1
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Liechty ET, Hren A, Kramer L, Donovan G, Friedman AJ, Shirts MR, Fox JM. Analysis of neutral mutational drift in an allosteric enzyme. Protein Sci 2023; 32:e4719. [PMID: 37402140 PMCID: PMC10364584 DOI: 10.1002/pro.4719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/05/2023]
Abstract
Neutral mutational drift is an important source of biological diversity that remains underexploited in fundamental studies of protein biophysics. This study uses a synthetic transcriptional circuit to study neutral drift in protein tyrosine phosphatase 1B (PTP1B), a mammalian signaling enzyme for which conformational changes are rate limiting. Kinetic assays of purified mutants indicate that catalytic activity, rather than thermodynamic stability, guides enrichment under neutral drift, where neutral or mildly activating mutations can mitigate the effects of deleterious ones. In general, mutants show a moderate activity-stability tradeoff, an indication that minor improvements in the activity of PTP1B do not require concomitant losses in its stability. Multiplexed sequencing of large mutant pools suggests that substitutions at allosterically influential sites are purged under biological selection, which enriches for mutations located outside of the active site. Findings indicate that the positional dependence of neutral mutations within drifting populations can reveal the presence of allosteric networks and illustrate an approach for using synthetic transcriptional systems to explore these mutations in regulatory enzymes.
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Affiliation(s)
- Evan T. Liechty
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Andrew Hren
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Levi Kramer
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Gregory Donovan
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Anika J. Friedman
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Michael R. Shirts
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
| | - Jerome M. Fox
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderColoradoUSA
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2
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Morris R, Keating N, Tan C, Chen H, Laktyushin A, Saiyed T, Liau NPD, Nicola NA, Tiganis T, Kershaw NJ, Babon JJ. Structure guided studies of the interaction between PTP1B and JAK. Commun Biol 2023; 6:641. [PMID: 37316570 DOI: 10.1038/s42003-023-05020-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/06/2023] [Indexed: 06/16/2023] Open
Abstract
Protein Tyrosine Phosphatase 1B (PTP1B) is the prototypical protein tyrosine phosphatase and plays an essential role in the regulation of several kinase-driven signalling pathways. PTP1B displays a preference for bisphosphorylated substrates. Here we identify PTP1B as an inhibitor of IL-6 and show that, in vitro, it can dephosphorylate all four members of the JAK family. In order to gain a detailed understanding of the molecular mechanism of JAK dephosphorylation, we undertook a structural and biochemical analysis of the dephosphorylation reaction. We identified a product-trapping PTP1B mutant that allowed visualisation of the tyrosine and phosphate products of the reaction and a substrate-trapping mutant with a vastly decreased off-rate compared to those previously described. The latter mutant was used to determine the structure of bisphosphorylated JAK peptides bound to the enzyme active site. These structures revealed that the downstream phosphotyrosine preferentially engaged the active site, in contrast to the analogous region of IRK. Biochemical analysis confirmed this preference. In this binding mode, the previously identified second aryl binding site remains unoccupied and the non-substrate phosphotyrosine engages Arg47. Mutation of this arginine disrupts the preference for the downstream phosphotyrosine. This study reveals a previously unappreciated plasticity in how PTP1B interacts with different substrates.
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Affiliation(s)
- Rhiannon Morris
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Narelle Keating
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Cyrus Tan
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Hao Chen
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Artem Laktyushin
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
| | - Tamanna Saiyed
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
| | - Nicholas P D Liau
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Nicos A Nicola
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Tony Tiganis
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, 3800, Australia
- Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, VIC, 3000, Australia
| | - Nadia J Kershaw
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia
| | - Jeffrey J Babon
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, VIC, Australia.
- Department of Medical Biology, The University of Melbourne, Royal Parade, Parkville, 3052, VIC, Australia.
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3
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Papaioannou A, Centonze F, Metais A, Maurel M, Negroni L, Gonzalez-Quiroz M, Mahdizadeh SJ, Svensson G, Zare E, Blondel A, Koong AC, Hetz C, Pedeux R, Tremblay ML, Eriksson LA, Chevet E. Stress-induced tyrosine phosphorylation of RtcB modulates IRE1 activity and signaling outputs. Life Sci Alliance 2022; 5:e202201379. [PMID: 35193953 PMCID: PMC8899846 DOI: 10.26508/lsa.202201379] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 12/18/2022] Open
Abstract
ER stress is mediated by three sensors and the most evolutionary conserved IRE1α signals through its cytosolic kinase and endoribonuclease (RNase) activities. IRE1α RNase activity can either catalyze the initial step of XBP1 mRNA unconventional splicing or degrade a number of RNAs through regulated IRE1-dependent decay. Until now, the biochemical and biological outputs of IRE1α RNase activity have been well documented; however, the precise mechanisms controlling whether IRE1α signaling is adaptive or pro-death (terminal) remain unclear. We investigated those mechanisms and hypothesized that XBP1 mRNA splicing and regulated IRE1-dependent decay activity could be co-regulated by the IRE1α RNase regulatory network. We identified that RtcB, the tRNA ligase responsible for XBP1 mRNA splicing, is tyrosine-phosphorylated by c-Abl and dephosphorylated by PTP1B. Moreover, we show that the phosphorylation of RtcB at Y306 perturbs RtcB interaction with IRE1α, thereby attenuating XBP1 mRNA splicing. Our results demonstrate that the IRE1α RNase regulatory network is dynamically fine-tuned by tyrosine kinases and phosphatases upon various stresses and that the extent of RtcB tyrosine phosphorylation determines cell adaptive or death outputs.
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Affiliation(s)
- Alexandra Papaioannou
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Federica Centonze
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Alice Metais
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Marion Maurel
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Luc Negroni
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Matías Gonzalez-Quiroz
- INSERM U1242, University of Rennes, Rennes, France
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | | | - Gabriella Svensson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Ensieh Zare
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Alice Blondel
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Albert C Koong
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Rémy Pedeux
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Michel L Tremblay
- Goodman Cancer Research Centre, McGill University, Montreal, Canada
- Department of Biochemistry, McGill University, Montreal, Canada
| | - Leif A Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Eric Chevet
- INSERM U1242, University of Rennes, Rennes, France
- Centre Eugène Marquis, Rennes, France
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4
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Harris JW, Bates JS, Bukowski BC, Greeley J, Gounder R. Opportunities in Catalysis over Metal-Zeotypes Enabled by Descriptions of Active Centers Beyond Their Binding Site. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02102] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- James W. Harris
- Department of Chemical and Biological Engineering, The University of Alabama, Box 870203, Tuscaloosa, Alabama 35487, United States
| | - Jason S. Bates
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Brandon C. Bukowski
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Jeffrey Greeley
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Rajamani Gounder
- Charles D. Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
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5
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Cui DS, Lipchock JM, Brookner D, Loria JP. Uncovering the Molecular Interactions in the Catalytic Loop That Modulate the Conformational Dynamics in Protein Tyrosine Phosphatase 1B. J Am Chem Soc 2019; 141:12634-12647. [PMID: 31339043 DOI: 10.1021/jacs.9b04470] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Active-site loops are integral to the function of numerous enzymes. They enable substrate and product binding and release, sequester reaction intermediates, and recruit catalytic groups. Here, we examine the catalytic loop in the enzyme protein tyrosine phosphatase 1B (PTP1B). PTP1B has a mobile so-called WPD loop (named for its three N-terminal residues) that initiates the dephosphorylation of phosphor-tyrosine substrates upon loop closure. We have combined X-ray crystallography, solution NMR, and pre-steady-state kinetics experiments on wild-type and five WPD loop mutants to identify the relationships between the loop structure, dynamics, and function. The motions of the WPD loop are modulated by the formation of weak molecular interactions, where perturbations of these interactions modulate the conformational equilibrium landscape. The point mutants in the WPD loop alter the loop equilibrium position from a predominantly open state (P185A) to 50:50 (F182A), 35:65 (P188A), and predominantly closed states (T177A and P188A). Surprisingly, there is no correlation between the observed catalytic rates in the loop mutants and changes to the WPD loop equilibrium position. Rather, we observe a strong correlation between the rate of dephosphorylation of the phosphocysteine enzyme intermediate and uniform millisecond motions, not only within the loop but also in the adjacent α-helical domain of PTP1B. Thus, the control of loop motion and thereby catalytic activity is dispersed and resides within not only the loop sequence but also the surrounding protein architecture. This has broad implications for the general mechanistic understanding of enzyme reactions and the role that flexible loops play in the catalytic cycle.
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Affiliation(s)
- Danica S Cui
- Department of Chemistry , Yale University , New Haven , Connecticut 06511 , United States
| | - James Michael Lipchock
- Department of Chemistry , Washington College , Chestertpwm , Maryland 21620 , United States
| | - Dennis Brookner
- Department of Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06511 , United States
| | - J Patrick Loria
- Department of Chemistry , Yale University , New Haven , Connecticut 06511 , United States.,Department of Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06511 , United States
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6
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Tang H, Dai Z, Qin X, Cai W, Hu L, Huang Y, Cao W, Yang F, Wang C, Liu T. Proteomic Identification of Protein Tyrosine Phosphatase and Substrate Interactions in Living Mammalian Cells by Genetic Encoding of Irreversible Enzyme Inhibitors. J Am Chem Soc 2018; 140:13253-13259. [PMID: 30247891 DOI: 10.1021/jacs.8b06922] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Protein tyrosine phosphatases (PTPs) play critical roles in cell signaling pathways, but identification of unknown PTPs for a given substrate in live cells remain technically challenging. Here, we synthesized a series of tyrosine-based irreversible PTP inhibitors and characterized by site-specific encoding on substrate proteins in cells with an expanded genetic code. By fine-tuning the chemical reactivity, we identified optimal active amino acid probes to covalently cross-link a PTP and its substrate both in vitro and in mammalian cells. Using HER2 as an example, we provide first direct evidence of HER2 Y1023 and SHP2 cross-linking in situ in living human cells. Moreover, proteomic analysis using our approach identified PTP1B as a novel phosphatase for HER2 that specifically dephosphorylated pY1221 position, which may shed light on the puzzle of PTP1B's role in HER2 positive breast cancer. This novel method provides a useful tool for dissecting tyrosine phosphoregulation in living cells.
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Affiliation(s)
- Hongting Tang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
| | - Zhen Dai
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China.,College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry , Nankai University , Tianjin 300071 , China
| | - Xuewen Qin
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
| | - Wenkang Cai
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
| | - Liming Hu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
| | - Yujia Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
| | - Wenbing Cao
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China.,College of Chemistry, State Key Laboratory of Elemento-Organic Chemistry , Nankai University , Tianjin 300071 , China
| | - Fan Yang
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Chu Wang
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | - Tao Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences , Peking University , 38 Xueyuan Road , Haidian District, Beijing 100191 , China
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7
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Protein Clusters in Phosphotyrosine Signal Transduction. J Mol Biol 2018; 430:4547-4556. [PMID: 29870724 DOI: 10.1016/j.jmb.2018.05.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/08/2018] [Accepted: 05/28/2018] [Indexed: 11/20/2022]
Abstract
Signal transduction systems based on tyrosine phosphorylation are central to cell-cell communication in multicellular organisms. Typically, in such a system, the signal is initiated by activating tyrosine kinases associated with transmembrane receptors, which induces tyrosine phosphorylation of the receptor and/or associated proteins. The phosphorylated tyrosines then serve as docking sites for the binding of various downstream effector proteins. It has long been observed that the cooperative association of the receptors and effectors produces higher-order protein assemblies (clusters) following signal activation in virtually all phosphotyrosine signal transduction systems. However, mechanistic studies on how such clustering processes affect signal transduction outcomes have only emerged recently. Here we review current progress in decoding the biophysical consequences of clustering on the behavior of the system, and how clustering affects how these receptors process information.
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8
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Ruddraraju KV, Zhang ZY. Covalent inhibition of protein tyrosine phosphatases. MOLECULAR BIOSYSTEMS 2018; 13:1257-1279. [PMID: 28534914 DOI: 10.1039/c7mb00151g] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protein tyrosine phosphatases (PTPs) are a large family of 107 signaling enzymes that catalyze the hydrolytic removal of phosphate groups from tyrosine residues in a target protein. The phosphorylation status of tyrosine residues on proteins serve as a ubiquitous mechanism for cellular signal transduction. Aberrant function of PTPs can lead to many human diseases, such as diabetes, obesity, cancer, and autoimmune diseases. As the number of disease relevant PTPs increases, there is urgency in developing highly potent inhibitors that are selective towards specific PTPs. Most current efforts have been devoted to the development of active site-directed and reversible inhibitors for PTPs. This review summarizes recent progress made in the field of covalent inhibitors to target PTPs. Here, we discuss the in vivo and in vitro inactivation of various PTPs by small molecule-containing electrophiles, such as Michael acceptors, α-halo ketones, epoxides, and isothiocyanates, etc. as well as oxidizing agents. We also suggest potential strategies to transform these electrophiles into isozyme selective covalent PTP inhibitors.
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Affiliation(s)
- Kasi Viswanatharaju Ruddraraju
- Department of Medicinal Chemistry and Molecular Pharmacology, Department of Chemistry, Center for Cancer Research, and Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, IN 47907, USA.
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9
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Radha V. Use of Dominant-Negative/Substrate Trapping PTP Mutations to Search for PTP Interactors/Substrates. Methods Mol Biol 2016; 1447:243-65. [PMID: 27514810 DOI: 10.1007/978-1-4939-3746-2_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Phosphorylation of proteins on tyrosine residues is the consequence of coordinated action of tyrosine kinases (TKs), and protein tyrosine phosphatases (PTPs). Together, they regulate intermolecular interactions, subcellular localization, and activity of a variety of proteins. The level of total protein-associated tyrosine phosphorylation in eukaryotic cells is only a small fraction of the total phosphorylation. PTPs, which have high specific activity compared to tyrosine kinases, play an important role in maintaining the tyrosine phosphorylation state of proteins and regulate signal transduction pathways and cellular responses. PTPs depend on specific invariant residues that enable binding to substrates phosphorylated at tyrosine and aid catalytic activity. Identification of PTP substrates has helped understand their role in distinct intracellular signaling pathways. Because of their high specific activity, the interaction between tyrosine phosphatases and their substrates is often very transient in the cellular context, and therefore identification of physiological substrates has been difficult. Single-site mutations in the enzymes stabilize interaction between the enzyme and its targets and have been used extensively to identify substrates. The mutations are either of the catalytic cysteine (Cys) residue or other invariant residues and have been classified as substrate-trapping mutants (STMs). These mutants often serve as dominant negatives that can inactivate effector functions of a specific PTP within cells. Considering their association with human disorders, inhibiting specific PTPs is important therapeutically. Since the catalytic domains are largely conserved, developing small-molecule inhibitors to a particular enzyme has proven difficult and therefore alternate strategies to block functions of individual enzymes are seriously being investigated. We provide a description of methods that will be useful to design strategies of using dominant-negative and substrate-trapping mutants for identifying novel interacting partners and substrates of PTPs.
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Affiliation(s)
- Vegesna Radha
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India.
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10
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Ahuja LG, Gopal B. Bi-domain protein tyrosine phosphatases reveal an evolutionary adaptation to optimize signal transduction. Antioxid Redox Signal 2014; 20:2141-59. [PMID: 24206235 DOI: 10.1089/ars.2013.5721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE The bi-domain protein tyrosine phosphatases (PTPs) exemplify functional evolution in signaling proteins for optimal spatiotemporal signal transduction. Bi-domain PTPs are products of gene duplication. The catalytic activity, however, is often localized to one PTP domain. The inactive PTP domain adopts multiple functional roles. These include modulation of catalytic activity, substrate specificity, and stability of the bi-domain enzyme. In some cases, the inactive PTP domain is a receptor for redox stimuli. Since multiple bi-domain PTPs are concurrently active in related cellular pathways, a stringent regulatory mechanism and selective cross-talk is essential to ensure fidelity in signal transduction. RECENT ADVANCES The inactive PTP domain is an activator for the catalytic PTP domain in some cases, whereas it reduces catalytic activity in other bi-domain PTPs. The relative orientation of the two domains provides a conformational rationale for this regulatory mechanism. Recent structural and biochemical data reveal that these PTP domains participate in substrate recruitment. The inactive PTP domain has also been demonstrated to undergo substantial conformational rearrangement and oligomerization under oxidative stress. CRITICAL ISSUES AND FUTURE DIRECTIONS The role of the inactive PTP domain in coupling environmental stimuli with catalytic activity needs to be further examined. Another aspect that merits attention is the role of this domain in substrate recruitment. These aspects have been poorly characterized in vivo. These lacunae currently restrict our understanding of neo-functionalization of the inactive PTP domain in the bi-domain enzyme. It appears likely that more data from these research themes could form the basis for understanding the fidelity in intracellular signal transduction.
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Affiliation(s)
- Lalima Gagan Ahuja
- 1 Molecular Biophysics Unit, Indian Institute of Science , Bangalore, India
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11
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Luo Y, Yogesha SD, Cannon JR, Yan W, Ellington AD, Brodbelt JS, Zhang Y. novel modifications on C-terminal domain of RNA polymerase II can fine-tune the phosphatase activity of Ssu72. ACS Chem Biol 2013; 8:2042-52. [PMID: 23844594 DOI: 10.1021/cb400229c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C-terminal domain of RNA polymerase II (CTD) modulates the process of transcription through sequential phosphorylation/dephosphorylation of its heptide repeats, through which it recruits various transcription regulators. Ssu72 is the first characterized cis-specific CTD phosphatase that dephosphorylates Ser5 with a requirement for the adjacent Pro6 in a cis conformation. The recent discovery of Thr4 phosphorylation in the CTD calls into question whether such a modification can interfere with Ssu72 binding via the elimination of a conserved intramolecular hydrogen bond in the CTD that is potentially essential for recognition. To test if Thr4 phosphorylation will abolish Ser5 dephosphorylation by Ssu72, we determined the kinetic and structural properties of Drosophila Ssu72-symplekin in complex with the CTD peptide with consecutive phosphorylated Thr4 and Ser5. Our mass spectrometric and kinetic data established that Ssu72 does not dephosphorylate Thr4, but the existence of phosphoryl-Thr4 next to Ser5 reduces the activity of Ssu72 toward the CTD peptide by 4-fold. To our surprise, even though the intramolecular hydrogen bond is eliminated due to the phosphorylation of Thr4, the CTD adopts an almost identical conformation to be recognized by Ssu72 with Ser5 phosphorylated alone or both Thr4/Ser5 phosphorylated. Our results indicate that Thr4 phosphorylation will not abolish the essential Ssu72 activity, which is needed for cell survival. Instead, the phosphatase activity of Ssu72 is fine-tuned by Thr4 phosphorylation and eventually may lead to changes in transcription. Overall, we report the first case of structural and kinetic effects of phosphorylated Thr4 on CTD modifying enzymes. Our results support a model in which a combinatorial cascade of CTD modification can modulate transcription.
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Affiliation(s)
- Yonghua Luo
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - S. D. Yogesha
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Joe R. Cannon
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Wupeng Yan
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Andrew D. Ellington
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Jennifer S. Brodbelt
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
| | - Yan Zhang
- Department
of Chemistry and Biochemistry and ‡Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin,
Texas 78712, United States
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12
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Hogan M, Bahta M, Cherry S, Lountos GT, Tropea JE, Zhao BM, Burke TR, Waugh DS, Ulrich RG. Biomolecular Interactions of small-molecule inhibitors affecting the YopH protein tyrosine phosphatase. Chem Biol Drug Des 2013; 81:323-33. [PMID: 23241354 PMCID: PMC3573263 DOI: 10.1111/cbdd.12097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have developed competitive and direct binding methods to examine small-molecule inhibitors of protein tyrosine phosphatase activity. Focusing on the Yersinia pestis outer protein H, a potent bacterial protein tyrosine phosphatase, we describe how an understanding of the kinetic interactions involving Yersinia pestis outer protein H, peptide substrates, and small-molecule inhibitors of protein tyrosine phosphatase activity can be beneficial for inhibitor screening, and we further translate these results into a microarray assay for high-throughput screening.
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Affiliation(s)
- Megan Hogan
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, United States
| | - Medhanit Bahta
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Scott Cherry
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Lab, Frederick, Maryland 21702, United States
| | - George T. Lountos
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Lab, Frederick, Maryland 21702, United States
- Basic Science Program, SAIC-Frederick, Inc., Frederick National Lab, Frederick, Maryland 21702, United States
| | - Joseph E. Tropea
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Lab, Frederick, Maryland 21702, United States
| | - Bryan M. Zhao
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, United States
| | - Terrence R. Burke
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - David S. Waugh
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick National Lab, Frederick, Maryland 21702, United States
| | - Robert G. Ulrich
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, United States
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13
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Gledhill AC, Cosgrove NE, Nixon TD, Kilner CA, Fisher J, Kee TP. Asymmetric general base catalysis of the phospho-aldol reaction via dimeric aluminium hydroxides. Dalton Trans 2010; 39:9472-5. [DOI: 10.1039/c0dt00459f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Hsu S, Kim Y, Li S, Durrant ES, Pace RM, Woods VL, Gentry MS. Structural insights into glucan phosphatase dynamics using amide hydrogen-deuterium exchange mass spectrometry. Biochemistry 2009; 48:9891-902. [PMID: 19754155 DOI: 10.1021/bi9008853] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Laforin and starch excess 4 (SEX4) are founding members of a class of phosphatases that dephosphorylate phosphoglucans. Each protein contains a carbohydrate binding module (CBM) and a dual-specificity phosphatase (DSP) domain. The gene encoding laforin is mutated in a fatal neurodegenerative disease called Lafora disease (LD). In the absence of laforin function, insoluble glucans that are hyperphosphorylated and exhibit sparse branching accumulate. It is hypothesized that these accumulations trigger the neurodegeneration and premature death of LD patients. We recently demonstrated that laforin removes phosphate from phosphoglucans and hypothesized that this function inhibits insoluble glucan accumulation. Loss of SEX4 function in plants yields a similar cellular phenotype; an excess amount of insoluble, hyperphosphorylated glucans accumulates in cells. While multiple groups have shown that these phosphatases dephosphorylate phosphoglucans, there is no structure of a glucan phosphatase and little is known about the mechanism whereby they perform this action. We utilized hydrogen-deuterium exchange mass spectrometry (DXMS) and structural modeling to probe the conformational and structural dynamics of the glucan phosphatase SEX4. We found that the enzyme does not undergo a global conformational change upon glucan binding but instead undergoes minimal rearrangement upon binding. The CBM has improved protection from deuteration when bound to glucans, confirming its role in glucan binding. More interestingly, we identified structural components of the DSP that also have improved protection from deuteration upon glucan addition. To determine the position of these regions, we generated a homology model of the SEX4 DSP. The homology model shows that all of these regions are adjacent to the DSP active site. Therefore, our results suggest that these regions of the DSP participate in the presentation of the phosphoglucan to the active site and provide the first structural analysis and mode of action of this unique class of phosphatases.
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Affiliation(s)
- Simon Hsu
- Department of Medicine, University of California at San Diego, La Jolla, California 92093-0601, USA
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15
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Zhou B, Zhang ZY. Application of hydrogen/deuterium exchange mass spectrometry to study protein tyrosine phosphatase dynamics, ligand binding, and substrate specificity. Methods 2007; 42:227-33. [PMID: 17532509 PMCID: PMC2001256 DOI: 10.1016/j.ymeth.2007.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 02/13/2007] [Indexed: 01/27/2023] Open
Abstract
Protein tyrosine phosphatases (PTPs) are signaling enzymes that control a diverse array of cellular processes. Further insight into the specific functional roles of PTPs in cellular signaling requires detailed understanding of the molecular basis for substrate recognition by the PTPs. A central question is how PTPs discriminate between multiple structurally diverse substrates that they encounter in the cell. Although X-ray crystallography is capable of revealing the intimate structural details for molecular interaction, structures of higher order PTP.substrate complexes are often difficult to obtain. Hydrogen/deuterium exchange mass spectrometry (H/DX-MS) is a powerful tool for mapping protein-protein interfaces, as well as identifying conformational and dynamic perturbations in proteins. In addition, H/DX-MS enables analysis of large protein complexes at physiological concentrations and provides insight into the solution behavior of these complexes that can not be gleaned from crystal structures. We have utilized H/DX-MS to probe PTP dynamics, ligand binding, and the structural basis of substrate recognition. In this article, we review general principles of H/DX-MS technology as applied to study protein-protein interactions and dynamics. We also provide protocols for H/DX-MS successfully used in our laboratory to define the molecular basis of ERK2 substrate recognition by MKP3. Many of the aspects that we cover in detail should be applicable to the study of other PTPs with their specific targets.
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Affiliation(s)
- Bo Zhou
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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16
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Zhang S, Chen L, Kumar S, Wu L, Lawrence DS, Zhang ZY. An affinity-based fluorescence polarization assay for protein tyrosine phosphatases. Methods 2007; 42:261-7. [PMID: 17532513 PMCID: PMC2001261 DOI: 10.1016/j.ymeth.2007.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2007] [Indexed: 10/23/2022] Open
Abstract
Protein tyrosine phosphatases (PTPs) are important signaling enzymes that control such fundamental processes as proliferation, differentiation, survival/apoptosis, as well as adhesion and motility. Potent and selective PTP inhibitors serve not only as powerful research tools, but also as potential therapeutics against a variety illness including cancer and diabetes. PTP activity-based assays are widely used in high throughput screening (HTS) campaigns for PTP inhibitor discovery. These assays suffer from a major weakness, in that the reactivity of the active site Cys can cause serious problems as highly reactive oxidizing and alkylating agents may surface as hits. We describe the development of a fluorescence polarization (FP)-based displacement assay that makes the use of an active site Cys to Ser mutant PTP (e.g., PTP1B/C215S) that retains the wild-type binding affinity. The potency of library compounds is assessed by their ability to compete with the fluorescently labeled active site ligand for binding to the Cys to Ser PTP mutant. Finally, the substitution of the active site Cys by a Ser renders the mutant PTP insensitive to oxidation and alkylation and thus will likely eliminate "false" positives due to modification of the active site Cys that destroy the phosphatase activity.
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Affiliation(s)
- Sheng Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202
| | - Lan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202
| | - Sanjai Kumar
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Li Wu
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202
| | - David S. Lawrence
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202
- Corresponding author: Phone: (317) 274-8025, Fax: (317) 274-4686, E-mail:
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17
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Zhang YL, Tam M, Kirincich S, Wan ZK, Wilson D, Wu JJ, Lee J, Tobin JF, Erbe DV. An enzyme-linked immunosorbent assay to measure insulin receptor dephosphorylation by PTP1B. Anal Biochem 2007; 365:174-84. [PMID: 17481567 DOI: 10.1016/j.ab.2007.03.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/26/2007] [Accepted: 03/28/2007] [Indexed: 11/29/2022]
Abstract
Considerable effort exists within drug discovery to develop novel compounds to improve the underlying metabolic defects in type 2 diabetes. One approach is focused on inhibition of the tyrosine phosphatase, PTP1B, an important negative regulator of both insulin and leptin signaling. Historically, tyrosine phosphatase assays have used either small organic phosphates or, alternatively, phosphorylated peptides from the target proteins themselves. In characterizing inhibitors of PTP1B, measuring turnover of small organic phosphates is limited to evaluation of compounds that bind the active site itself. Peptide substrates allow identification of additional subsets of inhibitors (e.g., those that bind the second aryl-phosphate site), but assays of peptide turnover often involve detection steps that then limit full kinetic evaluation of inhibitors. Here we use a polyclonal antibody specific for the phosphorylated insulin receptor to allow much more sensitive detection of peptide phosphorylation. This kinetically robust enzyme-linked immunosorbent assay (ELISA) gives k(cat) and K(m) values for a phosphorylated insulin receptor peptide consistent with values determined by a continuous fluorescence-based assay. Furthermore, IC50 values determined for well-behaved active site inhibitors agree well with values determined for p-nitrophenyl phosphate cleavage. This assay permits full characterization of a larger subset of inhibitors as drug candidates for this promising target.
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Affiliation(s)
- Yan-Ling Zhang
- Cardiovascular and Metabolic Diseases, Wyeth Research, Cambridge, MA 02140, USA
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18
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Liang F, Kumar S, Zhang ZY. Proteomic approaches to studying protein tyrosine phosphatases. MOLECULAR BIOSYSTEMS 2007; 3:308-16. [PMID: 17460790 DOI: 10.1039/b700704n] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Protein tyrosine phosphatases (PTPs) constitute a large family of enzymes that play key roles in cell signaling. Deregulation of PTP activity results in aberrant tyrosine phosphorylation, which has been linked to the etiology of several human diseases, including cancer. Since phosphate removal by the PTPs can both enhance and antagonize cellular signaling, it is essential to elucidate the physiological context in which PTPs operate. Two powerful proteomic approaches have been developed to rapidly establish the exact functional roles for every PTP, both in normal cellular physiology and in pathogenic conditions. In the first, an affinity-based substrate-trapping approach has been employed for PTP substrate identification. Identification and characterization of specific PTP-substrate interactions will associate functions with PTP as well as implicate PTP to specific signaling pathways. In the second, a number of activity-based PTP probes have been developed that can provide a direct readout of the functional state of the PTPs in complex proteomes. The ability to profile the entire PTP family on the basis of changes in their activity is expected to yield new functional insights into pathways regulated by the PTPs and contribute to the discovery of PTPs as novel therapeutic targets. Effective application of these proteomic techniques will accelerate the functional characterization of PTPs, thereby facilitating our understanding of PTPs in cell signaling and in diseases.
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Affiliation(s)
- Fubo Liang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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19
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Zhou B, Zhang J, Liu S, Reddy S, Wang F, Zhang ZY. Mapping ERK2-MKP3 Binding Interfaces by Hydrogen/Deuterium Exchange Mass Spectrometry. J Biol Chem 2006; 281:38834-44. [PMID: 17046812 DOI: 10.1074/jbc.m608916200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
ERK2, a prototypic member of the MAPK family, plays a central role in regulating cell growth and differentiation. MKP3, an ERK2-specific phosphatase, terminates ERK2 signaling. To understand the molecular basis of ERK2 recognition by MKP3, we carried out hydrogen/deuterium exchange mass spectrometry experiments to map the interaction surfaces between the two proteins. The results show that the exquisite specificity of MKP3 for ERK2 is governed by two distinctive protein-protein interactions. To increase the "effective concentration" of the interacting molecules, the kinase interaction motif in MKP3 ((64)RRLQKGNLPVR(74)) and an MKP3-specific segment ((101)NSSDWNE(107)) bind the common docking site in ERK2 defined by residues in L(16), L(5), beta(7)-beta(8), and alpha(d)-L(8)-alpha(e), located opposite the kinase active site. In addition to this "tethering" effect, additional interactions between the (364)FTAP(367) sequence in MKP3 and the ERK2 substrate-binding site, formed by residues in the activation lip and the P+1 site (beta(9)-alpha(f) loop), L(13) (alpha(f)-alpha(g) loop), and the MAPK insert (L(14)-alpha(1L14)-alpha(2L14)), are essential for allosteric activation of MKP3 and formation of a productive complex whereby the MKP3 catalytic site is correctly juxtaposed to carry out the dephosphorylation of phospho-Thr(183)/phospho-Tyr(185) in ERK2. This bipartite protein-protein interaction model may be applicable to the recognition of other MAPKs by their cognate regulators and substrates.
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Affiliation(s)
- Bo Zhou
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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20
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Arantes GM. Free-energy profiles for catalysis by dual-specificity phosphatases. Biochem J 2006; 399:343-50. [PMID: 16784417 PMCID: PMC1609924 DOI: 10.1042/bj20060637] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2006] [Revised: 06/19/2006] [Accepted: 06/20/2006] [Indexed: 11/17/2022]
Abstract
PTPs (protein tyrosine phosphatases) are fundamental enzymes for cell signalling and have been linked to the pathogenesis of several diseases, including cancer. Hence, PTPs are potential drug targets and inhibitors have been designed as possible therapeutic agents for Type II diabetes and obesity. However, a complete understanding of the detailed catalytic mechanism in PTPs is still lacking. Free-energy profiles, obtained by computer simulations of catalysis by a dual-specificity PTP, are shown in the present study and are used to shed light on the catalytic mechanism. A highly accurate hybrid potential of quantum mechanics/molecular mechanics calibrated specifically for PTP reactions was used. Reactions of alkyl and aryl substrates, with different protonation states and PTP active-site mutations, were simulated. Calculated reaction barriers agree well with experimental rate measurements. Results show the PTP substrate reacts as a bi-anion, with an ionized nucleophile. This protonation state has been a matter of debate in the literature. The inactivity of Cys-->Ser active-site mutants is also not fully understood. It is shown that mutants are inactive because the serine nucleophile is protonated. Results also clarify the interpretation of experimental data, particularly kinetic isotope effects. The simulated mechanisms presented here are better examples of the catalysis carried out by PTPs.
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Key Words
- computer simulation
- enzyme mechanism
- hybrid potential
- phosphate ester
- protein phosphatase
- ds-ptp, dual-specificity protein tyrosine phosphatase
- kie, kinetic isotope effect
- lm-ptp, low-molecular-mass protein tyrosine phosphatase
- mc, michaelis complex
- ph, phenyl
- ptp, protein tyrosine phosphatase
- qm/mm, quantum mechanical/molecular mechanical
- rmsd, root mean squared deviation
- ts, transition state
- vhr, vaccinia vh1-related
- wt, wild-type
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Affiliation(s)
- Guilherme M Arantes
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Lineu Prestes 748, 05508-900, São Paulo, SP, Brazil.
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21
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. YLZ, . JFT, . DVE. PTP1b: A Promising and Challenging Target for Metabolic Disease. INT J PHARMACOL 2005. [DOI: 10.3923/ijp.2006.93.97] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Fukada M, Kawachi H, Fujikawa A, Noda M. Yeast substrate-trapping system for isolating substrates of protein tyrosine phosphatases: Isolation of substrates for protein tyrosine phosphatase receptor type z. Methods 2005; 35:54-63. [PMID: 15588986 DOI: 10.1016/j.ymeth.2004.07.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2004] [Indexed: 11/23/2022] Open
Abstract
Although members of the protein tyrosine phosphatase (PTP) family are known to play critical roles in various cellular processes through the regulation of protein tyrosine phosphorylation in cooperation with protein tyrosine kinases (PTKs), the physiological functions of individual PTPs are poorly understood. This is due to a lack of information concerning the physiological substrates of the respective PTPs. Several years ago, substrate-trap mutants were developed to identify the substrates of PTPs, but only a limited number of PTP substrates have been identified using typical biochemical techniques in vitro. The application of this strategy to all the PTPs seems difficult, because the substrates identified to date were restricted to relatively abundant and highly tyrosine phosphorylated cellular proteins. Therefore, the development of a standard method applicable to all PTPs has long been awaited. We report here a genetic method to screen for PTP substrates which we have named the "yeast substrate-trapping system." This method is based on the yeast two-hybrid system with two essential modifications: the conditional expression of a PTK to tyrosine-phosphorylate the prey protein, and screening using a substrate-trap PTP mutant as bait. This method is probably applicable to all the PTPs, because it is based on PTP-substrate interaction in vivo, namely the substrate recognition of individual PTPs. Moreover, this method has the advantage that continuously interacting molecules for a PTP are also identified, at the same time, under PTK-noninductive conditions. The identification of physiological substrates will shed light on the physiological functions of individual PTPs.
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Affiliation(s)
- Masahide Fukada
- Division of Molecular Neurobiology, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji-cho, Okazaki 444-8787, Japan
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23
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Huang Z, Zhou B, Zhang ZY. Molecular Determinants of Substrate Recognition in Hematopoietic Protein-tyrosine Phosphatase. J Biol Chem 2004; 279:52150-9. [PMID: 15466470 DOI: 10.1074/jbc.m407820200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The extracellular signal-regulated protein kinase 2 (ERK2) plays a central role in cellular proliferation and differentiation. Full activation of ERK2 requires dual phosphorylation of Thr183 and Tyr185 in the activation loop. Tyr185 dephosphorylation by the hematopoietic protein-tyrosine phosphatase (HePTP) represents an important mechanism for down-regulating ERK2 activity. The bisphosphorylated ERK2 is a highly efficient substrate for HePTP with a kcat/Km of 2.6 x 10(6) m(-1) s(-1). In contrast, the kcat/Km values for the HePTP-catalyzed hydrolysis of Tyr(P) peptides are 3 orders of magnitude lower. To gain insight into the molecular basis for HePTP substrate specificity, we analyzed the effects of altering structural features unique to HePTP on the HePTP-catalyzed hydrolysis of p-nitrophenyl phosphate, Tyr(P) peptides, and its physiological substrate ERK2. Our results suggest that substrate specificity is conferred upon HePTP by both negative and positive selections. To avoid nonspecific tyrosine dephosphorylation, HePTP employs Thr106 in the substrate recognition loop as a key negative determinant to restrain its protein-tyrosine phosphatase activity. The extremely high efficiency and fidelity of ERK2 dephosphorylation by HePTP is achieved by a bipartite protein-protein interaction mechanism, in which docking interactions between the kinase interaction motif in HePTP and the common docking site in ERK2 promote the HePTP-catalyzed ERK2 dephosphorylation (approximately 20-fold increase in kcat/Km) by increasing the local substrate concentration, and second site interactions between the HePTP catalytic site and the ERK2 substrate-binding region enhance catalysis (approximately 20-fold increase in kcat/Km) by organizing the catalytic residues with respect to Tyr(P)185 for optimal phosphoryl transfer.
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Affiliation(s)
- Zhonghui Huang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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24
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Davis A, Kilner CA, Kee TP. Complexes containing the (R,R)-N,N′-bis(2-hydroxy-3-functionalised-benzylidene)-1,2-diaminocyclohexane ligand: synthesis and X-ray analyses of titanium chloro and oxo derivatives. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2004.01.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Wang J, Chan SL, Ramnarayan K. Structure-based prediction of free energy changes of binding of PTP1B inhibitors. J Comput Aided Mol Des 2004; 17:495-513. [PMID: 14703121 DOI: 10.1023/b:jcam.0000004602.70594.5f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The goals were (1) to understand the driving forces in the binding of small molecule inhibitors to the active site of PTP1B and (2) to develop a molecular mechanics-based empirical free energy function for compound potency prediction. A set of compounds with known activities was docked onto the active site. The related energy components and molecular surface areas were calculated. The bridging water molecules were identified and their contributions were considered. Linear relationships were explored between the above terms and the binding free energies of compounds derived based on experimental inhibition constants. We found that minimally three terms are required to give rise to a good correlation (0.86) with predictive power in five-group cross-validation test (q2 = 0.70). The dominant terms are the electrostatic energy and non-electrostatic energy stemming from the intra- and intermolecular interactions of solutes and from those of bridging water molecules in complexes.
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Affiliation(s)
- Jing Wang
- Structural Bioinformatics Inc., 10929 Technology Place, San Diego, CA 92127, USA.
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26
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Kumar S, Zhou B, Liang F, Wang WQ, Huang Z, Zhang ZY. Activity-based probes for protein tyrosine phosphatases. Proc Natl Acad Sci U S A 2004; 101:7943-8. [PMID: 15148367 PMCID: PMC419536 DOI: 10.1073/pnas.0402323101] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein tyrosine phosphatases (PTPs) are involved in the regulation of many aspects of cellular activity including proliferation, differentiation, metabolism, migration, and survival. Given the large number and complexity of PTPs in cell signaling, new strategies are needed for the integrated analysis of PTPs in the whole proteome. Unfortunately, the activities of many PTPs are tightly regulated by posttranslational mechanisms, limiting the utility of standard genomics and proteomics methods for functional characterization of these enzymes. To facilitate the global analysis of PTPs, we designed and synthesized two activity-based probes that consist of alpha-bromobenzylphosphonate as a PTP-specific trapping device and a linker that connects the trapping device with a biotin tag for visualization and purification. We showed that these probes are active site-directed irreversible inactivators of PTPs and form a covalent adduct with PTPs involving the active site Cys residue. Additionally, we demonstrated that the probes are extremely specific toward PTPs while remaining inert to other proteins, including the whole proteome from Escherichia coli. Consequently, these activity-based PTP probes can be used to profile PTP activity in complex proteomes. The ability to interrogate the entire PTP family on the basis of changes in their activity should greatly accelerate both the assignment of PTP function and the identification of potential therapeutic targets.
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Affiliation(s)
- Sanjai Kumar
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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27
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Zhang ZY. Mechanistic studies on protein tyrosine phosphatases. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 73:171-220. [PMID: 12882518 DOI: 10.1016/s0079-6603(03)01006-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The human genome encodes approximately 100 phosphatases that belong to the protein tyrosine phosphatase (PTP) superfamily. The hallmark for this superfamily is the active site sequence C(X)5R, also known as the PTP signature motif. The PTPs are key regulatory components in signal transduction pathways and the importance of PTPs in the control of cellular signaling is well established. Based on structure and substrate specificity, the PTP superfamily is divided into four distinct subfamilies: (1) pTyr-specific PTPs, (2) dual specificity phosphatases, (3) Cdc25 phosphatases, and (4) LMW PTPs. The PTPs have similar core structures made of a central parallel beta-sheet with flanking a-helices containing a beta-loop-alpha-loop that encompasses the PTP signature motif. Site-directed mutagenesis of conserved amino acids in the Yersinia PTP and several other phosphatases in the PTP superfamily combined with detailed kinetic and mechanistic analyses have revealed a common chemical mechanism for phosphate hydrolysis despite the differences in substrate specificity. This article reviews our current knowledge of the common features important for PTP catalysis, the nature of the enzymatic transition state, and the roles of essential residues in transition stabilization. Future mechanistic studies of PTPs will focus on the use of physiological substrates to determine the molecular basis of substrate recognition and regulation, which is essential for understanding the specific functional role of PTPs in cellular signaling.
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Affiliation(s)
- Zhong-Yin Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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28
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Wälchli S, Espanel X, Harrenga A, Rossi M, Cesareni G, Hooft van Huijsduijnen R. Probing protein-tyrosine phosphatase substrate specificity using a phosphotyrosine-containing phage library. J Biol Chem 2003; 279:311-8. [PMID: 14578355 DOI: 10.1074/jbc.m307617200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein tyrosine phosphatases (PTPs) play important, highly dynamic roles in signaling. Currently about 90 different PTP genes have been described. The enzymes are highly regulated at all levels of expression, and it is becoming increasingly clear that substrate specificity of the PTP catalytic domains proper contributes considerably to PTP functionality. To investigate PTP substrate selectivity, we have set up a procedure to generate phage libraries that presents randomized, phosphotyrosine-containing peptides. Phages that expressed suitable substrates were selected by immobilized, substrate-trapping GST-PTP fusion proteins. After multiple rounds of selection, positive clones were confirmed by SPOT analysis, dephosphorylation by wild-type enzyme, and Km determinations. We have identified distinct consensus substrate motifs for PTP1B, Sap-1, PTP-beta, SHP1, and SHP2. Our results confirm substrate specificity for individual PTPs at the peptide level. Such consensus sequences may be useful both for identifying potential PTP substrates and for the development of peptidomimetic inhibitors.
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Affiliation(s)
- Sébastien Wälchli
- Serono Pharmaceutical Research Institute, CH-1228 Geneva, Switzerland
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29
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Sun JP, Wu L, Fedorov AA, Almo SC, Zhang ZY. Crystal structure of the Yersinia protein-tyrosine phosphatase YopH complexed with a specific small molecule inhibitor. J Biol Chem 2003; 278:33392-9. [PMID: 12810712 DOI: 10.1074/jbc.m304693200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pathogenic bacteria Yersinia are causative agents in human diseases ranging from gastrointestinal syndromes to bubonic plague. There is increasing risk of misuse of infectious agents, such as Yersinia pestis, as weapons of terror as well as instruments of warfare for mass destruction. Because the phosphatase activity of the Yersinia protein tyrosine phosphatase, YopH, is essential for virulence in the Yersinia pathogen, potent and selective YopH inhibitors are expected to serve as novel anti-plague agents. We have identified a specific YopH small molecule inhibitor, p-nitrocatechol sulfate (pNCS), which exhibits a Ki value of 25 microM for YopH and displays a 13-60-fold selectivity in favor of YopH against a panel of mammalian PTPs. To facilitate the understanding of the underlying molecular basis for tight binding and specificity, we have determined the crystal structure of YopH in complex with pNCS at a 2.0-A resolution. The structural data are corroborated by results from kinetic analyses of the interactions of YopH and its site-directed mutants with pNCS. The results show that while the interactions of the sulfuryl moiety and the phenyl ring with the YopH active site contribute to pNCS binding affinity, additional interactions of the hydroxyl and nitro groups in pNCS with Asp-356, Gln-357, Arg-404, and Gln-446 are responsible for the increased potency and selectivity. In particular, we note that residues Arg-404, Glu-290, Asp-356, and a bound water (WAT185) participate in a unique H-bonding network with the hydroxyl group ortho to the sulfuryl moiety, which may be exploited to design more potent and specific YopH inhibitors.
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Affiliation(s)
- Jin-Peng Sun
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Romsicki Y, Scapin G, Beaulieu-Audy V, Patel S, Becker JW, Kennedy BP, Asante-Appiah E. Functional characterization and crystal structure of the C215D mutant of protein-tyrosine phosphatase-1B. J Biol Chem 2003; 278:29009-15. [PMID: 12748196 DOI: 10.1074/jbc.m303817200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have characterized the C215D active-site mutant of protein-tyrosine phosphatase-1B (PTP-1B) and solved the crystal structure of the catalytic domain of the apoenzyme to a resolution of 1.6 A. The mutant enzyme displayed maximal catalytic activity at pH approximately 4.5, which is significantly lower than the pH optimum of 6 for wild-type PTP-1B. Although both forms of the enzyme exhibited identical Km values for hydrolysis of p-nitrophenyl phosphate at pH 4.5 and 6, the kcat values of C215D were approximately 70- and approximately 7000-fold lower than those of wild-type PTP-1B, respectively. Arrhenius plots revealed that the mutant and wild-type enzymes displayed activation energies of 61 +/- 1 and 18 +/- 2 kJ/mol, respectively, at their pH optima. Unlike wild-type PTP-1B, C215D-mediated p-nitrophenyl phosphate hydrolysis was inactivated by 1,2-epoxy-3-(p-nitrophenoxy)propane, suggesting a direct involvement of Asp215 in catalysis. Increasing solvent microviscosity with sucrose (up to 40% (w/v)) caused a significant decrease in kcat/Km of the wild-type enzyme, but did not alter the catalytic efficiency of the mutant protein. Structurally, the apoenzyme was identical to wild-type PTP-1B, aside from the flexible WPD loop region, which was in both "open" and "closed" conformations. At physiological pH, the C215D mutant of PTP-1B should be an effective substrate-trapping mutant that can be used to identify cellular substrates of PTP-1B. In addition, because of its insensitivity to oxidation, this mutant may be used for screening fermentation broth and other natural products to identify inhibitors of PTP-1B.
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Affiliation(s)
- Yolanda Romsicki
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, Pointe-Claire, Dorval, Quebec H9R 4P8, Canada
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31
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Sun JP, Fedorov AA, Lee SY, Guo XL, Shen K, Lawrence DS, Almo SC, Zhang ZY. Crystal structure of PTP1B complexed with a potent and selective bidentate inhibitor. J Biol Chem 2003; 278:12406-14. [PMID: 12547827 DOI: 10.1074/jbc.m212491200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) has been implicated as an important regulator in several signaling pathways including those initiated by insulin and leptin. Potent and specific PTP1B inhibitors could serve as useful tools in elucidating the physiological functions of PTP1B and may constitute valuable therapeutics in the treatment of several human diseases. We have determined the crystal structure of PTP1B in complex with compound 2, the most potent and selective PTP1B inhibitor reported to date. The structure at 2.15-A resolution reveals that compound 2 simultaneously binds to the active site and a unique proximal noncatalytic site formed by Lys-41, Arg-47, and Asp-48. The structural data are further corroborated by results from kinetic analyses of the interactions of PTP1B and its site-directed mutants with compound 2 and several of its variants. Although many of the residues important for interactions between PTP1B and compound 2 are not unique to PTP1B, the combinations of all contact residues differ between PTP isozymes, which provide a structural basis for potent and selective PTP1B inhibition. Our data further suggest that potent, yet highly selective, PTP1B inhibitory agents can be acquired by targeting the area defined by residues Lys-41, Arg-47, and Asp-48, in addition to the previously identified second aryl phosphate-binding pocket.
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Affiliation(s)
- Jin-Peng Sun
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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32
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33
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Zhang ZY. Protein tyrosine phosphatases: structure and function, substrate specificity, and inhibitor development. Annu Rev Pharmacol Toxicol 2002; 42:209-34. [PMID: 11807171 DOI: 10.1146/annurev.pharmtox.42.083001.144616] [Citation(s) in RCA: 332] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Protein tyrosine phosphatases (PTPs) are signaling enzymes that control a diverse array of cellular processes. Malfunction of PTP activity is associated with a number of human disorders. Recent genetic and biochemical studies indicate that PTPs represent a novel platform for drug discovery. Detailed knowledge of PTP substrate specificity and the wealth of structural data on PTPs provide a solid foundation for rational PTP inhibitor design. This review summarizes a correlation of PTP structure and function from mutagenesis experiments. The molecular basis for PTP1B and MKP3 substrate recognition is discussed. A powerful strategy is presented for creating specific and high-affinity bidentate PTP inhibitors that simultaneously bind both the active site and a unique adjacent site. Finally, recent advances in the development of potent and selective inhibitors for PTP1B and Cdc25 are described.
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Affiliation(s)
- Zhong-Yin Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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34
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McCain DF, Catrina IE, Hengge AC, Zhang ZY. The catalytic mechanism of Cdc25A phosphatase. J Biol Chem 2002; 277:11190-200. [PMID: 11805096 DOI: 10.1074/jbc.m109636200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cdc25 phosphatases are dual specificity phosphatases that dephosphorylate and activate cyclin-dependent kinases (CDKs), thereby effecting the progression from one phase of the cell cycle to the next. Despite its central role in the cell cycle, relatively little is known about the catalytic mechanism of Cdc25. In order to provide insights into the catalytic mechanism of Cdc25, we have performed a detailed mechanistic analysis of the catalytic domain of human Cdc25A. Our kinetic isotope effect results, Bronsted analysis, and pH dependence studies employing a range of aryl phosphates clearly indicate a dissociative transition state for the Cdc25A reaction that does not involve a general acid for the hydrolysis of substrates with low leaving group pK(a) values (5.45-8.05). Interestingly, our Bronsted analysis and pH dependence studies reveal that Cdc25A employs a different mechanism for the hydrolysis of substrates with high leaving group pK(a) values (8.68-9.99) that appears to require the protonation of glutamic acid 431. Mutation of glutamic acid 431 into glutamine leads to a dramatic drop in the hydrolysis rate for the high leaving group pK(a) substrates and the disappearance of the basic limb of the pH rate profile for the substrate with a leaving group pK(a) of 8.05, indicating that glutamic acid 431 is essential for the efficient hydrolysis of substrates with high leaving group pK(a). We suggest that hydrolysis of the high leaving group pK(a) substrates proceeds through an unfavored but more catalytically active form of Cdc25A, and we propose several models illustrating this. Since the activity of Cdc25A toward small molecule substrates is several orders of magnitude lower than toward the physiological substrate, cyclin-CDK, we suggest that the cyclin-CDK is able to preferentially induce this more catalytically active form of Cdc25A for efficient phosphothreonine and phosphotyrosine dephosphorylation.
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Affiliation(s)
- Daniel F McCain
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, 10461, USA
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35
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Hill RJ, Zozulya S, Lu YL, Ward K, Gishizky M, Jallal B. The lymphoid protein tyrosine phosphatase Lyp interacts with the adaptor molecule Grb2 and functions as a negative regulator of T-cell activation. Exp Hematol 2002; 30:237-44. [PMID: 11882361 DOI: 10.1016/s0301-472x(01)00794-9] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Following activation of T cells, phosphorylation of tyrosine residues occurs through a complex signaling process involving protein tyrosine kinases, phosphatases, and a variety of adapter molecules including Grb2. We have attempted to identify new signaling molecules that are important for the activation response. METHODS Using a protein interaction screening protocol based on phage display, T-cell signaling components that associate with the adapter molecule, Grb2, the lymphoid-specific tyrosine phosphatase Lyp was identified. Using transcriptional reporter assays, the role of Lyp in T-cell activation was studied by overexpression of wild-type or catalytically inactive mutants of Lyp. RESULTS A GST fusion containing the C-terminal SH3 domain of Grb2 bound to the nucleotide exchange factor Sos or Grb2-associated binder 2 (Gab2). In contrast, the N-terminal SH3-containing fusion bound to the protein tyrosine phosphatase Lyp. Grb2 was co-immunoprecipitated with Lyp in 293T cells overexpressing both proteins. Using Northern blot analysis, Lyp was found to be expressed predominantly in hematopoietic tissue, including spleen, lymph node, thymus, peripheral blood leukocytes, bone marrow, and fetal liver. Two human T-cell lines, Jurkat and HuT78, expressed both Lyp mRNA and protein. Overexpression of wild-type Lyp or a catalytically inactive, substrate-trapping mutant (D195A) in Jurkat cells inhibited transcriptional activity initiated by anti-CD3 and anti-CD28 antibodies. In contrast, two other catalytically inactive mutants (R233M or C227S) had no effect. CONCLUSION These data demonstrate a novel interaction between the phosphatase Lyp and the adaptor Grb2 and are consistent with a negative regulatory role for Lyp in T-cell signaling.
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Affiliation(s)
- Ronald J Hill
- Research Department, Sugen, Inc., South San Francisco, CA 94080, USA.
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Shen K, Keng YF, Wu L, Guo XL, Lawrence DS, Zhang ZY. Acquisition of a specific and potent PTP1B inhibitor from a novel combinatorial library and screening procedure. J Biol Chem 2001; 276:47311-9. [PMID: 11584002 DOI: 10.1074/jbc.m106568200] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Protein-tyrosine phosphatases (PTPases) form a large family of enzymes that serve as key regulatory components in signal transduction pathways. Defective or inappropriate regulation of PTPase activity leads to aberrant tyrosine phosphorylation, which contributes to the development of many human diseases including cancers and diabetes. For example, recent gene knockout studies in mice identify PTP1B as a promising target for anti-diabetes/obesity drug discovery. Thus, there is intense interest in obtaining specific and potent PTPase inhibitors for biological studies and pharmacological development. However, given the highly conserved nature of the PTPase active site, it is unclear whether selectivity in PTPase inhibition can be achieved. We describe a combinatorial approach that is designed to target both the active site and a unique peripheral site in PTP1B. Compounds that can simultaneously associate with both sites are expected to exhibit enhanced affinity and specificity. We also describe a novel affinity-based high-throughput assay procedure that can be used for PTPase inhibitor screening. The combinatorial library/high-throughput screen protocols furnished a small molecule PTP1B inhibitor that is both potent (K(i) = 2.4 nm) and selective (little or no activity against a panel of phosphatases including Yersinia PTPase, SHP1, SHP2, LAR, HePTP, PTPalpha, CD45, VHR, MKP3, Cdc25A, Stp1, and PP2C). These results demonstrate that it is possible to acquire potent, yet highly selective inhibitors for individual members of the large PTPase family of enzymes.
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Affiliation(s)
- K Shen
- Department of Biochemistry, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
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37
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Andersen JN, Mortensen OH, Peters GH, Drake PG, Iversen LF, Olsen OH, Jansen PG, Andersen HS, Tonks NK, Møller NP. Structural and evolutionary relationships among protein tyrosine phosphatase domains. Mol Cell Biol 2001; 21:7117-36. [PMID: 11585896 PMCID: PMC99888 DOI: 10.1128/mcb.21.21.7117-7136.2001] [Citation(s) in RCA: 526] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- J N Andersen
- Signal Transduction, Novo Nordisk, Måløv, Denmark
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38
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Leavitt S, Freire E. Direct measurement of protein binding energetics by isothermal titration calorimetry. Curr Opin Struct Biol 2001; 11:560-6. [PMID: 11785756 DOI: 10.1016/s0959-440x(00)00248-7] [Citation(s) in RCA: 471] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Of all the techniques that are currently available to measure binding, isothermal titration calorimetry is the only one capable of measuring not only the magnitude of the binding affinity but also the magnitude of the two thermodynamic terms that define the binding affinity: the enthalpy (AH) and entropy (AS) changes. Recent advances in instrumentation have facilitated the development of experimental designs that permit the direct measurement of arbitrarily high binding affinities, the coupling of binding to protonation/deprotonation processes and the analysis of binding thermodynamics in terms of structural parameters. Because isothermal titration calorimetry has the capability to measure different energetic contributions to the binding affinity, it provides a unique bridge between computational and experimental analysis. As such, it is increasingly becoming an essential tool in molecular design.
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Affiliation(s)
- S Leavitt
- Department of Biology and Biocalorimetry Center, The Johns Hopkins University, Baltimore, MD 21218, USA
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39
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Scapin G, Patel S, Patel V, Kennedy B, Asante-Appiah E. The structure of apo protein-tyrosine phosphatase 1B C215S mutant: more than just an S --> O change. Protein Sci 2001; 10:1596-605. [PMID: 11468356 PMCID: PMC2374080 DOI: 10.1110/ps.11001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Protein-tyrosine phosphatases catalyze the hydrolysis of phosphate monoesters via a two-step mechanism involving a covalent phospho-enzyme intermediate. Biochemical and site-directed mutagenesis experiments show that the invariant Cys residue present in the PTPase signature motif (H/V)CX(5)R(S/T) (i.e., C215 in PTP1B) is absolutely required for activity. Mutation of the invariant Cys to Ser results in a catalytically inactive enzyme, which still is capable of binding substrates and inhibitors. Although it often is assumed that substrate-trapping mutants such as the C215S retain, in solution, the structural and binding properties of wild-type PTPases, significant differences have been found in the few studies that have addressed this issue, suggesting that the mutation may lead to structural/conformational alterations in or near the PTP1B binding site. Several crystal structures of apo-WT PTP1B, and of WT- and C215S-mutant PTP1B in complex with different ligands are available, but no structure of the apo-PTP1B C215S has ever been reported. In all previously reported structures, residues of the PTPase signature motif have an identical conformation, while residues of the WPD loop (a surface loop which includes the catalytic Asp) assume a different conformation in the presence or absence of ligand. These observations led to the hypothesis that the different spectroscopic and thermodynamic properties of the mutant protein may be the result of a different conformation for the WPD loop. We report here the structure of the apo-PTP1B C215S mutant, which reveals that, while the WPD loop is in the open conformation observed in the apo WT enzyme crystal structure, the residues of the PTPases signature motif are in a dramatically different conformation. These results provide a structural basis for the differences in spectroscopic properties and thermodynamic parameters in inhibitor binding observed for the wild-type and mutant enzymes.
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Affiliation(s)
- G Scapin
- Department of Endocrinology and Chemical Biology, Merck Research Laboratories, Rahway, NJ 07065, USA.
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40
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Asante-Appiah E, Ball K, Bateman K, Skorey K, Friesen R, Desponts C, Payette P, Bayly C, Zamboni R, Scapin G, Ramachandran C, Kennedy BP. The YRD Motif Is a Major Determinant of Substrate and Inhibitor Specificity in T-cell Protein-tyrosine Phosphatase. J Biol Chem 2001; 276:26036-43. [PMID: 11352902 DOI: 10.1074/jbc.m011697200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied T-cell protein-tyrosine phosphatase (TCPTP) as a model phosphatase in an attempt to unravel amino acid residues that may influence the design of specific inhibitors. Residues 48--50, termed the YRD motif, a region that is found in protein-tyrosine phosphatases, but absent in dual-specificity phosphatases was targeted. YRD derivatives of TCPTP were characterized by steady-state kinetics and by inhibition studies with BzN-EJJ-amide, a potent inhibitor of TCPTP. Substitution of Asp(50) to alanine or Arg(49) to lysine, methionine, or alanine significantly affected substrate hydrolysis and led to a substantial decrease in affinity for BzN-EJJ-amide. The influence of residue 49 on substrate/inhibitor selectivity was further investigated by comparing subsite amino acid preferences of TCPTP and its R49K derivative by affinity selection coupled with mass spectrometry. The greatest effect on selectivity was observed on the residue that precedes the phosphorylated tyrosine. Unlike wild-type TCPTP, the R49K derivative preferred tyrosine to aspartic or glutamic acid. BzN-EJJ-amide which retains the preferred specificity requirements of TCPTP and PTP1B was equipotent on both enzymes but greater than 30-fold selective over other phosphatases. These results suggest that Arg(49) and Asp(50) may be targeted for the design of potent and selective inhibitors of TCPTP and PTP1B.
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Affiliation(s)
- E Asante-Appiah
- Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Pointe-Claire-Dorval H9R 4P8, Canada.
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41
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Traverso EE, Baskerville C, Liu Y, Shou W, James P, Deshaies RJ, Charbonneau H. Characterization of the Net1 cell cycle-dependent regulator of the Cdc14 phosphatase from budding yeast. J Biol Chem 2001; 276:21924-31. [PMID: 11274204 DOI: 10.1074/jbc.m011689200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, the multifunctional protein Net1 is implicated in regulating the cell cycle function of the Cdc14 protein phosphatase. Genetic and cell biological data suggest that during interphase and early mitosis Net1 holds Cdc14 within the nucleolus where its activity is suppressed. Upon its transient release from Net1 at late anaphase, active Cdc14 promotes exit from mitosis by dephosphorylating targets in the nucleus and cytoplasm. In this paper we present evidence supporting the proposed role of Net1 in regulating Cdc14 and exit from mitosis. We show that the NH(2)-terminal fragment Net1(1-600) directly binds Cdc14 in vitro and is a highly specific competitive inhibitor of its activity (K(i) = 3 nm) with five different substrates including the physiologic targets Swi5 and Sic1. An analysis of truncation mutants indicates that the Cdc14 binding site is located within a segment of Net1 containing residues 1-341. We propose that Net1 inhibits by occluding the active site of Cdc14 because it acts as a competitive inhibitor, binds to a site located within the catalytic domain (residues 1-374), binds with reduced affinity to a Cdc14 C283S mutant in which an active site Cys is replaced, and is displaced by tungstate, a transition state analog known to bind in the catalytic site of protein-tyrosine phosphatases.
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Affiliation(s)
- E E Traverso
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
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