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Clausse V, Tao D, Debnath S, Fang Y, Tagad HD, Wang Y, Sun H, LeClair CA, Mazur SJ, Lane K, Shi ZD, Vasalatiy O, Eells R, Baker LK, Henderson MJ, Webb MR, Shen M, Hall MD, Appella E, Appella DH, Coussens NP. Physiologically relevant orthogonal assays for the discovery of small-molecule modulators of WIP1 phosphatase in high-throughput screens. J Biol Chem 2019; 294:17654-17668. [PMID: 31481464 PMCID: PMC6873202 DOI: 10.1074/jbc.ra119.010201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/30/2019] [Indexed: 01/07/2023] Open
Abstract
WT P53-Induced Phosphatase 1 (WIP1) is a member of the magnesium-dependent serine/threonine protein phosphatase (PPM) family and is induced by P53 in response to DNA damage. In several human cancers, the WIP1 protein is overexpressed, which is generally associated with a worse prognosis. Although WIP1 is an attractive therapeutic target, no potent, selective, and bioactive small-molecule modulator with favorable pharmacokinetics has been reported. Phosphatase enzymes are among the most challenging targets for small molecules because of the difficulty of achieving both modulator selectivity and bioavailability. Another major obstacle has been the availability of robust and physiologically relevant phosphatase assays that are suitable for high-throughput screening. Here, we describe orthogonal biochemical WIP1 activity assays that utilize phosphopeptides from native WIP1 substrates. We optimized an MS assay to quantify the enzymatically dephosphorylated peptide reaction product in a 384-well format. Additionally, a red-shifted fluorescence assay was optimized in a 1,536-well format to enable real-time WIP1 activity measurements through the detection of the orthogonal reaction product, Pi. We validated these two optimized assays by quantitative high-throughput screening against the National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection and used secondary assays to confirm and evaluate inhibitors identified in the primary screen. Five inhibitors were further tested with an orthogonal WIP1 activity assay and surface plasmon resonance binding studies. Our results validate the application of miniaturized physiologically relevant and orthogonal WIP1 activity assays to discover small-molecule modulators from high-throughput screens.
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Affiliation(s)
- Victor Clausse
- Synthetic Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Subrata Debnath
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Yuhong Fang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Harichandra D Tagad
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Yuhong Wang
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Hongmao Sun
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Christopher A LeClair
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Sharlyn J Mazur
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Kelly Lane
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Zhen-Dan Shi
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Olga Vasalatiy
- Imaging Probe Development Center, NHLBI, National Institutes of Health, Rockville, Maryland 20850
| | - Rebecca Eells
- Reaction Biology Corporation, 1 Great Valley Parkway, Suite 2, Malvern, Pennsylvania 19355
| | - Lynn K Baker
- Reaction Biology Corporation, 1 Great Valley Parkway, Suite 2, Malvern, Pennsylvania 19355
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Martin R Webb
- Francis Crick Institute, 1 Midland Road, London NW1 AT, United Kingdom
| | - Min Shen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Matthew D Hall
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
| | - Ettore Appella
- Laboratory of Cell Biology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Daniel H Appella
- Synthetic Bioactive Molecules Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, Bethesda, Maryland 20892
| | - Nathan P Coussens
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850
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Zhou W, Yin Y, Weinheimer AS, Kaur N, Carpino N, French JB. Structural and Functional Characterization of the Histidine Phosphatase Domains of Human Sts-1 and Sts-2. Biochemistry 2017; 56:4637-4645. [PMID: 28759203 DOI: 10.1021/acs.biochem.7b00638] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The suppressor of T cell signaling (Sts) proteins, Sts-1 and Sts-2, are homologous phosphatases that negatively regulate signaling pathways downstream of the T cell receptor. Functional inactivation of Sts-1 and Sts-2 in a murine model leads to resistance to systemic infection by the opportunistic pathogen, Candida albicans. This suggests that modulation of the host immune response by inhibiting Sts function may be a viable strategy for treating these deadly fungal pathogen infections. To better understand the molecular determinants of function and structure, we characterized the structure and steady-state kinetics of the histidine phosphatase domains of human Sts-1 (Sts-1HP) and Sts-2 (Sts-2HP). We determined the X-ray crystal structures of unliganded Sts-1HP and Sts-1HP in complex with sulfate to 2.5 and 1.9 Å, respectively, and the structure of Sts-2HP with sulfate to 2.4 Å. The steady-state kinetic analysis shows, as expected, that Sts-1HP has a phosphatase activity significantly higher than that of Sts-2HP and that the human and mouse proteins behave similarly. In addition, comparison of the phosphatase activity of full-length Sts-1 protein to Sts-1HP reveals similar kinetics, indicating that Sts-1HP is a functional surrogate for the native protein. We also tested known phosphatase inhibitors and determined that the SHP-1 inhibitor, PHPS1, is a potent inhibitor of Sts-1 (Ki = 1.05 ± 0.15 μM). Finally, we demonstrated that human Sts-1 has robust phosphatase activity against the substrate, Zap-70, in a cell-based assay. Collectively, these data suggest that the human Sts proteins are druggable targets and provide a structural basis for future drug development efforts.
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Affiliation(s)
- Weijie Zhou
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Yue Yin
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Alexandra S Weinheimer
- Department of Biochemistry and Cell Biology, Stony Brook University , Stony Brook, New York 11794, United States
| | - Neena Kaur
- Department of Molecular Genetics and Microbiology, Stony Brook University , Stony Brook, New York 11794, United States
| | - Nick Carpino
- Department of Molecular Genetics and Microbiology, Stony Brook University , Stony Brook, New York 11794, United States
| | - Jarrod B French
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States.,Department of Biochemistry and Cell Biology, Stony Brook University , Stony Brook, New York 11794, United States
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