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Abstract
Phosphatases and kinases maintain an equilibrium of dephosphorylated and phosphorylated proteins, respectively, that are required for critical cellular functions. Imbalance in this equilibrium or irregularity in their function causes unfavorable cellular effects that have been implicated in the development of numerous diseases. Protein tyrosine phosphatases (PTPs) catalyze the dephosphorylation of protein substrates on tyrosine residues, and their involvement in cell signaling and diseases such as cancer and inflammatory and metabolic diseases has made them attractive therapeutic targets. However, PTPs have proved challenging in therapeutics development, garnering them the unfavorable reputation of being undruggable. Nonetheless, great strides have been made toward the inhibition of PTPs over the past decade. Here, we discuss the advancement in small-molecule inhibition for the PTP subfamily known as the mitogen-activated protein kinase (MAPK) phosphatases (MKPs). We review strategies and inhibitor discovery tools that have proven successful for small-molecule inhibition of the MKPs and discuss what the future of MKP inhibition potentially might yield.
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Affiliation(s)
- Shanelle R Shillingford
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Anton M Bennett
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut, USA;
- Yale Center for Molecular and Systems Metabolism, Yale University School of Medicine, New Haven, Connecticut, USA
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A novel site on dual-specificity phosphatase MKP7/DUSP16 is required for catalysis and MAPK binding. J Biol Chem 2022; 298:102617. [PMID: 36272649 PMCID: PMC9676401 DOI: 10.1016/j.jbc.2022.102617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 10/06/2022] [Accepted: 10/11/2022] [Indexed: 11/18/2022] Open
Abstract
The dual-specificity phosphatases responsible for the inactivation of the mitogen-activated protein kinases (MAPKs) are designated as the MAPK phosphatases (MKPs). We demonstrated previously that MKP5 is regulated through a novel allosteric site suggesting additional regulatory mechanisms of catalysis exist amongst the MKPs. Here, we sought to determine whether the equivalent site within the phosphatase domain of a highly similar MKP family member, MKP7, is also important for phosphatase function. We found that mutation of tyrosine 271 (Y271) in MKP7, which represents the comparable Y435 within the MKP5 allosteric pocket, inhibited MKP7 catalytic activity. Consistent with this, when MKP7 Y271 mutants were overexpressed in cells, the substrates of MKP7, p38 MAPK or JNK, failed to undergo dephosphorylation. The binding efficiency of MKP7 to p38 MAPK and JNK1/2 was also reduced when MKP7 Y271 is mutated. Consistent with reduced MAPK binding, we observed a greater accumulation of nuclear p38 MAPK and JNK when the MKP7 Y271 mutants are expressed in cells as compared with WT MKP7, which sequesters p38 MAPK/JNK in the cytoplasm. Therefore, we propose that Y271 is critical for effective MAPK dephosphorylation through a mechanism whereby binding to this residue precedes engagement of the catalytic site and upon overexpression, MKP7 allosteric site mutants potentiate MAPK signaling. These results provide insight into the regulatory mechanisms of MKP7 catalysis and interactions with the MAPKs. Furthermore, these data support the generality of the MKP allosteric site and provide a basis for small molecule targeting of MKP7.
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Slater O, Kontoyianni M. The compromise of virtual screening and its impact on drug discovery. Expert Opin Drug Discov 2019; 14:619-637. [PMID: 31025886 DOI: 10.1080/17460441.2019.1604677] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Introduction: Docking and structure-based virtual screening (VS) have been standard approaches in structure-based design for over two decades. However, our understanding of the limitations, potential, and strength of these techniques has enhanced, raising expectations. Areas covered: Based on a survey of reports in the past five years, we assess whether VS: (1) predicts binding poses in agreement with crystallographic data (when available); (2) is a superior screening tool, as often claimed; (3) is successful in identifying chemical scaffolds that can be starting points for subsequent lead optimization cycles. Data shows that knowledge of the target and its chemotypes in postprocessing lead to viable hits in early drug discovery endeavors. Expert opinion: VS is capable of accurate placements in the pocket for the most part, but does not consistently score screening collections accurately. What matters is capitalization on available resources to get closer to a viable lead or optimizable series. Integration of approaches, subjective hit selection guided by knowledge of the receptor or endogenous ligand, libraries driven by experimental guides, validation studies to identify the best docking/scoring that reproduces experimental findings, constraints regarding receptor-ligand interactions, thoroughly designed methodologies, and predefined cutoff scoring criteria strengthen VS's position in pharmaceutical research.
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Affiliation(s)
- Olivia Slater
- a Department of Pharmaceutical Sciences , Southern Illinois University Edwardsville , Edwardsville , IL , USA
| | - Maria Kontoyianni
- a Department of Pharmaceutical Sciences , Southern Illinois University Edwardsville , Edwardsville , IL , USA
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Small molecule targeting of PTPs in cancer. Int J Biochem Cell Biol 2017; 96:171-181. [PMID: 28943273 DOI: 10.1016/j.biocel.2017.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 01/28/2023]
Abstract
Protein tyrosine phosphatases (PTPs) undeniably have a central role in the development and progression of human cancers. Historically, however, PTPs have not been viewed as privileged drug targets, and progress on identifying potent, selective, and cell-active small molecule PTP inhibitors has suffered accordingly. This situation is rapidly changing, however, due to biochemical advances in the study of PTPs and recent small molecule screening campaigns, which have identified potent and mechanistically diverse lead structures. These compounds are facilitating the exploration of the fundamental cellular processes controlled by PTPs in cancers, and could form the inflection point for new therapeutic paradigms for the treatment of a range of cancers. Herein, we review recent advances in the discovery and biological annotation of cancer-relevant small molecule PTP inhibitors.
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Bhore N, Wang BJ, Chen YW, Liao YF. Critical Roles of Dual-Specificity Phosphatases in Neuronal Proteostasis and Neurological Diseases. Int J Mol Sci 2017; 18:ijms18091963. [PMID: 28902166 PMCID: PMC5618612 DOI: 10.3390/ijms18091963] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 12/31/2022] Open
Abstract
Protein homeostasis or proteostasis is a fundamental cellular property that encompasses the dynamic balancing of processes in the proteostasis network (PN). Such processes include protein synthesis, folding, and degradation in both non-stressed and stressful conditions. The role of the PN in neurodegenerative disease is well-documented, where it is known to respond to changes in protein folding states or toxic gain-of-function protein aggregation. Dual-specificity phosphatases have recently emerged as important participants in maintaining balance within the PN, acting through modulation of cellular signaling pathways that are involved in neurodegeneration. In this review, we will summarize recent findings describing the roles of dual-specificity phosphatases in neurodegeneration and offer perspectives on future therapeutic directions.
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Affiliation(s)
- Noopur Bhore
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Bo-Jeng Wang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Yun-Wen Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
| | - Yung-Feng Liao
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang-Ming University and Academia Sinica, Taipei 11529, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan.
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Lazo JS, McQueeney KE, Sharlow ER. New Approaches to Difficult Drug Targets: The Phosphatase Story. SLAS DISCOVERY 2017; 22:1071-1083. [DOI: 10.1177/2472555217721142] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The drug discovery landscape is littered with promising therapeutic targets that have been abandoned because of insufficient validation, historical screening failures, and inferior chemotypes. Molecular targets once labeled as “undruggable” or “intractable” are now being more carefully interrogated, and while they remain challenging, many target classes are appearing more approachable. Protein tyrosine phosphatases represent an excellent example of a category of molecular targets that have emerged as druggable, with several small molecules and antibodies recently becoming available for further development. In this review, we examine some of the diseases that are associated with protein tyrosine phosphatase dysfunction and use some prototype contemporary strategies to illustrate approaches that are being used to identify small molecules targeting this enzyme class.
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Affiliation(s)
- John S. Lazo
- Department of Pharmacology, Fiske Drug Discovery Laboratory, University of Virginia, Charlottesville, VA, USA
| | - Kelley E. McQueeney
- Department of Pharmacology, Fiske Drug Discovery Laboratory, University of Virginia, Charlottesville, VA, USA
| | - Elizabeth R. Sharlow
- Department of Pharmacology, Fiske Drug Discovery Laboratory, University of Virginia, Charlottesville, VA, USA
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Kim D, Park JY, Kim JH. Docking-based In SilicoScreening for Identification of Micromolar Inhibitors of Tropomyosin-related Kinase A from Natural Origin. B KOREAN CHEM SOC 2017. [DOI: 10.1002/bkcs.11064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Daehyun Kim
- Department of Chemistry; Chung-Ang University; Seoul 06974 Korea
| | - Jung Youl Park
- Industry-Academic Cooperation Foundation; Hanbat National University; Daejeon 34158 Korea
| | - Ji-Hyun Kim
- National CRI-Center for Chemical Dynamics in Living Cells; Chung-Ang University; Seoul 06974 Korea
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Park H, Lee HS, Kim SJ. Virtual Screening with Docking Simulations and Biochemical Evaluation of VHY Phosphatase Inhibitors. Chem Pharm Bull (Tokyo) 2016; 63:807-11. [PMID: 26423037 DOI: 10.1248/cpb.c15-00431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although VH1-related member Y (VHY) phosphatase is responsible for the pathogenesis of neuroinflammatory diseases, no small-molecule inhibitor of VHY has been reported so far. Here we first report eight VHY inhibitors identified from molecular docking-based virtual screening and subsequent enzyme inhibition assays. These inhibitors exhibit good biochemical potencies against VHY, with associated IC50 values ranging from 1 to 9 µM. Because all these inhibitors were also screened in silico for having desirable physicochemical properties as a drug candidate, they deserve further investigation by structure-activity relationship studies to develop new medicines for the treatment of neuroinflammatory diseases. The structural features of VHY-inhibitor interactions relevant to the micromolar-level inhibitory activity are addressed in detail.
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Affiliation(s)
- Hwangseo Park
- Department of Bioscience and Biotechnology, Sejong University
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Park H, Lee S, Hong S. Discovery of Dual Inhibitors for Wild Type and D816V Mutant of c-KIT Kinase through Virtual and Biochemical Screening of Natural Products. JOURNAL OF NATURAL PRODUCTS 2016; 79:293-299. [PMID: 26807861 DOI: 10.1021/acs.jnatprod.5b00851] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Although stem cell factor receptor (c-KIT) kinase is responsible for various malignant human cancers, the presence of constitutively active gain-of-function mutants has made it difficult to discover new anticancer agents using c-KIT as the target protein. To identify the common inhibitors of wild-type c-KIT and the most abundant gain-of-function mutant (D816V), the virtual screening of natural products was performed for the two target proteins in parallel with the scoring function improved by implementing a sophisticated solvation free energy term. As a result, four common inhibitors of natural origin are found with biochemical potencies ranging from low micromolar to submicromolar levels. The results of extensive docking simulations show that although the natural-product inhibitors establish weaker hydrophobic interactions with the D816V mutant than with the wild type, they exhibit a little higher inhibitory activity for the former than the latter by strengthening the hydrogen-bond interactions to a sufficient extent. Of the four natural-product inhibitors, (Z)-6-hydroxy-2-(4-methoxybenzylidene)benzofuran-3(2H)-one (3) is anticipated to serve as a new molecular core for the structure-activity relationship studies to optimize the biochemical potencies because it exhibits good inhibitory activity against both the wild type and D816V mutant despite its low molecular weight (268.3 amu).
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Affiliation(s)
- Hwangseo Park
- Department of Bioscience and Biotechnology & Institute of Anticancer Medicine Development, Sejong University , 209 Neungdong-ro, Kwangjin-gu, Seoul 143-747, Korea
| | - Soyoung Lee
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) & Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea
| | - Sungwoo Hong
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS) & Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea
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Spyrakis F, Cavasotto CN. Open challenges in structure-based virtual screening: Receptor modeling, target flexibility consideration and active site water molecules description. Arch Biochem Biophys 2015; 583:105-19. [DOI: 10.1016/j.abb.2015.08.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 08/03/2015] [Accepted: 08/03/2015] [Indexed: 01/05/2023]
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