The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yue Xiong - One of the best experts on this subject based on the ideXlab platform.
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BTB protein Keap1 targets antioxidant transcription factor Nrf2 for ubiquitination by the Cullin 3-Roc1 ligase
2016Co-Authors: Manabu Furukawa, Yue XiongAbstract:The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual Cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other Cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic seques-tration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF
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crl4s the cul4 ring e3 ubiquitin ligases
Trends in Biochemical Sciences, 2009Co-Authors: Sarah Jackson, Yue XiongAbstract:The evolutionarily conserved Cullin family proteins can assemble as many as 400 distinct E3 ubiquitin ligase complexes that regulate diverse cellular pathways. CUL4, one of three founding Cullins conserved from yeast to humans, uses a large β-propeller protein, DDB1, as a linker to interact with a subset of WD40 proteins that serve as substrate receptors, forming as many as 90 E3 complexes in mammals. Many CRL4 complexes are involved in chromatin regulation and are frequently hijacked by different viruses.
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ectromelia virus btb kelch proteins evm150 and evm167 interact with Cullin 3 based ubiquitin ligases
Virology, 2008Co-Authors: Brianne A. Wilton, Manabu Furukawa, Yue Xiong, Nicholas Van Buuren, Stephanie Campbell, Robyn Garneau, Michele BarryAbstract:Cellular proteins containing BTB and kelch domains have been shown to function as adapters for the recruitment of substrates to Cullin-3-based ubiquitin ligases. Poxviruses are the only family of viruses known to encode multiple BTB/kelch proteins, suggesting that poxviruses may modulate the ubiquitin pathway through interaction with Cullin-3. Ectromelia virus encodes four BTB/kelch proteins and one BTB-only protein. Here we demonstrate that two of the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interacted with Cullin-3. Similar to cellular BTB proteins, the BTB domain of EVM150 and EVM167 was necessary and sufficient for Cullin-3 interaction. During infection, EVM150 and EVM167 localized to discrete cytoplasmic regions, which co-localized with Cullin-3. Furthermore, EVM150 and EVM167 co-localized and interacted with conjugated ubiquitin, as demonstrated by confocal microscopy and co-immunoprecipitation. Our findings suggest that the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interact with Cullin-3 potentially functioning to recruit unidentified substrates for ubiquitination.
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characterization of arabidopsis and rice dwd proteins and their roles as substrate receptors for cul4 ring e3 ubiquitin ligases
The Plant Cell, 2008Co-Authors: Jaehoon Lee, Yue Xiong, William Terzaghi, Giuliana Gusmaroli, Jeanbenoit Charron, Hyejin Yoon, Haodong Chen, Xing Wang DengAbstract:A subset of WD40 proteins that contain a DWD motif (for DDB1 binding WD40) is reported to act as substrate receptors for DDB1-CUL4-ROC1 (for Damaged DNA Binding 1-Cullin 4-Regulator of Cullins 1) based E3 ubiquitin ligases in humans. Here, we report 85 Arabidopsis thaliana and 78 rice (Oryza sativa) proteins containing the conserved 16-amino acid DWD motif. We show by yeast two-hybrid and in vivo coimmunoprecipitation that 11 Arabidopsis DWD proteins directly interact with DDB1 and thus may serve as substrate receptors for the DDB1-CUL4 machinery. We further examine whether the DWD protein PRL1 (for Pleiotropic Regulatory Locus 1) may act as part of a CUL4-based E3 ligase. PRL1 directly interacts with DDB1, and prl1 and cul4cs mutants exhibited similar phenotypes, including altered responses to a variety of stimuli. Moreover, AKIN10 (for Arabidopsis SNF1 Kinase Homolog 10) was degraded more slowly in cell extracts of prl1 and cul4cs than in cell extracts of the wild type. Thus, both genetic and biochemical analyses support the conclusion that PRL1 is the substrate receptor of a CUL4-ROC1-DDB1-PRL1 E3 ligase involved in the degradation of AKIN10. This work adds a large new family to the current portfolio of plant E3 ubiquitin ligases.
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btb protein keap1 targets antioxidant transcription factor nrf2 for ubiquitination by the Cullin 3 roc1 ligase
Molecular and Cellular Biology, 2005Co-Authors: Manabu Furukawa, Yue XiongAbstract:The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual Cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other Cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic sequestration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF2 degradation.
Manabu Furukawa - One of the best experts on this subject based on the ideXlab platform.
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BTB protein Keap1 targets antioxidant transcription factor Nrf2 for ubiquitination by the Cullin 3-Roc1 ligase
2016Co-Authors: Manabu Furukawa, Yue XiongAbstract:The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual Cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other Cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic seques-tration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF
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ectromelia virus btb kelch proteins evm150 and evm167 interact with Cullin 3 based ubiquitin ligases
Virology, 2008Co-Authors: Brianne A. Wilton, Manabu Furukawa, Yue Xiong, Nicholas Van Buuren, Stephanie Campbell, Robyn Garneau, Michele BarryAbstract:Cellular proteins containing BTB and kelch domains have been shown to function as adapters for the recruitment of substrates to Cullin-3-based ubiquitin ligases. Poxviruses are the only family of viruses known to encode multiple BTB/kelch proteins, suggesting that poxviruses may modulate the ubiquitin pathway through interaction with Cullin-3. Ectromelia virus encodes four BTB/kelch proteins and one BTB-only protein. Here we demonstrate that two of the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interacted with Cullin-3. Similar to cellular BTB proteins, the BTB domain of EVM150 and EVM167 was necessary and sufficient for Cullin-3 interaction. During infection, EVM150 and EVM167 localized to discrete cytoplasmic regions, which co-localized with Cullin-3. Furthermore, EVM150 and EVM167 co-localized and interacted with conjugated ubiquitin, as demonstrated by confocal microscopy and co-immunoprecipitation. Our findings suggest that the ectromelia virus-encoded BTB/kelch proteins, EVM150 and EVM167, interact with Cullin-3 potentially functioning to recruit unidentified substrates for ubiquitination.
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btb protein keap1 targets antioxidant transcription factor nrf2 for ubiquitination by the Cullin 3 roc1 ligase
Molecular and Cellular Biology, 2005Co-Authors: Manabu Furukawa, Yue XiongAbstract:The concentrations and functions of many eukaryotic proteins are regulated by the ubiquitin pathway, which consists of ubiquitin activation (E1), conjugation (E2), and ligation (E3). Cullins are a family of evolutionarily conserved proteins that assemble by far the largest family of E3 ligase complexes. Cullins, via a conserved C-terminal domain, bind with the RING finger protein Roc1 to recruit the catalytic function of E2. Via a distinct N-terminal domain, individual Cullins bind to a protein motif present in multiple proteins to recruit specific substrates. Cullin 3 (Cul3), but not other Cullins, binds directly with BTB domains to constitute a potentially large number of BTB-CUL3-ROC1 E3 ubiquitin ligases. Here we report that the human BTB-Kelch protein Keap1, a negative regulator of the antioxidative transcription factor Nrf2, binds to CUL3 and Nrf2 via its BTB and Kelch domains, respectively. The KEAP1-CUL3-ROC1 complex promoted NRF2 ubiquitination in vitro and knocking down Keap1 or CUL3 by short interfering RNA resulted in NRF2 protein accumulation in vivo. We suggest that Keap1 negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the CUL3-ROC1 ligase and subsequent degradation by the proteasome. Blocking NRF2 degradation in cells expressing both KEAP1 and NRF2 by either inhibiting the proteasome activity or knocking down Cul3, resulted in NRF2 accumulation in the cytoplasm. These results may reconcile previously observed cytoplasmic sequestration of NRF2 by KEAP1 and suggest a possible regulatory step between KEAP1-NRF2 binding and NRF2 degradation.
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targeting of protein ubiquitination by btb Cullin 3 roc1 ubiquitin ligases
Nature Cell Biology, 2003Co-Authors: Manabu Furukawa, Christoph H Borchers, Yue XiongAbstract:The concentrations and functions of many cellular proteins are regulated by the ubiquitin pathway. Cullin family proteins bind with the RING-finger protein Roc1 to recruit the ubiquitin-conjugating enzyme (E2) to the ubiquitin ligase complex (E3). Cul1 and Cul7, but not other Cullins, bind to an adaptor protein, Skp1. Cul1 associates with one of many F-box proteins through Skp1 to assemble various SCF–Roc1 E3 ligases that each selectively ubiquitinate one or more specific substrates. Here, we show that Cul3, but not other Cullins, binds directly to multiple BTB domains through a conserved amino-terminal domain. In vitro, Cul3 promoted ubiquitination of Caenorhabditis elegans MEI-1, a katanin-like protein whose degradation requires the function of both Cul3 and BTB protein MEL-26. We suggest that in vivo there exists a potentially large number of BCR3 (BTB–Cul3–Roc1) E3 ubiquitin ligases.
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nedd8 modification of cul1 dissociates p120cand1 an inhibitor of cul1 skp1 binding and scf ligases
Molecular Cell, 2002Co-Authors: Manabu Furukawa, Tomohiro Matsumoto, Yue XiongAbstract:Abstract Cullin proteins assemble a large number of RING E3 ubiquitin ligases and regulate various physiological processes. Covalent modification of Cullins by the ubiquitin-like protein NEDD8 activates Cullin ligases through an as yet undefined mechanism. We show here that p120 CAND1 selectively binds to unneddylated CUL1 and is dissociated by CUL1 neddylation. CAND1 formed a ternary complex with CUL1 and ROC1. CAND1 dissociated SKP1 from CUL1 and inhibited SCF ligase activity in vitro. Suppression of CAND1 in vivo increased the level of the CUL1-SKP1 complex. We suggest that by restricting SKP1-CUL1 interaction, CAND1 regulated the assembly of productive SCF ubiquitin ligases, allowing a common CUL1-ROC core to be utilized by a large number of SKP1-F box-substrate subcomplexes.
Raymond J. Deshaies - One of the best experts on this subject based on the ideXlab platform.
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nedd8 links Cullin ring ubiquitin ligase function to the p97 pathway
Nature Structural & Molecular Biology, 2012Co-Authors: Willem Den Besten, Rati Verma, Gary Kleiger, Robert S Oania, Raymond J. DeshaiesAbstract:The AAA+ ATPase p97 and its UBA-UBX cofactors are thought to extract ubiquitinated proteins from membranes or protein complexes as a prelude to their degradation. However, for many cofactors ubiquitinated targets have not yet been identified, leaving their biological function unclear. Previous analysis has linked the p97 pathway to Cullin-RING ubiquitin ligases (CRLs); here we demonstrate that the human p97 cofactor UBXD7 mediates the p97-CRL interaction through its conserved ubiquitin-interacting motif (UIM). UBXD7 and its yeast ortholog, Ubx5, associate only with the active, NEDD8- or Rub1-modified form of Cullins. Disruption of the Ubx5 UIM results in a loss of CRL binding and consequently impedes degradation of a Cul3 substrate. These results uncover an unexpected and conserved role for NEDD8 in linking CRL ubiquitin ligase function to the p97 pathway.
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multimodal activation of the ubiquitin ligase scf by nedd8 conjugation
Molecular Cell, 2008Co-Authors: Anjanabha Saha, Raymond J. DeshaiesAbstract:Conjugation of ubiquitin-like protein Nedd8 to Cullins (neddylation) is essential for the function of Cullin-RING ubiquitin ligases (CRLs). Here, we show that neddylation stimulates CRL activity by multiple mechanisms. For the initiator ubiquitin, the major effect is to bridge the ~50 A° gap between naked substrate and E2 ~ Ub bound to SCF. The gap between the acceptor lysine of ubiquitinated substrate and E2 ~ Ub is much smaller, and, consequentially, the impact of neddylation on transfer of subsequent ubiquitins by Cdc34 arises primarily from improved E2 recruitment and enhanced amide bond formation in the E2 active site. The combined effects of neddylation greatly enhance the probability that a substrate molecule acquires ≥ 4 ubiquitins in a single encounter with a CRL. The surprisingly diverse effects of Nedd8 conjugation underscore the complexity of CRL regulation and suggest that modification of other ubiquitin ligases with ubiquitin or ubiquitin-like proteins may likewise have major functional consequences.
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function and regulation of Cullin ring ubiquitin ligases
Nature Reviews Molecular Cell Biology, 2005Co-Authors: Matthew D Petroski, Raymond J. DeshaiesAbstract:Cullin–RING complexes comprise the largest known class of ubiquitin ligases. Owing to the great diversity of their substrate-receptor subunits, it is possible that there are hundreds of distinct Cullin–RING ubiquitin ligases in eukaryotic cells, which establishes these enzymes as key mediators of post-translational protein regulation. In this review, we focus on the composition, regulation and function of Cullin–RING ligases, and describe how these enzymes can be characterized by a set of general principles.
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human de etiolated 1 regulates c jun by assembling a cul4a ubiquitin ligase
Science, 2004Co-Authors: Raymond J. Deshaies, Ingrid E Wertz, Karen Orourke, Zemin Zhang, David Dornan, David Arnott, Vishva M DixitAbstract:Arabidopsis thaliana De-etiolated-1 (AtDET1) is a highly conserved protein, with orthologs in vertebrate and invertebrate organisms. AtDET1 negatively regulates photomorphogenesis, but its biochemical mechanism and function in other species are unknown. We report that human DET1 (hDET1) promotes ubiquitination and degradation of the proto-oncogenic transcription factor c-Jun by assembling a multisubunit ubiquitin ligase containing DNA Damage Binding Protein-1 (DDB1), Cullin 4A (CUL4A), Regulator of Cullins-1 (ROC1), and constitutively photomorphogenic-1. Ablation of any subunit by RNA interference stabilized c-Jun and increased c-Jun–activated transcription. These findings characterize a c-Jun ubiquitin ligase and define a specific function for hDET1 in mammalian cells.
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the fission yeast cop9 signalosome is involved in Cullin modification by ubiquitin related ned8p
BMC Biochemistry, 2001Co-Authors: Chunshui Zhou, Rory K Geyer, Raymond J. Deshaies, Edward Rhee, Volker Seibert, Svetlana Lyapina, Greg Cope, Dieter A WolfAbstract:Background: The function of the fission yeast Cullins Pcu1p and Pcu4p requires modification by the ubiquitin-related peptide Ned8p. A recent report by Lyapina et al. shows that the COP9/ signalosome (CSN), a multifunctional eight subunit complex, regulates Ned8p modification of Pcu1p. Disruption of caa1/csn1, which encodes subunit 1 of the putative S. pombe CSN, results in accumulation of Pcu1p exclusively in the modified form. However, it remained unclear whether this reflects global control of all Cullins by the entire CSN complex. Results: We demonstrate that multiple CSN subunits control Ned8p modification of Pcu3p, another fission yeast Cullin, which, in complex with the RING domain protein Pip1p, forms a ubiquitin ligase that functions in cellular stress response. Pcu3p is modified by Ned8p on Lys 729 and accumulates exclusively in the neddylated form in cells lacking the CSN subunits 1, 3, 4, and 5. These CSN subunits co-elute with Pcu3p in gel filtration fractions corresponding to ∼ 550 kDa and specifically bind both native and Ned8p-modified Pcu3p in vivo. While CSN does not influence the subcellular localization of Pcu3p, Pcu3p-associated in vitro ubiquitin ligase activity is stimulated in the absence of CSN. Conclusions: Taken together, our data suggest that CSN is a global regulator of Ned8p modification of multiple Cullins and potentially other proteins involved in cellular regulation.
Dieter A Wolf - One of the best experts on this subject based on the ideXlab platform.
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The COP9 signalosome: an assembly and maintenance platform for Cullin ubiquitin ligases?
Nature Cell Biology, 2003Co-Authors: Dieter A Wolf, Chunshui Zhou, Susan WeeAbstract:The COP9 signalosome (CSN) is a highly conserved protein complex implicated in diverse biological functions that involve ubiquitin-mediated proteolysis. Paradoxically, conserved enzymatic activities associated with CSN inhibit Cullin ubiquitin ligase activity in vitro , whereas mutational analysis suggests that CSN promotes Cullin-dependent proteolysis in vivo . This apparent paradox can be resolved in a model that proposes CSN-mediated Cullin inhibition is a prerequisite for the proper assembly and maintenance of active Cullin ubiquitin ligase complexes.
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btb poz domain proteins are putative substrate adaptors for Cullin 3 ubiquitin ligases
Molecular Cell, 2003Co-Authors: Rory K Geyer, Susan Wee, Scott Anderson, John R Yates, Dieter A WolfAbstract:Cullins (CULs) are subunits of a prominent class of RING ubiquitin ligases. Whereas the subunits and substrates of CUL1-associated SCF complexes and CUL2 ubiquitin ligases are well established, they are largely unknown for other Cullin family members. We show here that S. pombe CUL3 (Pcu3p) forms a complex with the RING protein Pip1p and all three BTB/POZ domain proteins encoded in the fission yeast genome. The integrity of the BTB/POZ domain, which shows similarity to the Cullin binding proteins SKP1 and elongin C, is required for this interaction. Whereas Btb1p and Btb2p are stable proteins, Btb3p is ubiquitylated and degraded in a Pcu3p-dependent manner. Btb3p degradation requires its binding to a conserved N-terminal region of Pcu3p that precisely maps to the equivalent SKP1/F box adaptor binding domain of CUL1. We propose that the BTB/POZ domain defines a recognition motif for the assembly of substrate-specific RING/Cullin 3/BTB ubiquitin ligase complexes.
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fission yeast cop9 signalosome suppresses Cullin activity through recruitment of the deubiquitylating enzyme ubp12p
Molecular Cell, 2003Co-Authors: Chunshui Zhou, Susan Wee, Edward Rhee, Michael Naumann, Wolfgang Dubiel, Dieter A WolfAbstract:The COP9/signalosome (CSN) is known to remove the stimulatory NEDD8 modification from Cullins. The activity of the fission yeast Cullins Pcu1p and Pcu3p is dramatically stimulated when retrieved from csn mutants but inhibited by purified CSN. This inhibition is independent of Cullin deneddylation but mediated by the CSN-associated deubiquitylating enzyme Ubp12p, which forms a complex with Pcu3p in a CSN-dependent manner. In ubp12 mutants, as in csn mutants, Pcu3p activity is stimulated. CSN is required for efficient targeting of Ubp12p to the nucleus, where both Cullins reside. Finally, the CSN/Ubp12p pathway maintains the stability of the Pcu1p-associated substrate-specific adaptor protein Pop1p. We propose that CSN/Ubp12p-mediated deubiquitylation creates an environment for the safe de novo assembly of Cullin complexes by counteracting the autocatalytic destruction of adaptor proteins.
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the fission yeast cop9 signalosome is involved in Cullin modification by ubiquitin related ned8p
BMC Biochemistry, 2001Co-Authors: Chunshui Zhou, Rory K Geyer, Raymond J. Deshaies, Edward Rhee, Volker Seibert, Svetlana Lyapina, Greg Cope, Dieter A WolfAbstract:Background: The function of the fission yeast Cullins Pcu1p and Pcu4p requires modification by the ubiquitin-related peptide Ned8p. A recent report by Lyapina et al. shows that the COP9/ signalosome (CSN), a multifunctional eight subunit complex, regulates Ned8p modification of Pcu1p. Disruption of caa1/csn1, which encodes subunit 1 of the putative S. pombe CSN, results in accumulation of Pcu1p exclusively in the modified form. However, it remained unclear whether this reflects global control of all Cullins by the entire CSN complex. Results: We demonstrate that multiple CSN subunits control Ned8p modification of Pcu3p, another fission yeast Cullin, which, in complex with the RING domain protein Pip1p, forms a ubiquitin ligase that functions in cellular stress response. Pcu3p is modified by Ned8p on Lys 729 and accumulates exclusively in the neddylated form in cells lacking the CSN subunits 1, 3, 4, and 5. These CSN subunits co-elute with Pcu3p in gel filtration fractions corresponding to ∼ 550 kDa and specifically bind both native and Ned8p-modified Pcu3p in vivo. While CSN does not influence the subcellular localization of Pcu3p, Pcu3p-associated in vitro ubiquitin ligase activity is stimulated in the absence of CSN. Conclusions: Taken together, our data suggest that CSN is a global regulator of Ned8p modification of multiple Cullins and potentially other proteins involved in cellular regulation.
Yi Sun - One of the best experts on this subject based on the ideXlab platform.
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selective inhibition of Cullin 3 neddylation through covalent targeting dcn1 protects mice from acetaminophen induced liver toxicity
Nature Communications, 2021Co-Authors: Haibin Zhou, Liu Liu, Denzil Bernard, Chao Yie Yang, Krishnapriya Chinnaswamy, Jeanne A Stuckey, Donna Mceachern, Hong Shen, Liangyou Rui, Yi SunAbstract:Cullin-RING E3 ligases (CRLs) regulate the turnover of approximately 20% of mammalian cellular proteins. Neddylation of individual Cullin proteins is essential for the activation of each CRL. We report herein the discovery of DI-1548 and DI-1859 as two potent, selective and covalent DCN1 inhibitors. These inhibitors selectively inhibit neddylation of Cullin 3 in cells at low nanomolar concentrations and are 2-3 orders of magnitude more potent than our previously reported reversible DCN1 inhibitor. Mass spectrometric analysis and co-crystal structures reveal that these compounds employ a unique mechanism of covalent bond formation with DCN1. DI-1859 induces a robust increase of NRF2 protein, a CRL3 substrate, in mouse liver and effectively protects mice from acetaminophen-induced liver damage. Taken together, this study demonstrates the therapeutic potential of selective inhibition of Cullin neddylation.
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targeting protein neddylation to inactivate Cullin ring ligases by gossypol a lucky hit or a new start
Drug Design Development and Therapy, 2021Co-Authors: Yi SunAbstract:Abstract Cullin-RING E3 ligases (CRLs) are the largest family of E3 ubiquitin ligases, responsible for about 20% of the protein degradation by the ubiquitin-proteasome system (UPS). Given their vital roles in multiple cellular processes, and over-activation in many human cancers, CRLs are validated as promising targets for anti-cancer therapies. Activation of CRLs requires Cullin neddylation, a process catalysed by three neddylation enzymes. Recently, our group established an AlphaScreen-based in vitro Cullin neddylation assay and employed it for high-throughput screening to search for small-molecule inhibitors targeting Cullin neddylation. During our pilot screen, gossypol, a natural product extracted from cottonseeds, was identified as one of the most potent neddylation inhibitors of Cullin-1 and Cullin-5. We further demonstrated that gossypol blocks Cullin neddylation by binding to Cullin-1/-5 to inactivate CRL1/5 ligase activity, leading to accumulation of MCL-1 and NOXA, the substrates of CRL1 and CRL5, respectively. The combination of gossypol and an MCL-1 inhibitor synergistically enhanced the anti-proliferative effect in multiple human cancer cell lines. Our study unveiled a rational combination of two previously known inhibitors of the Bcl-2 family for enhanced anti-cancer efficacy and identified a novel activity of gossypol as an inhibitor of CRL1 and CRL5 E3s, thus providing a new possibility in the development of novel CRL inhibitors for anti-cancer therapy.
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Cullin ring ligase 5 functional characterization and its role in human cancers
Seminars in Cancer Biology, 2020Co-Authors: Yongchao Zhao, Xiufang Xiong, Yi SunAbstract:Cullin-RING ligase 5 (CRL5) is a multi-protein complex and consists of a scaffold protien Cullin 5, a RING protein RBX2 (also known as ROC2 or SAG), adaptor proteins Elongin B/C, and a substrate receptor protein SOCS. Through targeting a variety of substrates for proteasomal degradation or modulating various protein-protein interactions, CRL5 is involved in regulation of many biological processes, such as cytokine signal transduction, inflammation, viral infection, and oncogenesis. As many substrates of CRL5 are well-known oncoproteins or tumor suppressors, abnormal regulation of CRL5 is commonly found in human cancers. In this review, we first briefly introduce each of CRL5 components, and then discuss the biological processes regulated by four members of SOCS-box-containing substrate receptor family through substrate degradation. We next describe how CRL5 is hijacked by a variety of viral proteins to degrade host anti-viral proteins, which facilitates virus infection. We further discuss the regulation of CUL5 and its various roles in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose novel insights for future perspectives on the validation of Cullin5 and other CRL5 components as potential targets, and possible targeting strategies to discover CRL5 inhibitors for anti-cancer and anti-virus therapies.
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discovery of candesartan cilexetic as a novel neddylation inhibitor for suppressing tumor growth
European Journal of Medicinal Chemistry, 2020Co-Authors: Xin Chen, Yi Sun, Wenjuan Zhang, Junqian Zhang, Xi Yang, Fei Mao, Jing Huang, Lijun JiaAbstract:Abstract Protein neddylation is a posttranslational modification of conjugating the neuronal precursor cell-expressed developmentally down-regulated protein 8 (Nedd8) to substrates. Our previous work revealed that neddylation pathway is overactivated in various human lung cancers and correlates with the disease progression, whereas pharmacologically targeting this pathway has emerged as an attractive therapeutic strategy. As a follow-up research, 1331 approved drugs were investigated the inhibitory activities of Cullin1 neddylation for screening the hit compounds via an improved enzyme-based assay. An antihypertensive agent, candesartan cilexetic (CDC), was identified as a novel neddylation inhibitor that ATP-competitively suppressing Nedd8-activating enzyme (NAE, E1) in mechanism, which inhibited the Cullins neddylation superior than two representative non-covalent NAE inhibitors, M22 and mitoxantrone. Following with the findings such as apoptotic induction and tumor growth suppression in human lung cancer A549 in vitro and in vivo, CDC represents a potential anticancer lead compound with promising neddylation inhibitory activity.
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targeting neddylation pathways to inactivate Cullin ring ligases for anticancer therapy
Antioxidants & Redox Signaling, 2014Co-Authors: Yongchao Zhao, Meredith A Morgan, Yi SunAbstract:Abstract Significance: Protein neddylation is catalyzed by an E1 NEDD8-activating enzyme (NAE), an E2 NEDD8-conjugating enzyme, and an E3 NEDD8 ligase. Known physiological substrates of neddylation are Cullin family members. Cullin neddylation leads to activation of Cullin-RING ligases (CRLs), the largest family of E3 ubiquitin ligases responsible for ubiquitylation and degradation of many key signaling/regulatory proteins. Thus, through modulating CRLs, neddylation regulates many biological processes, including cell cycle progression, signal transduction, and tumorigenesis. Given that NEDD8 is overexpressed and CRLs are abnormally activated in many human cancers, targeting protein neddylation, in general, and Cullin neddylation, in particular, appears to be an attractive anticancer approach. Recent Advances: MLN4924, a small molecule inhibitor of NAE, was discovered that inactivates CRLs and causes accumulation of CRL substrates to suppress tumor cell growth both in vitro and in vivo. Promising preclinic...