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Asano W, Hantani R, Uhara T, Debaene F, Nomura A, Yamaguchi K, Adachi T, Otake K, Harada K, Hantani Y. Screening approaches for the identification of Nrf2-Keap1 protein-protein interaction inhibitors targeting hot spot residues. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2024; 29:100125. [PMID: 37935317 DOI: 10.1016/j.slasd.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/29/2023] [Accepted: 11/03/2023] [Indexed: 11/09/2023]
Abstract
Protein-protein interactions (PPIs) play a crucial role in most biological processes and are important targets in the development of therapeutic agents. However, small molecule drug discovery that targets PPIs remains very challenging. Targeting hot spot residues is considered the best option for inhibiting such interactions, but there are few examples of how knowledge of hot spots can be used in high throughput screening to find hit compounds. A substrate adaptor protein for a ubiquitin ligase complex, Kelch-like ECH-associated protein 1 (Keap1), negatively modulates the expression of genes involved in cellular protection against oxidative stress. Here, we focused on three arginine hot spot residues in the Keap1 substrate binding pocket (Arg380, Arg415, and Arg483), and screened the carboxylic acid library owned by Japan Tobacco Inc. for compounds that interact with the arginine residues in differential scanning fluorescence assays. Furthermore, we identified several small molecule compounds that specifically bind to the Keap1 Kelch domain hot spots by comparing binding to alanine mutant proteins (R380A, R415A, and R483A) with binding to the wild-type protein using surface plasmon resonance (SPR) screening. These compounds inhibited the protein-protein interaction between the Keap1 Kelch domain and the nuclear factor erythroid 2-related factor 2 (Nrf2) peptide, and the ubiquitination of Nrf2 catalyzed by the Cul3/RINGBox 1 E3 ligase. In addition, the binding mode of one compound (Compound 4) was determined by X-ray crystallography after validation of binding by isothermal titration calorimetry, native mass spectrometry, and nuclear magnetic resonance. Compound 4 had favorable thermodynamic properties, and noncovalently bound to Keap1 with a stoichiometry of 1:1. Our results suggest that Compound 4 could potentially be developed into effective therapeutic or preventive agents for a variety of diseases and conditions such as oxidative stress response, inflammation, and carcinogenesis. We believe that the use of a set of complementary biophysical techniques including the SPR assay with single alanine mutant of hot spots provides opportunities to identify hit compounds for developing inhibitors of PPIs.
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Affiliation(s)
- Wataru Asano
- Biological/Pharmacological Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Rie Hantani
- Biological/Pharmacological Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Toru Uhara
- Biological/Pharmacological Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - François Debaene
- Biophysics Dpt/ MS Platform, NovAliX, 16 rue d'Ankara, Strasbourg 67000, France
| | - Akihiro Nomura
- Chemical Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Keishi Yamaguchi
- Chemical Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Tsuyoshi Adachi
- Chemical Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Kazuki Otake
- Chemical Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Kazuhito Harada
- Chemical Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan
| | - Yoshiji Hantani
- Biological/Pharmacological Research Laboratories, Central Pharmaceutical Research Institute, Japan Tobacco Inc., 1-1, Murasaki-cho, Takatsuki, Osaka 569-1125, Japan.
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Suresh K, Mattern M, Goldberg MS, Butt TR. The Ubiquitin Proteasome System as a Therapeutic Area in Parkinson's Disease. Neuromolecular Med 2023; 25:313-329. [PMID: 36739586 DOI: 10.1007/s12017-023-08738-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/28/2023] [Indexed: 02/06/2023]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder. There are no available therapeutics that slow or halt the progressive loss of dopamine-producing neurons, which underlies the primary clinical symptoms. Currently approved PD drugs can provide symptomatic relief by increasing brain dopamine content or activity; however, the alleviation is temporary, and the effectiveness diminishes with the inevitable progression of neurodegeneration. Discovery and development of disease-modifying neuroprotective therapies has been hampered by insufficient understanding of the root cause of PD-related neurodegeneration. The etiology of PD involves a combination of genetic and environmental factors. Although a single cause has yet to emerge, genetic, cell biological and neuropathological evidence implicates mitochondrial dysfunction and protein aggregation. Postmortem PD brains show pathognomonic Lewy body intraneuronal inclusions composed of aggregated α-synuclein, indicative of failure to degrade misfolded protein. Mutations in the genes that code for α-synuclein, as well as the E3 ubiquitin ligase Parkin, cause rare inherited forms of PD. While many ubiquitin ligases label proteins with ubiquitin chains to mark proteins for degradation by the proteasome, Parkin has been shown to mark dysfunctional mitochondria for degradation by mitophagy. The ubiquitin proteasome system participates in several aspects of the cell's response to mitochondrial damage, affording numerous therapeutic opportunities to augment mitophagy and potentially stop PD progression. This review examines the role and therapeutic potential of such UPS modulators, exemplified by both ubiquitinating and deubiquitinating enzymes.
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Affiliation(s)
- Kumar Suresh
- Progenra Inc., 271A Great Valley Parkway, Malvern, PA, 19355, USA.
| | - Michael Mattern
- Progenra Inc., 271A Great Valley Parkway, Malvern, PA, 19355, USA
| | - Matthew S Goldberg
- Department of Neurology, The University of Alabama at Birmingham, Birmingham, AL, USA
- Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tauseef R Butt
- Progenra Inc., 271A Great Valley Parkway, Malvern, PA, 19355, USA
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3
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Trempe JF, Gehring K. Structural mechanisms of mitochondrial quality control mediated by PINK1 and parkin. J Mol Biol 2023:168090. [PMID: 37054910 DOI: 10.1016/j.jmb.2023.168090] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/31/2023] [Accepted: 04/05/2023] [Indexed: 04/15/2023]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease and represents a looming public health crisis as the global population ages. While the etiology of the more common, idiopathic form of the disease remains unknown, the last ten years have seen a breakthrough in our understanding of the genetic forms related to two proteins that regulate a quality control system for the removal of damaged or non-functional mitochondria. Here, we review the structure of these proteins, PINK1, a protein kinase, and parkin, a ubiquitin ligase with an emphasis on the molecular mechanisms responsible for their recognition of dysfunctional mitochondria and control of the subsequent ubiquitination cascade. Recent atomic structures have revealed the basis of PINK1 substrate specificity and the conformational changes responsible for activation of PINK1 and parkin catalytic activity. Progress in understanding the molecular basis of mitochondrial quality control promises to open new avenues for therapeutic interventions in PD.
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Affiliation(s)
- Jean-François Trempe
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada; Centre de Recherche en Biologie Structurale
| | - Kalle Gehring
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada; Centre de Recherche en Biologie Structurale
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4
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Michaelides IN, Collie GW. E3 Ligases Meet Their Match: Fragment-Based Approaches to Discover New E3 Ligands and to Unravel E3 Biology. J Med Chem 2023; 66:3173-3194. [PMID: 36821822 PMCID: PMC10009759 DOI: 10.1021/acs.jmedchem.2c01882] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Indexed: 02/25/2023]
Abstract
Ubiquitination is a key post-translational modification of proteins, affecting the regulation of multiple cellular processes. Cells are equipped with over 600 ubiquitin orchestrators, called E3 ubiquitin ligases, responsible for directing the covalent attachment of ubiquitin to substrate proteins. Due to their regulatory role in cells, significant efforts have been made to discover ligands for E3 ligases. The recent emergence of the proteolysis targeting chimera (PROTAC) and molecular glue degrader (MGD) modalities has further increased interest in E3 ligases as drug targets. This perspective focuses on how fragment based lead discovery (FBLD) methods have been used to discover new ligands for this important target class. In some cases these efforts have led to clinical candidates; in others, they have provided tools for deepening our understanding of E3 ligase biology. Recently, FBLD-derived ligands have inspired the design of PROTACs that are able to artificially modulate protein levels in cells.
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Affiliation(s)
- Iacovos N. Michaelides
- Discovery Sciences, BioPharmaceuticals
R&D, AstraZeneca, Cambridge, CB4 0WG, United
Kingdom
| | - Gavin W. Collie
- Discovery Sciences, BioPharmaceuticals
R&D, AstraZeneca, Cambridge, CB4 0WG, United
Kingdom
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5
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A Novel Method for Identifying Parkin Binding Agents in Complex Preparations of Herbal Medicines. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:3260243. [PMID: 35087614 PMCID: PMC8789414 DOI: 10.1155/2022/3260243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/11/2021] [Accepted: 12/04/2021] [Indexed: 11/24/2022]
Abstract
Parkin is a crucial E3 ubiquitin ligase for initiating mitophagy through the PINK1/Parkin pathway. Regulating the expression and activity of parkin can remedy mitophagy and human disease. We developed an efficient method to isolate natural parkin ligands from herbal medicines by combining centrifugal ultrafiltration and liquid chromatography/mass spectrometry. The heterologous expression technology identified functionally active and pure parkin proteins. After evaluating the reliability of the method using DL-selenomethionine and DL-dithiothreitol as positive controls, this method was successfully applied to capture parkin ligands from Polygoni Cuspidati Rhizoma et Radix and Sophorae Flavescentis Radix. LC/MS identified seven novel parkin-targeting compounds, namely, 7,4′-dihydroxy-5-methoxy-8-(γ, γ-dimethylallyl)-flavanone, kushenol I, kurarinone, sophoraflavanone G, torachrysone-8-O-glucoside, apigenin, and emodin, supported by the molecular docking analysis. Five of the seven novel compounds (kushenol I, kurarinone, sophoraflavanone G, apigenin, and emodin) can activate parkin in in vitro autoubiquitination assays. Meanwhile, kushenol I and kurarinone had antisteatosis activity in fat emulsion-damaged human hepatocytes. These results confirmed the effectiveness of the method for identifying parkin ligands from complex preparations, useful to advance drug discovery from medicinal herbs.
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6
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De Cesare V, Johnson C, Barlow V, Hastie J, Knebel A, Trost M. The MALDI-TOF E2/E3 Ligase Assay as Universal Tool for Drug Discovery in the Ubiquitin Pathway. Cell Chem Biol 2018; 25:1117-1127.e4. [PMID: 30017913 PMCID: PMC6162346 DOI: 10.1016/j.chembiol.2018.06.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/14/2018] [Accepted: 06/08/2018] [Indexed: 12/18/2022]
Abstract
Due to their role in many diseases, enzymes of the ubiquitin system have recently become interesting drug targets. Despite efforts, primary screenings of compound libraries targeting E2 enzymes and E3 ligases have been strongly limited by the lack of robust and fast high-throughput assays. Here we report a label-free high-throughput screening assay for ubiquitin E2 conjugating enzymes and E3 ligases based on MALDI-TOF mass spectrometry. The MALDI-TOF E2/E3 assay allows testing E2 enzymes and E3 ligases for their ubiquitin transfer activity, identifying E2/E3 active pairs, inhibitor potency and specificity and screening compound libraries in vitro without chemical or fluorescent probes. We demonstrate that the MALDI-TOF E2/E3 assay is a universal tool for drug discovery screening in the ubiquitin pathway as it is suitable for working with all E3 ligase families and requires a reduced amount of reagents, compared with standard biochemical assays. We have developed a high-throughput MALDI-TOF assay for E2/E3 enzymes It allows screening compound libraries without chemical or fluorescent probes We tested the screen on three disease-relevant E3 ligases: MDM2, ITCH, and HOIP We performed a proof-of-concept high-throughput screen against 1,430 compounds
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Affiliation(s)
- Virginia De Cesare
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK.
| | - Clare Johnson
- MRC Protein Phosphorylation and Ubiquitylation Unit Reagents and Services, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK
| | - Victoria Barlow
- MRC Protein Phosphorylation and Ubiquitylation Unit Reagents and Services, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK
| | - James Hastie
- MRC Protein Phosphorylation and Ubiquitylation Unit Reagents and Services, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK
| | - Axel Knebel
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK
| | - Matthias Trost
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dow St, Dundee DD1 5EH, Scotland, UK; Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 1HH, UK.
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7
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Park S, Foote PK, Krist DT, Rice SE, Statsyuk AV. UbMES and UbFluor: Novel probes for ring-between-ring (RBR) E3 ubiquitin ligase PARKIN. J Biol Chem 2017; 292:16539-16553. [PMID: 28710279 DOI: 10.1074/jbc.m116.773200] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 07/03/2017] [Indexed: 12/30/2022] Open
Abstract
Ring-between-ring (RBR) E3 ligases have been implicated in autoimmune disorders and neurodegenerative diseases. The functions of many RBR E3s are poorly defined, and their regulation is complex, involving post-translational modifications and allosteric regulation with other protein partners. The functional complexity of RBRs, coupled with the complexity of the native ubiquitination reaction that requires ATP and E1 and E2 enzymes, makes it difficult to study these ligases for basic research and therapeutic purposes. To address this challenge, we developed novel chemical probes, ubiquitin C-terminal fluorescein thioesters UbMES and UbFluor, to qualitatively and quantitatively assess the activity of the RBR E3 ligase PARKIN in a simple experimental setup and in real time using fluorescence polarization. First, we confirmed that PARKIN does not require an E2 enzyme for substrate ubiquitination, lysine selection, and polyubiquitin chain formation. Second, we confirmed that UbFluor quantitatively detects naturally occurring activation states of PARKIN caused by Ser65 phosphorylation (pPARKIN) and phosphorylated ubiquitin (pUb). Third, we showed that both pUb and the ubiquitin-accepting substrate contribute to maximal pPARKIN ubiquitin conjugation turnover. pUb enhances the transthiolation step, whereas the substrate clears the pPARKIN∼Ub thioester intermediate. Finally, we established that UbFluor can quantify activation or inhibition of PARKIN by structural mutations. These results demonstrate the feasibility of using UbFluor for quantitative studies of the biochemistry of RBR E3s and for high-throughput screening of small-molecule activators or inhibitors of PARKIN and other RBR E3 ligases.
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Affiliation(s)
- Sungjin Park
- From the Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois 60611
| | - Peter K Foote
- the Chemistry of Life Processes Institute, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, and
| | - David T Krist
- the Chemistry of Life Processes Institute, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, and
| | - Sarah E Rice
- From the Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois 60611
| | - Alexander V Statsyuk
- the Chemistry of Life Processes Institute, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, and .,the Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas 77204-5037
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8
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Label-enhanced surface plasmon resonance applied to label-free interaction analysis of small molecules and fragments. Anal Biochem 2016; 510:79-87. [DOI: 10.1016/j.ab.2016.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/24/2016] [Accepted: 06/06/2016] [Indexed: 12/30/2022]
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9
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Seirafi M, Kozlov G, Gehring K. Parkin structure and function. FEBS J 2015; 282:2076-88. [PMID: 25712550 PMCID: PMC4672691 DOI: 10.1111/febs.13249] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 01/05/2015] [Accepted: 02/24/2015] [Indexed: 02/06/2023]
Abstract
Mutations in the parkin or PINK1 genes are the leading cause of the autosomal recessive form of Parkinson’s disease. The gene products, the E3 ubiquitin ligase parkin and the serine/threonine kinase PINK1, are neuroprotective proteins, which act together in a mitochondrial quality control pathway. Here, we review the structure of parkin and mechanisms of its autoinhibition and function as a ubiquitin ligase. We present a model for the recruitment and activation of parkin as a key regulatory step in the clearance of depolarized or damaged mitochondria by autophagy (mitophagy). We conclude with a brief overview of other functions of parkin and considerations for drug discovery in the mitochondrial quality control pathway.
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Affiliation(s)
- Marjan Seirafi
- Department of Biochemistry and the Groupe de Recherche axé sur la Structure des Protéines, McGill University, Montréal, Québec, Canada
| | - Guennadi Kozlov
- Department of Biochemistry and the Groupe de Recherche axé sur la Structure des Protéines, McGill University, Montréal, Québec, Canada
| | - Kalle Gehring
- Department of Biochemistry and the Groupe de Recherche axé sur la Structure des Protéines, McGill University, Montréal, Québec, Canada
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10
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Grishin AM, Condos TEC, Barber KR, Campbell-Valois FX, Parsot C, Shaw GS, Cygler M. Structural basis for the inhibition of host protein ubiquitination by Shigella effector kinase OspG. Structure 2014; 22:878-88. [PMID: 24856362 DOI: 10.1016/j.str.2014.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/19/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022]
Abstract
Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the "open" conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Tara E C Condos
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Kathryn R Barber
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | | | - Claude Parsot
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada.
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11
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Abstract
The RBR (RING-BetweenRING-RING) or TRIAD [two RING fingers and a DRIL (double RING finger linked)] E3 ubiquitin ligases comprise a group of 12 complex multidomain enzymes. This unique family of E3 ligases includes parkin, whose dysfunction is linked to the pathogenesis of early-onset Parkinson's disease, and HOIP (HOIL-1-interacting protein) and HOIL-1 (haem-oxidized IRP2 ubiquitin ligase 1), members of the LUBAC (linear ubiquitin chain assembly complex). The RBR E3 ligases share common features with both the larger RING and HECT (homologous with E6-associated protein C-terminus) E3 ligase families, directly catalysing ubiquitin transfer from an intrinsic catalytic cysteine housed in the C-terminal domain, as well as recruiting thioester-bound E2 enzymes via a RING domain. Recent three-dimensional structures and biochemical findings of the RBRs have revealed novel protein domain folds not previously envisioned and some surprising modes of regulation that have raised many questions. This has required renaming two of the domains in the RBR E3 ligases to more accurately reflect their structures and functions: the C-terminal Rcat (required-for-catalysis) domain, essential for catalytic activity, and a central BRcat (benign-catalytic) domain that adopts the same fold as the Rcat, but lacks a catalytic cysteine residue and ubiquitination activity. The present review discusses how three-dimensional structures of RBR (RING1-BRcat-Rcat) E3 ligases have provided new insights into our understanding of the biochemical mechanisms of these important enzymes in ubiquitin biology.
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12
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Nicholson B, Kumar S, Agarwal S, Eddins MJ, Marblestone JG, Wu J, Kodrasov MP, LaRocque JP, Sterner DE, Mattern MR. Discovery of Therapeutic Deubiquitylase Effector Molecules. ACTA ACUST UNITED AC 2014; 19:989-99. [DOI: 10.1177/1087057114527312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/14/2014] [Indexed: 12/28/2022]
Abstract
The approval of proteasome inhibitors bortezomib and carfilzomib and the E3 ligase antagonist thalidomide and its analogs, lenalidomide and pomalidomide, validates the ubiquitin–proteasome pathway as a source of novel drugs for treating cancer and, potentially, a variety of devastating illnesses, including inflammation, cardiovascular disease, and neurodegenerative disease. All elements of this critical regulatory pathway—the proteasome itself, E3 ligases (which conjugate ubiquitin to target proteins), and deubiquitylating enzymes (which deconjugate ubiquitin, reversing ligase action)—are potential therapeutic targets, and all have been worked on extensively during the past decade. No deubiquitylase inhibitors or activators have yet progressed to clinical trial, however, despite compelling target validation and several years of high-throughput screening and preclinical development of hits by numerous pharmaceutical companies, biotechnology organizations, and academic groups. The appropriateness of deubiquitylases as therapeutic targets in many disease areas is reviewed, followed by evidence that selective inhibitors of these cysteine proteases can be discovered. Because the lack of progress in drug-discovery efforts with deubiquitylases suggests a need for improved discovery methodologies, currently available platforms and strategies are analyzed, and improved or completely novel, unrelated approaches are considered in terms of their likelihood of producing clinically viable effectors of deubiquitylases.
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Affiliation(s)
| | | | | | | | | | - J. Wu
- Progenra, Inc., Malvern, PA, USA
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