42

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 157821155  20 CSVCHGVLKRPMRLP-CSHIFCKKCIFQWLARQNTCPCCRKEVK 62
Cdd:cd16529    7 CPICFEYFNTAMMITqCSHNYCSLCIRRFLSYKTQCPTCRAAVT 50

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
                 ....*....|....*....|....*....|....*....|....*...
gi 157821155  15 DCNFLCSVCHGVLKRPMRL-PCSHIFCKKCIFQWLARQNTCPCCRKEV 61
Cdd:cd16683    2 EIDDVCAICYQEFTTSARItPCNHYFHALCLRKWLYIQDTCPMCHQKV 49

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
                 ....*....|....*....|....*.
gi 157821155  33 LPCSHIFCKKCIFQWLARQNTCPCCR 58
Cdd:cd16465   18 LPCHHLFHKPCITAWLQKSGTCPVCR 43

Seven in absentia protein family; The seven in absentia (sina) gene was first identified in Drosophila. The Drosophila Sina protein is essential for the determination of the R7 pathway in photoreceptor cell development: the loss of functional Sina results in the transformation of the R7 precursor cell to a non- neuronal cell type. The Sina protein contains an N-terminal RING finger domain pfam00097. Through this domain, Sina binds E2 ubiquitin-conjugating enzymes (UbcD1) Sina also interacts with Tramtrack (TTK88) via PHYL. Tramtrack is a transcriptional repressor that blocks photoreceptor determination, while PHYL down-regulates the activity of TTK88. In turn, the activity of PHYL requires the activation of the Sevenless receptor tyrosine kinase, a process essential for R7 determination. It is thought that thus Sina targets TTK88 for degradation, therefore promoting the R7 pathway. Murine and human homologs of Sina have also been identified. The human homolog Siah-1 also binds E2 enzymes (UbcH5) and through a series of physical interactions, targets beta-catenin for ubiquitin degradation. Siah-1 expression is enhanced by p53, itself promoted by DNA damage. Thus this pathway links DNA damage to beta-catenin degradation. Sina proteins, therefore, physically interact with a variety of proteins. The N-terminal RING finger domain that binds ubiquitin conjugating enzymes is described in pfam00097, and does not form part of the alignment for this family. The remainder C-terminal part is involved in interactions with other proteins, and is included in this alignment. In addition to the Drosophila protein and mammalian homologs, whose similarity was noted previously, this family also includes putative homologs from Caenorhabditis elegans, Arabidopsis thaliana.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 157821155   79 LQVKCKNAAAGCLVTCPLAHRKGHQDSCPFELMACPNEG--CTAQvlrGVLDEHRQHCQQ 136
Cdd:pfam03145  13 LLFPCKYASSGCSETLPYTEKADHEERCEFRPYSCPCPGssCTWQ---GSLDAVMPHLMD 69

RING finger, HC subclass, found in tripartite motif-containing protein 77 (TRIM77) and similar proteins; TRIM77 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including two consecutive zinc-binding domains, a C3HC4-type RING-HC finger and Bbox2, as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 157821155  17 NFLCSVCHGVLKRPMRLPCSHIFCKKCIFQWLARQ---NTCPCCRKEVKRR 64
Cdd:cd16543    3 QLTCSICLDLLKDPVTIPCGHSFCMNCITLLWDRKqgvPSCPQCRESFPPR 53

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 157821155   20 CSVCHGVLKRPMR-LPCSHIFCKKCIFQWL-ARQNTCPCC 57
Cdd:pfam00097   1 CPICLEEPKDPVTlLPCGHLFCSKCIRSWLeSGNVTCPLC 40