Modified RING finger, HC subclass (C3HC5-type), found in RING finger protein 26 (RNF26) and similar proteins; RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination of MITA after viral infection, and promoting the degradation of IRF3, another important component required for virus-triggered interferon induction. Although RNF26 substrates of ubiquitination remain unclear at present, RNF26 upregulation in gastric cancer might be implicated in carcinogenesis through dysregulation of growth regulators. RNF26 contains an N-terminal leucine zipper domain and a C-terminal modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 14042925 373 EQEERKKCVICQDQSKTVLLLPCRHLCLCQACTEILMRHPVYHRNCPLCRRGILQTLNVY 432
Cdd:cd16788   1 EERDKKKCVICQDQSKTVLILPCRHMCLCRQCANILLQQPVYRRNCPLCRTMILQTLDVY 60

Modified RING finger, HC subclass (C3HC5-type), found in RING finger protein 26 (RNF26) and similar proteins; RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination of MITA after viral infection, and promoting the degradation of IRF3, another important component required for virus-triggered interferon induction. Although RNF26 substrates of ubiquitination remain unclear at present, RNF26 upregulation in gastric cancer might be implicated in carcinogenesis through dysregulation of growth regulators. RNF26 contains an N-terminal leucine zipper domain and a C-terminal modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 14042925 373 EQEERKKCVICQDQSKTVLLLPCRHLCLCQACTEILMRHPVYHRNCPLCRRGILQTLNVY 432
Cdd:cd16788   1 EERDKKKCVICQDQSKTVLILPCRHMCLCRQCANILLQQPVYRRNCPLCRTMILQTLDVY 60

DNA repair protein rad18; All proteins in this family for which functions are known are involved in nucleotide excision repair.This family is based on the phylogenomic analysis of JA Eisen (1999, Ph.D. Thesis, Stanford University). [DNA metabolism, DNA replication, recombination, and repair]

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 14042925   365 QDPWKLLKEQEERKKCVICQDQSKTVLLLPCRHlCLCQACteiLMRHPVYHRNCPLCR 422
Cdd:TIGR00599  14 TTPIPSLYPLDTSLRCHICKDFFDVPVLTSCSH-TFCSLC---IRRCLSNQPKCPLCR 67

Modified RING finger, HC subclass (C3HC5-type), found in RING finger protein 26 (RNF26) and similar proteins; RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination of MITA after viral infection, and promoting the degradation of IRF3, another important component required for virus-triggered interferon induction. Although RNF26 substrates of ubiquitination remain unclear at present, RNF26 upregulation in gastric cancer might be implicated in carcinogenesis through dysregulation of growth regulators. RNF26 contains an N-terminal leucine zipper domain and a C-terminal modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 14042925 373 EQEERKKCVICQDQSKTVLLLPCRHLCLCQACTEILMRHPVYHRNCPLCRRGILQTLNVY 432
Cdd:cd16788   1 EERDKKKCVICQDQSKTVLILPCRHMCLCRQCANILLQQPVYRRNCPLCRTMILQTLDVY 60

Modified RING finger, HC subclass (C3HC5-type), found in RING finger proteins, RNF26, RNF197 (CGRRF1), RNF156 (MGRN1), RNF157 and similar proteins; This subfamily corresponds to a group of RING finger proteins containing a modified C3HC5-type RING-HC finger, which is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain. Cell growth regulator with RING finger domain protein 1 (CGRRF1), also known as cell growth regulatory gene 19 protein (CGR19) or RING finger protein 197 (RNF197), functions as a novel biomarker to monitor endometrial sensitivity and response to insulin-sensitizing drugs, such as metformin, in the context of obesity. RNF26 is an E3 ubiquitin ligase that temporally regulates virus-triggered type I interferon induction by increasing the stability of Mediator of IRF3 activation, MITA, also known as STING, through K11-linked polyubiquitination after viral infection and promoting degradation of IRF3, another important component required for virus-triggered interferon induction. Mahogunin ring finger-1 (MGRN1), also known as RING finger protein 156 (RNF156), is a cytosolic E3 ubiquitin-protein ligase that inhibits signaling through the G protein-coupled melanocortin receptors-1 (MC1R), -2 (MC2R) and -4 (MC4R) via ubiquitylation-dependent and -independent processes. It suppresses chaperone-associated misfolded protein aggregation and toxicity. RNF157 is a cytoplasmic E3 ubiquitin ligase predominantly expressed in the brain. It is a homolog of the E3 ligase MGRN1. In cultured neurons, it promotes neuronal survival in an E3 ligase-dependent manner. In contrast, it supports growth and maintenance of dendrites independent of its E3 ligase activity. RNF157 interacts with and ubiquitinates the adaptor protein APBB1 (amyloid beta precursor protein-binding, family B, member 1 or Fe65), which regulates neuronal survival, but not dendritic growth downstream of RNF157. The nuclear localization of APBB1 together with its interaction partner RNA-binding protein SART3 (squamous cell carcinoma antigen recognized by T cells 3 or Tip110) is crucial to trigger apoptosis.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 14042925 378 KKCVICQDQSKTVLLLPCRHLCLCQACTEILMRhpvyhRNCPLCR 422
Cdd:cd16649   1 GLCVVCLENPASVLLLPCRHLCLCEVCAKGLRG-----KTCPICR 40

RING finger, HC subclass, found in leucine-rich repeat and sterile alpha motif-containing protein 1 (LRSAM1) and similar proteins; LRSAM1, also known as Tsg101-associated ligase (TAL), or RIFLE, is an E3 ubiquitin-protein ligase that physically associates with, and selectively ubiquitylates, Tsg101, an E2-like molecule that regulates vesicular trafficking processes in yeast and mammals. It regulates a Tsg101-associated complex responsible for the sorting of cargo into cytoplasm-containing vesicles that bud at the multivesicular body and at the plasma membrane. LRSAM1 is a multidomain protein containing an N-terminal leucine-rich repeat (LRR), followed by several recognizable motifs, including an ezrin-radixin-moezin (ERM) domain, a coiled-coil (CC) region, a SAM domain, and a C-terminal C3HC4-type RING-HC finger domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 14042925 380 CVICQDQSKTVLLLPCRHLCLCQACTEILmrhpvyhRNCPLCRRGILQTL 429
Cdd:cd16515   4 CVVCMDAESQVIFLPCGHVCCCQTCSSSL-------STCPLCRADITQRV 46

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 14042925 380 CVICQDQSKTVLLLPCRHLCLCQACTEILMRhpvYHRNCPLCRRGILQTLNVY 432
Cdd:cd16647   4 CVICYERPVDTVLYRCGHMCMCYDCALQLKR---RGGSCPICRAPIKDVIKIY 53

RING finger, HC subclass, found in E3 ubiquitin-protein ligase XIAP, baculoviral IAP repeat-containing protein 8 (BIRC8) and similar proteins; XIAP, also known as baculoviral IAP repeat-containing protein 4 (BIRC4), IAP-like protein (ILP), inhibitor of apoptosis protein 3 (IAP-3), or X-linked inhibitor of apoptosis protein (X-linked IAP), is a potent suppressor of apoptosis that directly inhibits specific members of the caspase family of cysteine proteases, including caspase-3, -7, and -9. It promotes proteasomal degradation of caspase-3 and enhances its anti-apoptotic effect in Fas-induced cell death. The ubiquitin-protein ligase (E3) activity of XIAP also exhibits in the ubiquitination of second mitochondria-derived activator of caspases (Smac). The mitochondrial proteins, Smac/DIABLO and Omi/HtrA2, can inhibit the antiapoptotic activity of XIAP. XIAP has also been implicated in several intracellular signaling cascades involved in the cellular response to stress, such as the c-Jun N-terminal kinase (JNK), the nuclear factor-kappaB (NF-kappaB), and the transforming growth factor-beta (TGF-beta) pathways. Moreover, XIAP can regulate copper homeostasis by interacting with MURR1. BIRC8, also known as inhibitor of apoptosis-like protein 2, IAP-like protein 2, ILP-2, or testis-specific inhibitor of apoptosis, is a tissue-specific homolog of E3 ubiquitin-protein ligase XIAP. It has been implicated in the control of apoptosis in the testis by direct inhibition of caspase 9. Both XIAP and BIRC8 contain three N-terminal baculoviral IAP repeat (BIR) domains, a ubiquitin-association (UBA) domain and a C3HC4-type RING-HC finger at the carboxyl terminus.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 14042925 366 DPWKLLKEQEERKKCVICQDQSKTVLLLPCRHLCLCQACTEILMRhpvyhrnCPLCRRGILQTLNVYL 433
Cdd:cd16714   3 STEEKLRRLQEEKLCKICMDRNISIVFIPCGHLVTCKQCAEALDK-------CPICCTVITFKQKIFM 63

RING finger, HC subclass, found in inhibitor of apoptosis proteins (IAPs); IAPs are frequently overexpressed in cancer and associated with tumor cell survival, chemoresistance, disease progression, and poor prognosis. They function primarily as negative regulators of cell death. They regulate caspases and apoptosis through the inhibition of specific members of the caspase family of cysteine proteases. In addition, IAPs has been implicated in a multitude of other cellular processes, including inflammatory signalling and immunity, mitogenic kinase signalling, proliferation and mitosis, as well as cell invasion and metastasis. IAPs in this family includes cellular inhibitor of apoptosis protein c-IAP1 (BIRC2) and c-IAP2 (BIRC3), XIAP (BIRC4), BIRC7, and BIRC8, all of which contain three N-terminal baculoviral IAP repeat (BIR) domains that enable interactions with proteins, a ubiquitin-association (UBA) domain that is responsible for the binding of polyubiquitin (polyUb), and a C3HC4-type RING-HC finger at the carboxyl terminus that is required for ubiquitin ligase activity. The UBA domain is only absent in mammalian homologs of BIRC7. Moreover, c-IAPs contains an additional caspase activation and recruitment domain (CARD) between the UBA and C3HC4-type RING-HC domains. The CARD domain may serve as a protein interaction surface.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 14042925 378 KKCVICQDQSKTVLLLPCRHLCLCQACTEILmrhpvyhRNCPLCR 422
Cdd:cd16510   2 KLCKICMDREVNIVFLPCGHLVTCAQCAASL-------RKCPICR 39

Modified RING finger, HC subclass (C3HC5-type), found in RING finger protein 157 (RNF157) and similar proteins; RNF157 is a cytoplasmic E3 ubiquitin ligase predominantly expressed in brain. It is a homolog of the E3 ligase mahogunin ring finger-1 (MGRN1). In cultured neurons, it promotes neuronal survival in an E3 ligase-dependent manner. In contrast, it supports growth and maintenance of dendrites independent of its E3 ligase activity. RNF157 interacts with and ubiquitinates the adaptor protein APBB1 (amyloid beta precursor protein-binding, family B, member 1 or Fe65), which regulates neuronal survival, but not dendritic growth downstream of RNF157. The nuclear localization of APBB1 together with its interaction partner RNA-binding protein SART3 (squamous cell carcinoma antigen recognized by T cells 3 or Tip110) is crucial to trigger apoptosis. RNF157 contains a modified C3HC5-type RING-HC finger, and a functionally uncharacterized region, known as domain associated with RING2 (DAR2), N-terminal to the RING finger. The C3HC5-type RING-HC finger is distinguished from typical C3HC4 RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|..
gi 14042925 379 KCVICQDQSKTVLLLPCRHLCLCQACTEILMRHPvyhRNCPLCR---RGILQ 427
Cdd:cd16817   6 ECVVCLSDVRDTLILPCRHLCLCNACADTLRYQA---NNCPICRlpfRALLQ 54

RING finger, HC subclass, found in apoptosis protein c-IAP1, c-IAP2, livin, and similar proteins; The cellular inhibitor of apoptosis protein c-IAPs function as ubiquitin E3 ligases that mediate the ubiquitination of substrates involved in apoptosis, nuclear factor-kappaB (NF-kappaB) signaling, and oncogenesis. Unlike other IAPs, such as XIAP, c-IAPs exhibit minimal binding to caspases and may not play an important role in the inhibition of these proteases. c-IAP1, also known as baculoviral IAP repeat-containing protein BIRC2, IAP-2, RING finger protein 48, or TNFR2-TRAF-signaling complex protein 2, is a potent regulator of the tumor necrosis factor (TNF) receptor family and NF-kappaB signaling pathways in the cytoplasm. It can also regulate E2F1 transcription factor-mediated control of cyclin transcription in the nucleus. c-IAP2, also known as BIRC3, IAP-1, apoptosis inhibitor 2 (API2), or IAP homolog C, also influences ubiquitin-dependent pathways that modulate innate immune signalling by activation of NF-kappaB. c-IAPs contain three N-terminal baculoviral IAP repeat (BIR) domains that enable interactions with proteins, a ubiquitin-association (UBA) domain that is responsible for the binding of polyubiquitin (polyUb), a caspase activation and recruitment domain (CARD) that serves as a protein interaction surface, and a C3HC4-type RING-HC finger at the carboxyl terminus that is required for ubiquitin ligase activity. Livin, also known as baculoviral IAP repeat-containing protein 7 (BIRC7), kidney inhibitor of apoptosis protein (KIAP), melanoma inhibitor of apoptosis protein (ML-IAP), or RING finger protein 50, was identified as the melanoma IAP. It plays crucial roles in apoptosis, cell proliferation, and cell cycle control. Its anti-apoptotic activity is regulated by the inhibition of caspase-3, -7, and -9. Its E3 ubiquitin-ligase-like activity promotes degradation of Smac/DIABLO, a critical endogenous regulator of all IAPs. Unlike other family members, mammalian livin contains a single BIR domain and a C3HC4-type RING-HC finger. The UBA domain can be detected in non-mammalian homologs of livin.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 14042925 370 LLKEQEERKkCVICQDQSKTVLLLPCRHLCLCQACTEILmrhpvyhRNCPLCRRGILQTLNVYL 433
Cdd:cd16713   1 LRRLQEERT-CKVCMDKEVSIVFIPCGHLVVCTECAPSL-------RKCPICRATIKGTVRTFL 56

Modified RING finger, HC subclass (C3HC5-type), found in neuralized-like protein 1B (NEURL1B); NEURL1B, also known as neuralized-2 (NEUR2) or neuralized-like protein 3, is a mammalian homolog of the Drosophila neuralized (D-neu) protein. It functions as an E3 ubiquitin-protein ligase that interacts with and ubiquitinates Delta. Thus, it plays a role in the endocytic pathways for Notch signaling through working cooperatively with another E3 ligase, Mind bomb-1 (Mib1), in Delta endocytosis to hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs)-positive vesicles. NEURL1B contains two neuralized homology regions (NHRs) responsible for Neural-ligand interactions and a modified C3HC5-type RING-HC finger required for ubiquitin ligase activity. The C3HC5-type RING-HC finger is distinguished from typical C3HC4-type RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 14042925 379 KCVICQDQSKTVLLLPCRHLCLCQACTEILMRHpvYHRNCPLCRRGILQTLNVY 432
Cdd:cd16786   4 ECTVCFDSEVDTVIYTCGHMCLCNSCGLKLKRQ--INACCPICRRVIKDVIKIY 55

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 14042925 380 CVICQDQsKTVLLLPCRHLcLCQACTEilmRHPVYHRNCPLCR 422
Cdd:cd16545   3 CCICMDR-KADLILPCAHS-YCQKCID---KWSDRHRTCPICR 40

RING finger, HC subclass, found in RING finger protein unkempt-like (UNKL) and similar proteins; UNKL, also known as zinc finger CCCH domain-containing protein 5-like, is a putative E3 ubiquitin-protein ligase that may participate in a protein complex showing an E3 ligase activity regulated by RAC1. It shows high sequence similarity with RING finger protein unkempt (UNK), which is a metazoan-specific zinc finger protein enriched in embryonic brains, and may play a broad regulatory role during the formation of the central nervous system (CNS). UNKL contains several CCCH-type zinc fingers at the N-terminus, and a C3HC4-type RING-HC finger at its C-terminus.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 14042925 378 KKCVICQDQSKTVLLLPCRHLCLCQACTEilmrhpvYHRNCPLCRRGILQ 427
Cdd:cd16772   1 KKCIVCQERDRSIVLQPCQHYVLCEHCAA-------SKPECPYCKTKILK 43

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

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 14042925 380 CVICQDQSKTVLLLPCR--HLCLCQACTEILMRHPvyhRNCPLCRRGI 425
Cdd:cd16646   3 CVICLSRPRTAAIVHGKtgHQVACYTCAKKLKRRG---KPCPVCRRPI 47

Modified RING finger, HC subclass (C4C4-type), found in Saccharomyces cerevisiae amino acid sensor-independent protein Asi1p, Asi3p and similar proteins; Asi1p and Asi3p are inner nuclear membrane proteins that act as negative regulators of SPS (Ssy1-Ptr3-Ssy5)-sensor signaling in yeast. Together with Asi2p, they assemble into an Asi complex that functions in the SPS amino acid sensing pathway involved in degradation of Stp1 and Stp2 transcription factors. Both Asi1p and Asi3p contain five membrane-spanning domains, as well as highly conserved RING fingers at their extreme C termini, which are C4C4-type RING finger motifs whose overall folding is similar to that of the C3HC4-type RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 14042925 377 RKKCVICQDQSKTVLLLPCRHLCLCQACTEIL-MRHpvYHRnCPLCRR 423
Cdd:cd16616   1 DLSCVICKSNPRNIVLWPCRCLALCDDCRLSLaMRG--FHT-CVCCRR 45

DNA repair protein rad18; All proteins in this family for which functions are known are involved in nucleotide excision repair.This family is based on the phylogenomic analysis of JA Eisen (1999, Ph.D. Thesis, Stanford University). [DNA metabolism, DNA replication, recombination, and repair]

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 14042925   365 QDPWKLLKEQEERKKCVICQDQSKTVLLLPCRHlCLCQACteiLMRHPVYHRNCPLCR 422
Cdd:TIGR00599  14 TTPIPSLYPLDTSLRCHICKDFFDVPVLTSCSH-TFCSLC---IRRCLSNQPKCPLCR 67

second RING finger, HC subclass, found in mind bomb 1 (MIB1) and similar proteins; MIB1, also known as DAPK-interacting protein 1 (DIP-1) or zinc finger ZZ type with ankyrin repeat domain protein 2, is a large, multi-domain E3 ubiquitin-protein ligase that promotes ubiquitination of the cytoplasmic tails of Notch ligands, and thus plays an essential role in controlling metazoan development by Notch signaling. It is also involved in Wnt/beta-catenin signaling and nuclear factor (NF)-kappaB signaling, and has been implicated in innate immunity, neuronal function, genomic stability, and cell death. MIB1 contains an MZM region with two Mib-Herc2 domains flanking a ZZ zinc finger, a REP region including two tandem Mib repeats, an ANK region that spans ankyrin repeats, and a RNG region consisting of three C3HC4-type RING-HC fingers. This model corresponds to the second RING-HC finger.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*
gi 14042925 378 KKCVICQDQSKTVLLLPCRHLCLCQACTEILmrhpvyhRNCPLCR 422
Cdd:cd16725   1 EECVVCSDKKASVLFKPCGHMCACEGCAALM-------KKCVQCR 38

RING finger, HC subclass, found in Dictyostelium discoideum Cbl-like protein A (CblA) and similar proteins; CblA is a Dictyostelium homolog of the Cbl proteins which are multi-domain proteins acting as key negative regulators of various receptor and non-receptor tyrosine kinase signaling. CblA upregulates STATc tyrosine phosphorylation by downregulating PTP3, the protein tyrosine phosphatase responsible for dephosphorylating STATc. STATc is a signal transducer and activator of transcription protein. Like other Cbl proteins, CblA contains a tyrosine-kinase-binding domain (TKB), a proline-rich domain, a C3HC4-type RING-HC finger, and an ubiquitin-associated (UBA) domain. TKB, also known as a phosphotyrosine binding PTB domain, is composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain. This family also includes Drosophila melanogaster defense repressor 1 (Dnr1) that was identified as an inhibitor of Dredd activity in the absence of a microbial insult in Drosophila S2 cells. It inhibits the Drosophila initiator caspases Dredd and Dronc. Moreover, Dnr1 acts as a negative regulator of the Imd (immune deficiency) innate immune-response pathway. Its mutations cause neurodegeneration in Drosophila by activating the innate immune response in the brain. Dnr1 contains a FERM N-terminal domain followed by a region rich in glutamine and serine residues, a central FERM domain, and a C-terminal C3HC4-type RING-HC finger.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 14042925 375 EERKKCVICQDQSKTVLLLPCRHLCLCQACTEILmrhpvyhRNCPLCRRGILQTLNVY 432
Cdd:cd16501   3 ADADLCVVCMDAPIDTVFLECGHLACCRLCSKRL-------RVCPICRQPISRVVRIF 53

RING finger, HC subclass, found in RNA-binding protein MEX3C; MEX3C, also known as RING finger and KH domain-containing protein 2 (RKHD2), or RING finger protein 194 (RNF194), is an RNA-binding phosphoprotein that acts as a suppressor of chromosomal instability. It functions as an ubiquitin E3 ligase responsible for the post-transcriptional, HLA-A allotype-specific regulation of MHC class I molecules (MHC-I). It also modifies retinoic acid inducible gene-1 (RIG-I) in stress granules and plays a critical role in eliciting antiviral immune responses. Moreover, MEX3C plays an essential role in normal postnatal growth via enhancing the local expression of insulin-like growth factor 1 (IGF1) in bone. It may also be involved in metabolic regulation of energy balance. MEX3C contains two K homology (KH) domains that provide RNA-binding capacity, and a C-terminal C3HC4-type RING-HC finger. Like other MEX-3 family proteins, MEX3C shuttles between the nucleus and the cytoplasm via the CRM1-dependent export pathway.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*.
gi 14042925 377 RKKCVICQDQSKTVLLLPCRHLCLCQACTEILMRHPVyhRNCPLCRRGILQTLNVY 432
Cdd:cd16722   1 KHDCVICFENEVIAALVPCGHNLFCMECANKICEKET--PSCPVCQTAVTQAIQIH 54

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 14042925 380 CVICQDQSK---TVLLLPCRHLCLCQACTEILMRHpvyhRNCPLCR 422
Cdd:cd16454   2 CAICLEEFKegeKVRVLPCNHLFHKDCIDPWLEQH----NTCPLCR 43