BRcat (benign-catalytic) and Rcat (required-for-catalysis) domains, part of the RBR (RING1-BRcat-Rcat) domain; The RBR family of RING-type E3 ligases are characterized by containing an RBR (RING1-BRcat-Rcat) domain, which was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. It is composed of an extended RING domain (RING1) followed by an in-between RING (IBR) domain and the catalytic domain, which is structurally an IBR domain but is commonly designated as RING2. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBRs has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis), where the IBR and RING2 domains have been renamed as BRcat and Rcat domains, respectively. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. The BRcat domain adopts the same fold as the Rcat domain while lacking the catalytic cysteine residue and ubiquitination activity. RBR family members play roles in protein quality control and can indirectly regulate transcription. Evidence suggests that RBR proteins are often parts of cullin-containing ubiquitin ligase complexes.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 471202355 191 QWIKQNTKICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMA------DYnsNHWSTNTTGCRQF 247
Cdd:cd20354    7 EWLEKNSKPCPGCGTLIEKIDGCNKMTCtKCRTYFCWLCLKvlsrtnPY--SHFSDPNSPCFNR 68

BRcat (benign-catalytic) domain, part of the RBR (RING1-BRcat-Rcat) domain; The RBR family of RING-type E3 ligases are characterized by containing an RBR domain, which was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. It is composed of an extended RING domain (RING1) followed by an in-between RING (IBR) domain and the catalytic domain, which is structurally an IBR domain but is commonly designated as RING2. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently, where the IBR and RING2 domains have been renamed as BRcat and Rcat domains, respectively. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. The BRcat domain adopts the same fold as the Rcat domain while lacking the catalytic cysteine residue and ubiquitination activity. RBR family members play roles in protein quality control and can indirectly regulate transcription. Evidence suggests that RBR proteins are often parts of cullin-containing ubiquitin ligase complexes. The model corresponds to the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 471202355 145 DKGMAACVYCEYTFCRECLEPWHVGRTCEQW 175
Cdd:cd20335   23 DGPRVTCPSCGTSFCFKCKEEWHEGLTCEEY 53

Rcat domain found in RING finger protein 14 (RNF14); RNF14, also called androgen receptor (AR)-associated protein 54 (ARA54), HFB30, or Triad2 protein, is an RBR-type E3 ubiquitin-protein ligase that is highly expressed in the testis and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3). Its differential localization may play an important role in testicular development and spermatogenesis in humans. RNF14 functions as a transcriptional regulator of mitochondrial and immune function in muscles. It is a ligand-dependent AR co-activator that enhances AR-dependent transcriptional activation. It also may participate in enhancing cell cycle progression and cell proliferation via induction of cyclin D1. Moreover, RNF14 is crucial for colon cancer cell survival. It acts as a new enhancer of the Wnt-dependent transcriptional outputs that acts at the level of the T-cell factor/lymphoid enhancer factor (TCF/LEF)-beta-catenin complex. RNF14 contains an N-terminal RWD domain, and a C-terminal RBR domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of RNF14 that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 471202355 191 QWIKQNTKICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMA------DYnsNHWSTNTTGCRQF 247
Cdd:cd20354    7 EWLEKNSKPCPGCGTLIEKIDGCNKMTCtKCRTYFCWLCLKvlsrtnPY--SHFSDPNSPCFNR 68

BRcat (benign-catalytic) domain, part of the RBR (RING1-BRcat-Rcat) domain; The RBR family of RING-type E3 ligases are characterized by containing an RBR domain, which was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. It is composed of an extended RING domain (RING1) followed by an in-between RING (IBR) domain and the catalytic domain, which is structurally an IBR domain but is commonly designated as RING2. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently, where the IBR and RING2 domains have been renamed as BRcat and Rcat domains, respectively. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. The BRcat domain adopts the same fold as the Rcat domain while lacking the catalytic cysteine residue and ubiquitination activity. RBR family members play roles in protein quality control and can indirectly regulate transcription. Evidence suggests that RBR proteins are often parts of cullin-containing ubiquitin ligase complexes. The model corresponds to the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 471202355 145 DKGMAACVYCEYTFCRECLEPWHVGRTCEQW 175
Cdd:cd20335   23 DGPRVTCPSCGTSFCFKCKEEWHEGLTCEEY 53

Rcat domain found in RING finger protein 14 (RNF14); RNF14, also called androgen receptor (AR)-associated protein 54 (ARA54), HFB30, or Triad2 protein, is an RBR-type E3 ubiquitin-protein ligase that is highly expressed in the testis and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3). Its differential localization may play an important role in testicular development and spermatogenesis in humans. RNF14 functions as a transcriptional regulator of mitochondrial and immune function in muscles. It is a ligand-dependent AR co-activator that enhances AR-dependent transcriptional activation. It also may participate in enhancing cell cycle progression and cell proliferation via induction of cyclin D1. Moreover, RNF14 is crucial for colon cancer cell survival. It acts as a new enhancer of the Wnt-dependent transcriptional outputs that acts at the level of the T-cell factor/lymphoid enhancer factor (TCF/LEF)-beta-catenin complex. RNF14 contains an N-terminal RWD domain, and a C-terminal RBR domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of RNF14 that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 471202355 191 QWIKQNTKICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMA------DYnsNHWSTNTTGCRQF 247
Cdd:cd20354    7 EWLEKNSKPCPGCGTLIEKIDGCNKMTCtKCRTYFCWLCLKvlsrtnPY--SHFSDPNSPCFNR 68

Rcat domain found in E3 ubiquitin-protein ligase ARI7 and similar proteins; This subfamily contains probable RBR-type E3 ubiquitin-protein ligases (EC 2.3.2.31) including Arabidopsis thaliana ARI5, ARI6, ARI7, and ARI8, as well as Dictyostelium discoideum RbrA (also called Ariadne-like ubiquitin ligase). They may function as part of E3 complexes, which accept ubiquitin from E2 ubiquitin-conjugating enzymes and then transfer it to substrates. RbrA may be required for normal cell-type proportioning and cell sorting during multicellular development, and is also necessary for spore cell viability. Members of this subfamily contain an RBR domain that was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of ARI7-like proteins that are essential for RBR E3 ligase activity and adopt the same fold as the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 471202355 196 NTKICPRCKNPIQKNGGCNHMTCR--CGHQFCWLCMADY 232
Cdd:cd22583    1 NTKPCPKCKRPIEKNQGCMHMTCSppCKHEFCWLCLGPW 39

Rcat domain found in E3 ubiquitin-protein ligase ARI1 and similar proteins; This subfamily contains probable RBR-type E3 ubiquitin-protein ligases (EC 2.3.2.31) including Arabidopsis thaliana ARI1, ARI2, and ARI3. They may function as part of E3 complexes, which accept ubiquitin from E2 ubiquitin-conjugating enzymes and then transfer it to substrates. Members of this subfamily contain an RBR domain that was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of ARI1-like proteins that are essential for RBR E3 ligase activity and adopt the same fold as the BRcat domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 471202355 196 NTKICPRCKNPIQKNGGCNHMTCRCGHQFCWLCMADYNSNHWSTNTTG 243
Cdd:cd22586    3 NTKLCPKCSKPVEKNGGCNLVTCRCGQHFCWLCGAATGRDHTWESIAG 50

Rcat domain found in two RING fingers and DRIL [double RING finger linked] 1 (TRIAD1); TRIAD1, also called ariadne-2 (ARI-2), protein ariadne-2 homolog, Ariadne RBR E3 ubiquitin protein ligase 2 (ARIH2), or UbcM4-interacting protein 48, is an RBR-type E3 ubiquitin-protein ligase that catalyzes the formation of polyubiquitin chains linked via lysine-48 as well as lysine-63 residues. Its auto-ubiquitylation can be catalyzed by the E2 conjugating enzyme UBCH7. TRIAD1 has been implicated in hematopoiesis, specifically in myelopoiesis, as well as in embryogenesis. It functions as a regulator of endosomal transport, and is required for the proper function of multivesicular bodies. It also acts as a novel ubiquitination target for proteasome-dependent degradation by murine double minute 2 (MDM2). As a proapoptotic protein, TRIAD1 promotes p53 activation, and inhibits MDM2-mediated p53 ubiquitination and degradation. Furthermore, TRIAD1 can inhibit the ubiquitination and proteasomal degradation of growth factor independence 1 (Gfi1), a transcriptional repressor essential for the function and development of many different hematopoietic lineages. TRIAD1 contains an RBR domain that was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of TRIAD1 that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|
gi 471202355 196 NTKICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMADYNS 234
Cdd:cd20360    2 HTKDCPKCHVCIEKNGGCNHMQCsKCKHEFCWMCLGDWKT 41

Rcat domain found in an uncharacterized subfamily of RBR proteins; This subfamily contains uncharacterized members of the RBR family, including Arabidopsis thaliana mutator-like transposase and hypothetical protein At2g19610/F3P11.21. The RBR family of RING-type E3 ligases are characterized by containing a RBR domain, which was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. It is composed of an extended RING domain (RING1) followed by an in-between RING (IBR) domain and the catalytic domain, which is structurally an IBR domain but is commonly designated RING2. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been corrected as RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently, where the IBR and RING2 domains have been renamed as BRcat and Rcat domains, respectively. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. RBR family members play roles in protein quality control and can indirectly regulate transcription. Evidence suggests that RBR proteins are often parts of cullin-containing ubiquitin ligase complexes. This model corresponds to the Rcat domain that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|.
gi 471202355 198 KICPRCKNPIQKNGGCNHMTCRCGHQFCWLC 228
Cdd:cd22584    3 RRCPQCGHMVELSEGCNHMTCRCGYEFCYLC 33

Rcat domain found in cullin-9 (CUL-9) and similar proteins; CUL-9, also called UbcH7-associated protein 1 (H7-AP1), p53-associated parkin-like cytoplasmic protein, or PARC, is a cytoplasmic RBR-type E3 ubiquitin-protein ligase that function as a tumor suppressor and promotes p53-dependent apoptosis. It mediates the ubiquitination and degradation of cytosolic cytochrome c to promote survival in neurons and cancer cells. It is also a critical downstream effector of the 3M complex in the maintenance of microtubules and genome integrity. Moreover, CUL-9, together with CUL-7, forms homodimers and heterodimers, as well as some atypical cullin RING ligase complexes, which may exhibit ubiquitin ligase activity. CUL-9 contains a CPH domain (conserved in Cul7, PARC, and HERC2 proteins), a DOC (DOC1/APC10) domain, cullin homology domains linked with E3 ligase function, and a C-terminal RBR domain previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of CUL-9 that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 471202355 197 TKICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMADYNSNH 236
Cdd:cd20359    7 SKRCPSCQAQIEKNEGCLHMTCaKCNHGFCWRCLKPWKPTH 47

Rcat domain found in the RNF144 protein subfamily; The RNF144 subfamily includes RNF144A and RNF144B, which are transmembrane (TM) domain-containing RBR-type E3 ubiquitin-protein ligases. RNF144A, also called UbcM4-interacting protein 4 (UIP4), or ubiquitin-conjugating enzyme 7-interacting protein 4, targets DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and thus promotes DNA damage-induced cell apoptosis. It is transcriptionally repressed by metastasis-associated protein 1 (MTA1) and inhibits MTA1-driven cancer cell migration and invasion. RNF144B, also called PIR2, IBR domain-containing protein 2 (IBRDC2), or p53-inducible RING finger protein (p53RFP), induces p53-dependent but caspase-independent apoptosis. It interacts with E2 ubiquitin-conjugating enzymes UbcH7 and UbcH8, but not with UbcH5. It is involved in ubiquitination and degradation of p21, a p53 downstream protein promoting growth arrest and antagonizing apoptosis, suggesting a role in switching a cell from p53-mediated growth arrest to apoptosis. Moreover, RNF144B regulates the levels of Bax, a pro-apoptotic protein from the Bcl-2 family, and protects cells from unprompted Bax activation and cell death. It also regulates epithelial homeostasis by mediating degradation of p21WAF1 and p63. Both RNF144A and RNF144B contain an RBR domain followed by a potential single-TM domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of the RNF144 protein subfamily that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|....
gi 471202355 198 KICPRCKNPIQKNGGCNHMTC-RCGHQFCWLCMA 230
Cdd:cd20352    6 KRCPMCHVPIERDEGCAQMMCkNCKHVFCWYCLA 39

Rcat domain found in RING finger protein 216 (RNF216); RNF216, also called Triad domain-containing protein 3 (Triad3A), ubiquitin-conjugating enzyme 7-interacting protein 1, or zinc finger protein inhibiting NF-kappa-B (ZIN), is an RBR-type E3 ubiquitin-protein ligase that interacts with several components of the Toll-like receptor (TLR) signaling and promotes their proteolytic degradation. It negatively regulates the RIG-I RNA sensing pathway through Lys48-linked, ubiquitin-mediated degradation of the tumor necrosis factor receptor-associated factor 3 (TRAF3) adapter following RNA virus infection. It also controls ubiquitination and proteasomal degradation of receptor-interacting protein 1 (RIP1), a serine/threonine protein kinase that is critically involved in tumor necrosis factor receptor-1 (TNF-R1)-induced NF-kappa B activation, following disruption of Hsp90 binding. Moreover, RNF216 is involved in inflammatory diseases by strongly inhibiting autophagy in macrophages. It interacts with and ubiquitinates BECN1, a key regulator in autophagy, thereby contributing to BECN1 degradation. It regulates synaptic strength by ubiquitination of Arc, resulting in its rapid proteasomal degradation. It is also a key negative regulator of sustained 2DL4/KIR2DL4 (killer cell Ig-like receptor with two Ig-like domains and a long cytoplasmic domain 4)-mediated NF-kappaB signaling from internalized 2DL4, which functions by promoting ubiquitylation and degradation of endocytosed receptor from early endosomes. Furthermore, RNF216 interacts with human immunodeficiency virus type 1 (HIV-1) virion infectivity factor (Vif) protein, which is essential for the productive infection of primary human CD4 T lymphocytes and macrophages. Mutations in RNF216 may result in Gordon Holmes syndrome, a condition defined by hypogonadotropic hypogonadism and cerebellar ataxia, as well as in autosomal recessive Huntington-like disorder. RNF216 contains an RBR domain that was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. The family corresponds to the Rcat domain of RNF216 that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20
                 ....*....|....*....|....*....
gi 471202355 200 CPRCKNPIQKNGGCNHMTCRCGHQFCWLC 228
Cdd:cd20353   12 CPKCKTKFIKSEGCNKMTCRCGAKMCYIC 40

RING finger, HC subclass, found in two RING fingers and DRIL [double RING finger linked] 1 (TRIAD1); TRIAD1, also known as ariadne-2 (ARI-2), protein ariadne-2 homolog, Ariadne RBR E3 ubiquitin protein ligase 2 (ARIH2), or UbcM4-interacting protein 48, is an RBR-type E3 ubiquitin-protein ligase that catalyzes the formation of polyubiquitin chains linked via lysine-48, as well as lysine-63 residues. Its auto-ubiquitylation can be catalyzed by the E2 conjugating enzyme UBCH7. TRIAD1 has been implicated in hematopoiesis, specifically in myelopoiesis, as well as in embryogenesis. It functions as a regulator of endosomal transport and is required for the proper function of multivesicular bodies. It also acts as a novel ubiquitination target for proteasome-dependent degradation by murine double minute 2 (MDM2). As a proapoptotic protein, TRIAD1 promotes p53 activation, and inhibits MDM2-mediated p53 ubiquitination and degradation. Furthermore, TRIAD1 can inhibit the ubiquitination and proteasomal degradation of growth factor independence 1 (Gfi1), a transcriptional repressor essential for the function and development of many different hematopoietic lineages. TRIAD1 contains an RBR domain that was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been corrected as RING-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR (RING1-BRcat-Rcat) domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase function to facilitate the ubiquitination reaction. This model corresponds to the RING domain, a C3HC4-type RING-HC finger required for RBR-mediated ubiquitination.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 471202355  45 CSVCMEDVPFDDTYINVCGHRFCKSCVRDSIKYQMKQ-TWEKVHCQEGGC 93
Cdd:cd16773    3 CGVCCEDVPKDELFSLACGHYFCNDCWKQYLTVKIKDgVSTGIECMAPDC 52

BRcat (benign-catalytic) and Rcat (required-for-catalysis) domains, part of the RBR (RING1-BRcat-Rcat) domain; The RBR family of RING-type E3 ligases are characterized by containing an RBR (RING1-BRcat-Rcat) domain, which was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. It is composed of an extended RING domain (RING1) followed by an in-between RING (IBR) domain and the catalytic domain, which is structurally an IBR domain but is commonly designated as RING2. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBRs has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis), where the IBR and RING2 domains have been renamed as BRcat and Rcat domains, respectively. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. The BRcat domain adopts the same fold as the Rcat domain while lacking the catalytic cysteine residue and ubiquitination activity. RBR family members play roles in protein quality control and can indirectly regulate transcription. Evidence suggests that RBR proteins are often parts of cullin-containing ubiquitin ligase complexes.

                         10        20        30
                 ....*....|....*....|....*....|....
gi 471202355 196 NTKICPRCKNPIQKNGGCNHMTCR-CGHQFCWLC 228
Cdd:cd14799    1 NTKWCPKCHFGFEKERGCMHATCPqCRQEFCWRC 34

Rcat domain found in RING finger protein 144A (RNF144A); RNF144A, also called UbcM4-interacting protein 4 (UIP4), or ubiquitin-conjugating enzyme 7-interacting protein 4, is a transmembrane (TM) domain-containing RBR-type E3 ubiquitin-protein ligase that targets DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and thus promotes DNA damage-induced cell apoptosis. It is transcriptionally repressed by metastasis-associated protein 1 (MTA1) and inhibits MTA1-driven cancer cell migration and invasion. RNF144A contains an RBR domain followed by a potential single-TM domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase functions to facilitate the ubiquitination reaction. This model corresponds to the Rcat domain of RNF144A that is essential for RBR E3 ligase activity and adopts the same fold as the BRcat domain.

                         10        20        30
                 ....*....|....*....|....*....|....*....
gi 471202355 198 KICPRCKNPIQKNGGCNHMTCR-CGHQFCWLCMADYNSN 235
Cdd:cd20368    7 KRCPKCKVYIERDEGCAQMMCKnCKHAFCWYCLESLDDD 45

BRcat domain found in RING finger protein 14 (RNF14); RNF14, also called androgen receptor (AR)-associated protein 54 (ARA54), HFB30, or Triad2 protein, is an RBR-type E3 ubiquitin-protein ligase that is highly expressed in the testis and interacts with class III E2s (UBE2E2, UbcH6, and UBE2E3). Its differential localization may play an important role in testicular development and spermatogenesis in humans. RNF14 functions as a transcriptional regulator of mitochondrial and immune function in muscles. It is a ligand-dependent AR co-activator that enhances AR-dependent transcriptional activation. It may also participate in enhancing cell cycle progression and cell proliferation via induction of cyclin D1. Moreover, RNF14 is crucial for colon cancer cell survival. It acts as a new enhancer of the Wnt-dependent transcriptional outputs that acts at the level of the T-cell factor/lymphoid enhancer factor (TCF/LEF)-beta-catenin complex. RNF14 contains an N-terminal RWD domain, and a C-terminal RBR domain. The RBR domain was previously known as RING-BetweenRING-RING domain or TRIAD [two RING fingers and a DRIL (double RING finger linked)] domain. Based on current understanding of the structural biology of RBR ligases, the nomenclature of RBR has been changed to RING1-BRcat (benign-catalytic)-Rcat (required-for-catalysis) recently. The RBR domain uses an auto-inhibitory mechanism to modulate ubiquitination activity, as well as a hybrid mechanism that combines aspects from both RING and HECT E3 ligase function to facilitate the ubiquitination reaction. This model corresponds to the BRcat domain of RNF14 that adopts the same fold as the Rcat domain while lacking the catalytic cysteine residue and ubiquitination activity.

                         10        20
                 ....*....|....*....|....*.
gi 471202355 148 MAACVYCEYTFCRECLEPWHVGRTCE 173
Cdd:cd20341   27 LGICPSCNYAFCTLCRETYHGVSPCK 52