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
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1720430095 471 LRRLQEERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTFLS 527
Cdd:cd16713     1 LRRLQEERTCKVCMDKEVSIVFIPCGHLVVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1720430095  176 TEEARFLTYSMWP-LSFLSPAELARAGFYYIGPGDRVACFACGGKLSNWEPKDDAMSEHRRHFPHCPFLEN 245
Cdd:smart00238   1 SEEARLKTFQNWPyNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

UBA domain found in baculoviral IAP repeat-containing protein BIRC2, BIRC3 and similar proteins; The subfamily includes cellular inhibitor of apoptosis protein 1 (c-IAP1) and c-IAP2. c-IAPs function as ubiquitin E3 ligases that mediate the ubiquitination of the substrates involved in apoptosis, nuclear factor-kappaB (NF-kappaB)signaling, and oncogenesis. Unlike other apoptosis proteins (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 called 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 called 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 binds polyubiquitin (polyUb), a caspase activation and recruitment domain (CARD) that serves as a protein interaction surface, and a RING domain at the carboxyl terminus that is required for ubiquitin ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1720430095 385 MSTPVVKAALEMGFSRSLVRQTVQRQILATGENYRTVNDIVSVLLNA 431
Cdd:cd14394     1 MNTPVVKSALEMGFNRRLVKQTVQSKILTSGENYKTVNDLVSDLLSA 47

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
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1720430095 471 LRRLQEERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTFLS 527
Cdd:cd16713     1 LRRLQEERTCKVCMDKEVSIVFIPCGHLVVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1720430095  261 THSARLRTFLYWPPSVPVQPEQLASAGFYYVDRNDDVKCFCCDGGLRCWEPGDDPWIEHAKWFPRCEFL 329
Cdd:smart00238   1 SEEARLKTFQNWPYNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFV 69

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1720430095  176 TEEARFLTYSMWP-LSFLSPAELARAGFYYIGPGDRVACFACGGKLSNWEPKDDAMSEHRRHFPHCPFLEN 245
Cdd:smart00238   1 SEEARLKTFQNWPyNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

Inhibitor of Apoptosis domain; BIR stands for 'Baculovirus Inhibitor of apoptosis protein Repeat'. It is found repeated in inhibitor of apoptosis proteins (IAPs), and in fact it is also known as IAP repeat. These domains characteriztically have a number of invariant residues, including 3 conserved cysteines and one conserved histidine that coordinate a zinc ion. They are usually made up of 4-5 alpha helices and a three-stranded beta-sheet. BIR is also found in other proteins known as BIR-domain-containing proteins (BIRPs), such as Survivin.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1720430095 180 RFLTYSMWPLSFL---SPAELARAGFYYIGPGDRVACFACGGKLSNWEPKDDAMSEHRRHFPHCPFLE 244
Cdd:pfam00653   1 RLATFENWPHSNKsppTPEELAEAGFYYTGTGDRVQCFYCGLELDGWEEGDDPWEEHKKHSPDCPFLK 68

Baculoviral inhibition of apoptosis protein repeat domain; Found in inhibitors of apoptosis proteins (IAPs) and other proteins. In higher eukaryotes, BIR domains inhibit apoptosis by acting as direct inhibitors of the caspase family of protease enzymes. In yeast, BIR domains are involved in regulating cytokinesis. This novel fold is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues and resembles a classical zinc finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1720430095  49 RMSTYSAFPRGVPVSERSLARAGFYYTGVNDKVKCFCCGLMLDNWKQGDSPVEKHRQFYPSCSFVQ 114
Cdd:cd00022     3 RLKTFKNWPISLKVTPEKLAEAGFYYTGRGDEVKCFFCGLELKNWEPGDDPWEEHKRWSPNCPFVL 68

UBA domain found in baculoviral IAP repeat-containing protein BIRC2, BIRC3 and similar proteins; The subfamily includes cellular inhibitor of apoptosis protein 1 (c-IAP1) and c-IAP2. c-IAPs function as ubiquitin E3 ligases that mediate the ubiquitination of the substrates involved in apoptosis, nuclear factor-kappaB (NF-kappaB)signaling, and oncogenesis. Unlike other apoptosis proteins (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 called 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 called 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 binds polyubiquitin (polyUb), a caspase activation and recruitment domain (CARD) that serves as a protein interaction surface, and a RING domain at the carboxyl terminus that is required for ubiquitin ligase activity.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1720430095 385 MSTPVVKAALEMGFSRSLVRQTVQRQILATGENYRTVNDIVSVLLNA 431
Cdd:cd14394     1 MNTPVVKSALEMGFNRRLVKQTVQSKILTSGENYKTVNDLVSDLLSA 47

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 1720430095  480 CKVCMDR-EVSIVFIPCGHlVVCQECAPSL-----RKCPIC 514
Cdd:smart00184   1 CPICLEEyLKDPVILPCGH-TFCRSCIRKWlesgnNTCPIC 40

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
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1720430095 471 LRRLQEERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTFLS 527
Cdd:cd16713     1 LRRLQEERTCKVCMDKEVSIVFIPCGHLVVCTECAPSLRKCPICRATIKGTVRTFLS 57

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1720430095  261 THSARLRTFLYWPPSVPVQPEQLASAGFYYVDRNDDVKCFCCDGGLRCWEPGDDPWIEHAKWFPRCEFL 329
Cdd:smart00238   1 SEEARLKTFQNWPYNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFV 69

Baculoviral inhibition of apoptosis protein repeat; Domain found in inhibitor of apoptosis proteins (IAPs) and other proteins. Acts as a direct inhibitor of caspase enzymes.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1720430095  176 TEEARFLTYSMWP-LSFLSPAELARAGFYYIGPGDRVACFACGGKLSNWEPKDDAMSEHRRHFPHCPFLEN 245
Cdd:smart00238   1 SEEARLKTFQNWPyNSKCTPEQLAEAGFYYTGVGDEVKCFFCGGELDNWEPGDDPWEEHKKWSPNCPFVRN 71

Inhibitor of Apoptosis domain; BIR stands for 'Baculovirus Inhibitor of apoptosis protein Repeat'. It is found repeated in inhibitor of apoptosis proteins (IAPs), and in fact it is also known as IAP repeat. These domains characteriztically have a number of invariant residues, including 3 conserved cysteines and one conserved histidine that coordinate a zinc ion. They are usually made up of 4-5 alpha helices and a three-stranded beta-sheet. BIR is also found in other proteins known as BIR-domain-containing proteins (BIRPs), such as Survivin.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1720430095 180 RFLTYSMWPLSFL---SPAELARAGFYYIGPGDRVACFACGGKLSNWEPKDDAMSEHRRHFPHCPFLE 244
Cdd:pfam00653   1 RLATFENWPHSNKsppTPEELAEAGFYYTGTGDRVQCFYCGLELDGWEEGDDPWEEHKKHSPDCPFLK 68

Baculoviral inhibition of apoptosis protein repeat domain; Found in inhibitors of apoptosis proteins (IAPs) and other proteins. In higher eukaryotes, BIR domains inhibit apoptosis by acting as direct inhibitors of the caspase family of protease enzymes. In yeast, BIR domains are involved in regulating cytokinesis. This novel fold is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues and resembles a classical zinc finger.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1720430095  49 RMSTYSAFPRGVPVSERSLARAGFYYTGVNDKVKCFCCGLMLDNWKQGDSPVEKHRQFYPSCSFVQ 114
Cdd:cd00022     3 RLKTFKNWPISLKVTPEKLAEAGFYYTGRGDEVKCFFCGLELKNWEPGDDPWEEHKRWSPNCPFVL 68

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 1720430095 465 LSLEEQLRRLQEERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTFLS 527
Cdd:cd16714     2 ISTEEKLRRLQEEKLCKICMDRNISIVFIPCGHLVTCKQCAEALDKCPICCTVITFKQKIFMS 64

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 1720430095 477 ERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRG 516
Cdd:cd16510     1 EKLCKICMDREVNIVFLPCGHLVTCAQCAASLRKCPICRT 40

UBA domain 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 and c-IAP2, XIAP, 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 binds polyubiquitin (polyUb), and a RING domain at the carboxyl terminus that is required for ubiquitin ligase activity. c-IAPs contains an additional caspase activation and recruitment domain (CARD) between UBA and RING domains. CARD domain may serve as a protein interaction surface.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1720430095 388 PVVKAALEMGFSRSLVRQTVQRQILATGENYRTVNDIVSVLLNA 431
Cdd:cd14321     1 PVVQSALEMGFDRDRVRRAIERRLEETGRPFSTAEELVEAVLNA 44

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
                  ....*....|....*....|....*....|....*....|....*.
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTF 525
Cdd:cd16501     8 CVVCMDAPIDTVFLECGHLACCRLCSKRLRVCPICRQPISRVVRIF 53

RING finger, HC subclass, found in Arabidopsis thaliana MND1-interacting protein 1 (MIP1) and similar proteins; This subfamily includes Arabidopsis thaliana MIP1, RING finger protein 4 (RF4) and RING finger protein 298 (RF298). MIP1 interacts with MND1, HOP2 and XRI1. RF4 and RF298 are putative E3 ubiquitin-protein ligase that may mediate E2-dependent protein ubiquitination. Members of this subfamily contain a typical C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1720430095 477 ERTCKVCMDREVSIVFIPCGHLVVCQECA-----PSLRKCPICRGTIKGTVR 523
Cdd:cd23128     3 ERECVMCMEEERSVVFLPCAHQVVCSGCNdlhekKGMRECPSCRGEIQERIR 54

RING finger, HC subclass, found in Arabidopsis thaliana protein XB3 homolog 5 (XBAT35) and similar proteins; XBAT35, also known as ankyrin repeat domain and RING finger-containing protein XBAT35, or RING-type E3 ubiquitin transferase XBAT35, has no E3 ubiquitin-protein ligase activity observed when associated with the E2 enzyme UBC8 in vitro. It contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1720430095 479 TCKVCMDREVSIVFIPCGHLVVCQECAPSL----RKCPICRGTIKGTVRTF 525
Cdd:cd23129     4 ECVVCMDAPRDAVCVPCGHVAGCMSCLKALmqssPLCPICRAPVRQVIKVY 54

Modified RING finger, HC subclass (C3HC5-type), found in mitochondrial-anchored protein ligase (MAPL) and similar proteins; MAPL, also known as MULAN, mitochondrial ubiquitin ligase activator of NFKB 1, E3 SUMO-protein ligase MUL1, E3 ubiquitin-protein ligase MUL1, growth inhibition and death E3 ligase (GIDE), putative NF-kappa-B-activating protein 266, or RING finger protein 218 (RNF218), is a multifunctional mitochondrial outer membrane protein involved in several processes specific to metazoan (multicellular animal) cells, such as NF-kappaB activation, innate immunity and antiviral signaling, suppression of PINK1/parkin defects, mitophagy in skeletal muscle, and caspase-dependent apoptosis. MAPL contains a unique BAM (beside a membrane)/GIDE (growth inhibition death E3 ligase) domain and a C-terminal modified cytosolic C3HC5-type RING-HC finger which is distinguished from typical C3HC4-type RING-HC finger due to the existence of the additional cysteine residue in the middle portion of the RING finger domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQEC---APSLRKCPICRGTIK 519
Cdd:cd16648     4 CVICLSNPRSCVFLECGHVCSCIECyeaLPSPKKCPICRSFIK 46

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 1720430095 478 RTCKVCMDREVSIVFIPCGHLVVCQECAPSLR--KCPICR 515
Cdd:cd16649     1 GLCVVCLENPASVLLLPCRHLCLCEVCAKGLRgkTCPICR 40

RING finger, HC subclass, found in caspases-8 and -10-associated RING finger protein 1 (CARP1) and similar proteins; CARP1, also known as caspase regulator CARP1, FYVE-RING finger protein Momo, RING finger homologous to inhibitor of apoptosis protein (RFI), RING finger protein 34 (RNF34), or RING finger protein RIFF, is a nuclear protein that functions as a specific E3 ubiquitin ligase for the transcriptional coactivator PGC-1alpha, a master regulator of energy metabolism and adaptive thermogenesis in the brown fat cell which negatively regulates brown fat cell metabolism. It is preferentially expressed in esophageal, gastric, and colorectal cancers, suggesting a possible association with the development of digestive tract cancers. It regulates the p53 signaling pathway by degrading 14-3-3 sigma and stabilizing MDM2. CARP1 does not localize to membranes in the cell and is involved in the negative regulation of apoptosis, specifically targeting two initiator caspases, caspase 8 and caspase 10. CARP1 contains an N-terminal FYVE-like domain and a C-terminal C3HC4-type RING-HC finger domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1720430095 475 QEERTCKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICRGTIKGTVRTFLS 527
Cdd:cd16706     2 SDDNLCRICMDAVIDCVLLECGHMVTCTKCGKRMSECPICRQYVVRAVHVFKS 54

Modified RING finger, HC subclass (C3HC5-type), found in cell growth regulator with RING finger domain protein 1 (CGRRF1) and similar proteins; 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. CGRRF1 contains 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
                  ....*....|....*....|....*....|....*.
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPICR 515
Cdd:cd16787     3 CVVCQNAPVNRVLLPCRHACVCDECFKRLQRCPMCR 38

UBA domain found in Xenopus tropicalis baculoviral IAP repeat-containing protein BIRC7, BIRC71A and similar proteins; X. tropicalis BIRC7, also called E3 ubiquitin-protein ligase EIAP, embryonic/Egg IAP (xEIAP/XLX), inhibitor of apoptosis (IAP)-like protein, XIAP homolog XLX, is a weak apoptosis inhibitor that exhibits caspase inhibition and autoubiquitylation. It is uniquely modified by MAPK- and Cdc2/Cyclin B-dependent phosphorylation during oocyte maturation. Its caspase-dependent cleavage is altered when it is phosphorylated. X. tropicalis BIRC7 contains two N-terminal baculoviral IAP repeats (BIRs) and a C-terminal RING domain. Based on sequence homology, it also harbors a ubiquitin-associated (UBA) domain which is not detected in human BIRC7.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1720430095 388 PVVKAALEMGFSRSLVRQTVQRQILATGENYRTVNDIVSVLLNA 431
Cdd:cd14396     1 SVVQAVLQMGFDQSLVESLVQNKYLLTGPAYTSVSQLVSDLLQE 44

UBA domain found in E3 ubiquitin-protein ligase XIAP, baculoviral IAP repeat-containing protein 8 (BIRC8) and similar proteins; XIAP, also called 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) pathway, the nuclear factor-kappaB (NF-kappaB) pathway, and the transforming growth factor-beta (TGF-beta) pathway. Moreover, XIAP can regulate copper homeostasis through interacting with MURR1. BIRC8, also called inhibitor of apoptosis-like protein 2 (IAP-like protein 2 or 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 RING domain at the carboxyl terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1720430095 384 MMSTPVVKAALEMGFSRSLVRQTVQRQILATGENYRTVNDIVSVLLNA 431
Cdd:cd14395     1 ILQNPLVQEAIRMGFSFKEIKKIMEEKLKTSGSNYTSLEVLVADLVSA 48

second RING finger, HC subclass, found in mind bomb 2 (MIB2) and similar proteins; MIB2, also known as novel zinc finger protein (Novelzin), putative NF-kappa-B-activating protein 002N, skeletrophin, or zinc finger ZZ type with ankyrin repeat domain protein 1, is a large, multi-domain E3 ubiquitin-protein ligase that promotes ubiquitination of the cytoplasmic tails of Notch ligands. Especially, it promotes Delta ubiquitylation and endocytosis in Notch activation. Overexpression of MIB2, activates NF-kappaB and interferon-stimulated response element (ISRE) reporter activity. Moreover, MIB2 acts as a novel component of the activated B-cell CLL/lymphoma 10 (BCL10) complex and controls BCL10-dependent NF-kappaB activation. It also functions as a founder myoblast-specific protein that regulates myoblast fusion and muscle stability. MIB2 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 two C3HC4-type RING-HC fingers. This model corresponds to the second RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1720430095 474 LQEERTCKVCMDREVSIVFiPCGHlVVCQECAPSLRKCPICRGTIKGTVRTFL 526
Cdd:cd16728     1 MEERITCPICIDNHIKLVF-QCGH-GSCIECSSALKACPICRQAIRERIQIFV 51

RING finger, HC subclass, found in Arabidopsis thaliana SP1-like protein 2 (SPL2) and similar proteins; SPL2, also known as RING-type E3 ubiquitin transferase SPL2, acts as an E3 ubiquitin-protein ligase that mediates E2-dependent protein ubiquitination. SPL2 contains a typical C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1720430095 479 TCKVCMDREVSIVFIPCGHLVVCQECAPSLR-----KCPICR 515
Cdd:cd23145     5 LCVVCLLRRRRVAFIECGHRVCCELCARRVTreanpRCPVCR 46

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 1720430095 479 TCKVCMDREVSIVFIPCGHlVVCQECAPSLR-----KCPIC 514
Cdd:cd16449     2 ECPICLERLKDPVLLPCGH-VFCRECIRRLLesgsiKCPIC 41

Modified RING finger, HC subclass (C3HC5-type), found in neuralized-like protein 1A (NEURL1A) and similar proteins; NEURL1A, also known as NEURL1, NEU, neuralized 1, or RING finger protein 67 (RNF67), is a mammalian homolog of the Drosophila neuralized (D-neu) protein. 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 the medulloblastoma. NEURL1A 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 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLRK-----CPICRGTIKGTVRTFLS 527
Cdd:cd16785     7 CTICYENAVDTVIYTCGHMCLCYACGLRLKKmlnacCPICRRAIKDIIKTYRS 59

RING finger, HC subclass, found in RNA-binding proteins of the evolutionarily-conserved MEX-3 family; MEX-3 phosphoproteins are found in vertebrates. They are mediators of post-transcriptional regulation in different organisms, and have been implicated in many core biological processes, including embryonic development, epithelial homeostasis, immune responses, metabolism, and cancer. They contain two K homology (KH) domains that provide RNA-binding capacity, and a C-terminal C3HC4-type RING-HC finger. They shuttle between the nucleus and the cytoplasm via the CRM1-dependent export pathway. The RNA-binding protein MEX-3 from nematode Caenorhabditis elegans is the founding member of the MEX-3 family. Due to the lack of a RING-HC finger, it is not included here.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1720430095 478 RTCKVCMDREVSIVFIPCGHLVVCQECAPSL-----RKCPICRGTIKGTVRTF 525
Cdd:cd16518     1 RDCVVCFESEVVAALVPCGHNLFCMECANRIceksdPECPVCHTPVTQAIRIF 53

first RING finger, HC subclass, found in mind bomb 2 (MIB2) and similar proteins; MIB2, also known as novel zinc finger protein (Novelzin), putative NF-kappa-B-activating protein 002N, skeletrophin, or zinc finger ZZ type with ankyrin repeat domain protein 1, is a large, multi-domain E3 ubiquitin-protein ligase that promotes ubiquitination of the cytoplasmic tails of Notch ligands. It promotes Delta ubiquitylation and endocytosis in Notch activation. Overexpression of MIB2 activates NF-kappaB and interferon-stimulated response element (ISRE) reporter activity. Moreover, MIB2 acts as a novel component of the activated B-cell CLL/lymphoma 10 (BCL10) complex and controls BCL10-dependent NF-kappaB activation. It also functions as a founder myoblast-specific protein that regulates myoblast fusion and muscle stability. MIB2 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 two C3HC4-type RING-HC fingers. This model corresponds to the first RING-HC finger.

                          10        20        30
                  ....*....|....*....|....*....|....*
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLRKCPIC 514
Cdd:cd16726     3 CLVCSELAALVRFEPCQHSIVCEECARRMKKCIKC 37

Prokaryotic RING finger family 4; RING finger family domain found sporadically in bacteria. The finger is fused to an N-terminal alpha-helical domain, ROT/Trove-like repeats and a C-terminal TerD domain. The architecture suggests a possible role in an RNA-processing complex.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1720430095 480 CKVCMDREVSIVFIPCGHLvVCQECAPS--LRKCPICRGTIKGT 521
Cdd:pfam14447   1 CVLCGRNGTVHALIPCGHL-VCRDCFDGsdFSACPICRRRIDAD 43

RING finger, HC subclass, found in RNA-binding protein MEX3D; MEX3D, also known as RING finger and KH domain-containing protein 1 (RKHD1), RING finger protein 193 (RNF193), or TINO, is an RNA-binding phosphoprotein that controls the stability of the transcripts coding for the anti-apoptotic protein BCL-2, and negatively regulates BCL-2 in HeLa cells. MEX3D 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, MEX3D shuttles between the nucleus and the cytoplasm via the CRM1-dependent export pathway.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1720430095 478 RTCKVCMDREVSIVFIPCGHLVVCQECA-----PSLRKCPICRGTIKGTVRTF 525
Cdd:cd16723    11 RECVVCFESEVIAALVPCGHNLFCMECAiricgKSEPECPACHTPATQAIHIF 63

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
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1720430095 475 QEERTCKVCMDREVSIVFIPCGHLVVCQECAPSL-------RKCPICRGTIKGTV 522
Cdd:cd16788     3 RDKKKCVICQDQSKTVLILPCRHMCLCRQCANILlqqpvyrRNCPLCRTMILQTL 57

RING finger, HC subclass, found in RING domain ligase RGLG1, RGLG2 and similar proteins from plant; RGLG1 is a ubiquitously expressed E3 ubiquitin-protein ligase that interacts with UBC13 and, together with UBC13, catalyzes the formation of K63-linked polyubiquitin chains, which is involved in DNA damage repair. RGLG1 mediates the formation of canonical, K48-linked polyubiquitin chains that target proteins for degradation. It also regulates apical dominance by acting on the auxin transport proteins abundance. RGLG1 has overlapping functions with its closest sequelog, RGLG2. They both function as RING E3 ligases that interact with ethylene response factor 53 (ERF53) in the nucleus and negatively regulate the plant drought stress response. Members of this subfamily contain a Von Willebrand factor type A (vWA) domain and a C3HC4-type RING-HC finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1720430095 476 EERTCKVCMDREVSIVFiPCGHLVvCQECAPSLRKCPICRGTIKGTVRTF 525
Cdd:cd16729     1 DDQLCPICLSNPKDMAF-GCGHQT-CCECGQSLTHCPICRQPITTRIKLY 48

RING finger, HC subclass, found in Casitas B-lineage lymphoma (Cbl) proteins; The Cbl adaptor protein family contains a small class of RING-type E3 ubiquitin ligases with oncogenic activity, which is represented by three mammalian members, c-Cbl, Cbl-b and Cbl-c, as well as two invertebrate Cbl-family proteins, D-Cbl in Drosophila and Sli-1 in C. elegans. Cbl proteins function as potent negative regulators of various signaling cascades in a wide range of cell types. They play roles in ubiquitinating activated tyrosine kinases and targeting them for degradation. D-Cbl associates with the Drosophila epidermal growth factor receptor (EGFR) and overexpression of D-Cbl in the eye of Drosophila embryos inhibits EGFR-dependent photoreceptor cell development. Sli-1 is a negative regulator of the Let-23 receptor tyrosine kinase, an EGFR homolog, in vulva development. Cbl proteins in this subfamily consist of a highly conserved N-terminal half that includes a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain) and a C3HC4-type RING-HC finger, both of which are required for Cbl-mediated downregulation of RTKs, and a divergent C-terminal region.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1720430095 480 CKVCMDREVSIVFIPCGHLvVCQECAPSLRK-----CPICR 515
Cdd:cd16502     4 CKICAENDKDVRIEPCGHL-LCTPCLTSWQDsdgqtCPFCR 43

Modified RING finger, HC subclass (C2H2C4-type), found in protein MDM4 and similar proteins; MDM4, also known as double minute 4 protein (Hdm4), MDM2-like p53-binding protein, protein MDMX, HDMX, or p53-binding protein MDM4, exerts its oncogenic activity predominantly by binding p53 tumor suppressor and blocking its transcriptional activity. MDM4 is phosphorylated and destabilized in response to DNA damage stress. It can also be specifically dephosphorylated by directly interacting with protein phosphatase 1 (PP1), which may increase its stability and thus inhibit p53 activity. Meanwhile, MDM4 has a p53-independent role in tumorigenesis and cell growth regulation. MDM4 contains an N-terminal p53-binding domain and a C-terminal modified C2H2C4-type RING-HC finger responsible for its hetero-oligomerization, which is crucial for the suppression of P53 activity during embryonic development and the recruitment of E2 ubiquitin-conjugating enzymes. MDM4 also harbors a RanBP2-type zinc finger (zf-RanBP2) domain near the central acidic region.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1720430095 480 CKVCM--DREVSIVFIPCGHLVVCQECAPSLRK----CPICRGTIKGTVRTFLS 527
Cdd:cd16784     6 CSLCQkrPRNGNIVHGRTAHLVTCFHCARRLKKagapCPVCKKEIQMVIKIFIA 59

RING finger, HC subclass, found in E3 ubiquitin-protein ligase Cbl and similar proteins; Cbl, also known as Casitas B-lineage lymphoma proto-oncogene, proto-oncogene c-Cbl, RING finger protein 55 (RNF55), or signal transduction protein Cbl, is a multi-domain protein that acts as a key negative regulator of various receptor and non-receptor tyrosine kinase signaling. It contains a tyrosine kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain), a proline-rich domain, a C3HC4-type RING-HC finger, and an ubiquitin-associated (UBA) domain. TKB is responsible for the interactions with many tyrosine kinases, such as the colony-stimulating factor-1 (CSF-1) receptor, Syk/ZAP-70, and Src-family of protein tyrosine kinases. The proline-rich domain can recruit proteins with a SH3 domain. Moreover, Cbl functions as an E3 ubiquitin ligase that can bind ubiquitin-conjugating enzymes (E2s) through the RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1720430095 480 CKVCMDREVSIVFIPCGHLvVCQECAPSLRK-----CPICRGTIKGT 521
Cdd:cd16708    24 CKICAENDKDVKIEPCGHL-MCTSCLTSWQEsegqgCPFCRCEIKGT 69

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 1720430095 480 CKVCMDREVSIVFIPCGHLvVCQECAPSLRK-----CPICRGTIKGT 521
Cdd:cd16709    23 CKICAENDKDVKIEPCGHL-MCTSCLTAWQEsdgqgCPFCRCEIKGT 68

RING finger, HC subclass, found in yeast Bre1 and its homologs from eukaryotes; Bre1 is an E3 ubiquitin-protein ligase that catalyzes monoubiquitination of histone H2B in concert with the E2 ubiquitin-conjugating enzyme, Rad6. The Rad6-Bre1-mediated histone H2B ubiquitylation modulates the formation of double-strand breaks (DSBs) during meiosis in yeast. it is also required, indirectly, for the methylation of histone 3 on lysine 4 (H3K4) and 79. RNF20, also known as BRE1A and RNF40, also known as BRE1B, are the mammalian homologs of Bre1. They work together to form a heterodimeric Bre1 complex that facilitate the K120 monoubiquitination of histone H2B (H2Bub1), a DNA damage-induced histone modification that is crucial for recruitment of the chromatin remodeler SNF2h to DNA double-strand break (DSB) damage sites. Moreover, the Bre1 complex acts as a tumor suppressor, augmenting expression of select tumor suppressor genes and suppressing select oncogenes. Deficiency in the mammalian histone H2B ubiquitin ligase Bre1 leads to replication stress and chromosomal instability. All subfamily members contain a C3HC4-type RING-HC finger at its C-terminus.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1720430095 472 RRLQEERTCKVCMDREVSIVFIPCGHlVVCQECAPSL-----RKCPIC 514
Cdd:cd16499     1 KDLRELLKCSVCNDRFKDVIITKCGH-VFCNECVQKRletrqRKCPGC 47

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
                  ....*....|....*....|....*....|....*....|
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLR----KCPICR 515
Cdd:cd16817     7 CVVCLSDVRDTLILPCRHLCLCNACADTLRyqanNCPICR 46

Modified RING finger, HC subclass (C3HC5-type), found in mahogunin RING finger protein 1 (MGRN1) and similar proteins; 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. MGRN1 interacts with cytosolic prion proteins (PrPs) that are linked with neurodegeneration. It also interacts with expanded polyglutamine proteins, and suppresses misfolded polyglutamine aggregation and cytotoxicity. Moreover, MGRN1 inhibits melanocortin receptor signaling by competition with Galphas, suggesting a novel pathway for melanocortin signaling from the cell surface to the nucleus. Furthermore, MGRN1 interacts with and ubiquitylates TSG101, a key component of the endosomal sorting complex required for transport (ESCRT)-I, and regulates endosomal trafficking. A null mutation in the gene encoding MGRN1 causes spongiform neurodegeneration, suggesting a link between dysregulation of endosomal trafficking and spongiform neurodegeneration. MGRN1 contains a modified C3HC5-type RING-HC finger, a conserved PSAP motif necessary for interaction between MGRN1 and TSG101. In addition, MGRN1 harbors a functionally uncharacterized region, as known as the 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
                  ....*....|....*....|....*....|....*....|
gi 1720430095 480 CKVCMDREVSIVFIPCGHLVVCQECAPSLR----KCPICR 515
Cdd:cd16816    11 CVVCLSDLRDTLILPCRHLCLCNSCADTLRyqanNCPICR 50

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.

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gi 1720430095 474 LQEERTCKVCMDREVSIVFIPCGHlVVCQECAPSLRK---------CPICRGTIK 519
Cdd:cd16598     1 LEEEVTCSICLDYLRDPVTIDCGH-NFCRSCITDYCPisggherpvCPLCRKPFK 54