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Gangopadhyay K, Roy S, Sen Gupta S, Chandradasan A, Chowdhury S, Das R. Regulating the discriminatory response to antigen by T-cell receptor. Biosci Rep 2022; 42:BSR20212012. [PMID: 35260878 PMCID: PMC8965820 DOI: 10.1042/bsr20212012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 11/17/2022] Open
Abstract
The cell-mediated immune response constitutes a robust host defense mechanism to eliminate pathogens and oncogenic cells. T cells play a central role in such a defense mechanism and creating memories to prevent any potential infection. T cell recognizes foreign antigen by its surface receptors when presented through antigen-presenting cells (APCs) and calibrates its cellular response by a network of intracellular signaling events. Activation of T-cell receptor (TCR) leads to changes in gene expression and metabolic networks regulating cell development, proliferation, and migration. TCR does not possess any catalytic activity, and the signaling initiates with the colocalization of several enzymes and scaffold proteins. Deregulation of T cell signaling is often linked to autoimmune disorders like severe combined immunodeficiency (SCID), rheumatoid arthritis, and multiple sclerosis. The TCR remarkably distinguishes the minor difference between self and non-self antigen through a kinetic proofreading mechanism. The output of TCR signaling is determined by the half-life of the receptor antigen complex and the time taken to recruit and activate the downstream enzymes. A longer half-life of a non-self antigen receptor complex could initiate downstream signaling by activating associated enzymes. Whereas, the short-lived, self-peptide receptor complex disassembles before the downstream enzymes are activated. Activation of TCR rewires the cellular metabolic response to aerobic glycolysis from oxidative phosphorylation. How does the early event in the TCR signaling cross-talk with the cellular metabolism is an open question. In this review, we have discussed the recent developments in understanding the regulation of TCR signaling, and then we reviewed the emerging role of metabolism in regulating T cell function.
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Affiliation(s)
- Kaustav Gangopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
| | - Swarnendu Roy
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
| | - Soumee Sen Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
| | - Athira C. Chandradasan
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
| | - Subhankar Chowdhury
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
| | - Rahul Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
- Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur campus, Mohanpur 741246, India
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An allosteric hot spot in the tandem-SH2 domain of ZAP-70 regulates T-cell signaling. Biochem J 2020; 477:1287-1308. [PMID: 32203568 DOI: 10.1042/bcj20190879] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/18/2020] [Accepted: 03/23/2020] [Indexed: 12/28/2022]
Abstract
T-cell receptor (TCR) signaling is initiated by recruiting ZAP-70 to the cytosolic part of TCR. ZAP-70, a non-receptor tyrosine kinase, is composed of an N-terminal tandem SH2 (tSH2) domain connected to the C-terminal kinase domain. The ZAP-70 is recruited to the membrane through binding of tSH2 domain and the doubly phosphorylated ITAM motifs of CD3 chains in the TCR complex. Our results show that the tSH2 domain undergoes a biphasic structural transition while binding to the doubly phosphorylated ITAM-ζ1 peptide. The C-terminal SH2 domain binds first to the phosphotyrosine residue of ITAM peptide to form an encounter complex leading to subsequent binding of second phosphotyrosine residue to the N-SH2 domain. We decipher a network of noncovalent interactions that allosterically couple the two SH2 domains during binding to doubly phosphorylated ITAMs. Mutation in the allosteric network residues, for example, W165C, uncouples the formation of encounter complex to the subsequent ITAM binding thus explaining the altered recruitment of ZAP-70 to the plasma membrane causing autoimmune arthritis in mice. The proposed mechanism of allosteric coupling is unique to ZAP-70, which is fundamentally different from Syk, a close homolog of ZAP-70 expressed in B-cells.
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3
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Syk Inhibitors: New Computational Insights into Their Intraerythrocytic Action in Plasmodium falciparum Malaria. Int J Mol Sci 2020; 21:ijms21197009. [PMID: 32977621 PMCID: PMC7582821 DOI: 10.3390/ijms21197009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/12/2020] [Accepted: 09/18/2020] [Indexed: 12/23/2022] Open
Abstract
Resistance to antimalarial drugs has spread rapidly over the past few decades. The WHO recommends artemisinin-based combination therapies for the treatment of uncomplicated malaria, but unfortunately these approaches are losing their efficacy in large areas of Southeast Asia. In 2016, artemisinin resistance was confirmed in 5 countries of the Greater Mekong subregion. We focused our study on Syk inhibitors as antimalarial drugs. The Syk protein is present in human erythrocytes, and the membrane of protein band 3 is its major target following activation by oxidant stress. Tyr phosphorylation of band 3 occurs during P. falciparum growth, leading to the release of microparticles containing hemicromes and structural weakening of the host cell membrane, simplifying merozoite reinfection. Syk inhibitors block these events by interacting with the Syk protein’s catalytic site. We performed in vitro proteomics and in silico studies and compared the results. In vitro studies were based on treatment of the parasite’s cellular cultures with different concentrations of Syk inhibitors, while proteomics studies were focused on the Tyr phosphorylation of band 3 by Syk protein with the same concentrations of drugs. In silico studies were based on different molecular modeling approaches in order to analyze and optimize the ligand–protein interactions and obtain the highest efficacy in vitro. In the presence of Syk inhibitors, we observed a marked decrease of band 3 Tyr phosphorylation according to the increase of the drug’s concentration. Our studies could be useful for the structural optimization of these compounds and for the design of novel Syk inhibitors in the future.
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4
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Dube N, Marzinek JK, Glen RC, Bond PJ. The structural basis for membrane assembly of immunoreceptor signalling complexes. J Mol Model 2019; 25:277. [PMID: 31456056 DOI: 10.1007/s00894-019-4165-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/15/2019] [Indexed: 11/25/2022]
Abstract
Immunoreceptors are TM complexes that consist of separate ligand-binding and signal-transducing modules. Mounting evidence suggests that interactions with the local environment may influence the architecture of these TM domains, which assemble via crucial sets of conserved ionisable residues, and also control the peripheral association of immunoreceptor tyrosine-based activation motifs (ITAMs) whose phosphorylation triggers cytoplasmic signalling cascades. We now report a molecular dynamics (MD) simulation study of the archetypal T cell receptor (TCR) and its cluster of differentiation 3 (CD3) signalling partners, along with the analogous DNAX-activation protein of 12 kDa (DAP12)/natural killer group 2C (NKG2C) complex. Based on > 15 μs of explicitly solvated, atomic-resolution sampling, we explore molecular aspects of immunoreceptor complex stability in different functionally relevant states. A novel alchemical approach is used to simulate the cytoplasmic CD3ε tail at different depths within lipid bilayer models, revealing that the conformation and cytoplasmic exposure of ITAMs are highly sensitive to local enrichment by different lipid species and to phosphorylation. Furthermore, simulations of the TCR and DAP12 TM domains in various states of oligomerisation suggest that, during the early stages of assembly, stable membrane insertion is facilitated by the interfacial lipid/solvent environment and/or partial ionisation of charged residues. Collectively, our results indicate that the architecture and mechanisms of signal transduction in immunoreceptor complexes are tightly regulated by interactions with the microenvironment.
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Affiliation(s)
- Namita Dube
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Tata Institute of Fundamental Research, 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, 500107, India
| | - Jan K Marzinek
- Bioinformatics Institute (A*STAR), 30 Biopolis Str., #07-01 Matrix, Singapore, 138671, Singapore
| | - Robert C Glen
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Division of Integrative Systems Medicine and Digestive Diseases, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Peter J Bond
- Bioinformatics Institute (A*STAR), 30 Biopolis Str., #07-01 Matrix, Singapore, 138671, Singapore.
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
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5
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Mansueto MS, Reens A, Rakhilina L, Chi A, Pan BS, Miller JR. A reevaluation of the spleen tyrosine kinase (SYK) activation mechanism. J Biol Chem 2019; 294:7658-7668. [PMID: 30923129 DOI: 10.1074/jbc.ra119.008045] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/25/2019] [Indexed: 11/06/2022] Open
Abstract
Spleen tyrosine kinase (SYK) is a signaling node in many immune pathways and comprises two tandem Src homology (SH) 2 domains, an SH2-kinase linker, and a C-terminal tyrosine kinase domain. Two prevalent models of SYK activation exist. The "OR-gate" model contends that SYK can be fully activated by phosphorylation or binding of its SH2 domains to a dual-phosphorylated immune-receptor tyrosine-based activation motif (ppITAM). An alternative model proposes that SYK activation requires ppITAM binding and phosphorylation of the SH2-kinase linker by a SRC family kinase such as LYN proto-oncogene, SRC family tyrosine kinase (LYN). To evaluate these two models, we generated directly comparable unphosphorylated (upSYK) and phosphorylated (pSYK) proteins with or without an N-terminal glutathione S-transferase (GST) tag, resulting in monomeric or obligatory dimeric SYK, respectively. We assessed the ability of a ppITAM peptide and LYN to activate these SYK proteins. The ppITAM peptide strongly activated GST-SYK but was less effective in activating upSYK untagged with GST. LYN alone activated untagged upSYK to a greater extent than did ppITAM, and inclusion of both proteins rapidly and fully activated upSYK. Using immunoblot and phosphoproteomic approaches, we correlated the kinetics and order of site-specific SYK phosphorylation. Our results are consistent with the alternative model, indicating that ppITAM binding primes SYK for rapid LYN-mediated phosphorylation of Tyr-352 and then Tyr-348 of the SH2-kinase linker, which facilitates activation loop phosphorylation and full SYK activation. This gradual activation mechanism may also explain how SYK maintains ligand-independent tonic signaling, important for B-cell development and survival.
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Affiliation(s)
| | | | | | - An Chi
- Chemical Biology, Merck & Co., Inc., Boston, Massachusetts 02115
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Ball KA, Johnson JR, Lewinski MK, Guatelli J, Verschueren E, Krogan NJ, Jacobson MP. Non-degradative Ubiquitination of Protein Kinases. PLoS Comput Biol 2016; 12:e1004898. [PMID: 27253329 PMCID: PMC4890936 DOI: 10.1371/journal.pcbi.1004898] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/02/2016] [Indexed: 12/22/2022] Open
Abstract
Growing evidence supports other regulatory roles for protein ubiquitination in addition to serving as a tag for proteasomal degradation. In contrast to other common post-translational modifications, such as phosphorylation, little is known about how non-degradative ubiquitination modulates protein structure, dynamics, and function. Due to the wealth of knowledge concerning protein kinase structure and regulation, we examined kinase ubiquitination using ubiquitin remnant immunoaffinity enrichment and quantitative mass spectrometry to identify ubiquitinated kinases and the sites of ubiquitination in Jurkat and HEK293 cells. We find that, unlike phosphorylation, ubiquitination most commonly occurs in structured domains, and on the kinase domain, ubiquitination is concentrated in regions known to be important for regulating activity. We hypothesized that ubiquitination, like other post-translational modifications, may alter the conformational equilibrium of the modified protein. We chose one human kinase, ZAP-70, to simulate using molecular dynamics with and without a monoubiquitin modification. In Jurkat cells, ZAP-70 is ubiquitinated at several sites that are not sensitive to proteasome inhibition and thus may have other regulatory roles. Our simulations show that ubiquitination influences the conformational ensemble of ZAP-70 in a site-dependent manner. When monoubiquitinated at K377, near the C-helix, the active conformation of the ZAP-70 C-helix is disrupted. In contrast, when monoubiquitinated at K476, near the kinase hinge region, an active-like ZAP-70 C-helix conformation is stabilized. These results lead to testable hypotheses that ubiquitination directly modulates kinase activity, and that ubiquitination is likely to alter structure, dynamics, and function in other protein classes as well. Attachment of ubiquitin to another protein is typically used to mark the protein for degradation by the proteasome. However, recent studies show that many proteins are tagged with ubiquitin and not degraded. We hypothesized that ubiquitin can regulate the protein it is attached to by changing its structure and dynamics. We performed proteomics experiments to identify all of the kinase proteins tagged by ubiquitin in a human cell line as well as the site of ubiquitination. We found that kinases are often ubiquitinated in structured regions important for regulation and activity. We then performed molecular dynamics simulations of one kinase, ZAP-70, to see if a ubiquitin tag could affect the kinase structure. We found that ubiquitin does affect the structure of ZAP-70, and the effect depends on where the ubiquitin is attached. At K377, ubiquitin changes the ZAP-70 structure to resemble the inactive state, while ubiquitin attached at K476, on the other side of the protein, has the opposite effect. These simulations indicate that ubiquitin, like other post-translational modifications, may alter the structure and dynamics of proteins in ways that impact activity and function.
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Affiliation(s)
- K. Aurelia Ball
- Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California, United States of America
| | - Jeffrey R. Johnson
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
| | - Mary K. Lewinski
- Division of Infectious Diseases, University of California at San Diego School of Medicine, La Jolla, California, United States of America
| | - John Guatelli
- Division of Infectious Diseases, University of California at San Diego School of Medicine, La Jolla, California, United States of America
| | - Erik Verschueren
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
| | - Nevan J. Krogan
- Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States of America
- * E-mail: (NJK); (MPJ)
| | - Matthew P. Jacobson
- Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California, United States of America
- * E-mail: (NJK); (MPJ)
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7
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The Structural Basis for Activation and Inhibition of ZAP-70 Kinase Domain. PLoS Comput Biol 2015; 11:e1004560. [PMID: 26473606 PMCID: PMC4608720 DOI: 10.1371/journal.pcbi.1004560] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/15/2015] [Indexed: 11/29/2022] Open
Abstract
ZAP–70 (Zeta-chain-associated protein kinase 70) is a tyrosine kinase that interacts directly with the activated T-cell receptor to transduce downstream signals, and is hence a major player in the regulation of the adaptive immune response. Dysfunction of ZAP–70 causes selective T cell deficiency that in turn results in persistent infections. ZAP–70 is activated by a variety of signals including phosphorylation of the kinase domain (KD), and binding of its regulatory tandem Src homology 2 (SH2) domains to the T cell receptor. The present study investigates molecular mechanisms of activation and inhibition of ZAP–70 via atomically detailed molecular dynamics simulation approaches. We report microsecond timescale simulations of five distinct states of the ZAP–70 KD, comprising apo, inhibited and three phosphorylated variants. Extensive analysis of local flexibility and correlated motions reveal crucial transitions between the states, thus elucidating crucial steps in the activation mechanism of the ZAP–70 KD. Furthermore, we rationalize previously observed staurosporine-bound crystal structures, suggesting that whilst the KD superficially resembles an “active-like” conformation, the inhibitor modulates the underlying protein dynamics and restricts it in a compact, rigid state inaccessible to ligands or cofactors. Finally, our analysis reveals a novel, potentially druggable pocket in close proximity to the activation loop of the kinase, and we subsequently use its structure in fragment-based virtual screening to develop a pharmacophore model. The pocket is distinct from classical type I or type II kinase pockets, and its discovery offers promise in future design of specific kinase inhibitors, whilst mutations in residues associated with this pocket are implicated in immunodeficiency in humans. ZAP–70 is a key protein kinase in the adaptive immune system. It is essential for development and function of T cells and natural killer cells, and associated mutations can lead to conditions such as severe combined immunodeficiency (SCID). Here, simulations of the ZAP–70 kinase domain are used to study its dynamics in response to different mechanistic signals. We identify crucial motions over microsecond timescales, which help to rationalize in atomic detail previous structural and experimental data regarding its biological regulation. We subsequently propose a scheme for the phosphorylation-dependent activation cascade of ZAP–70, and for its ligand-dependent inhibition. Finally, we characterize a novel cryptic pocket adjacent to the active site and activation loop, which is distinct from classical type I or type II kinase sites. The pocket is in close proximity to several residues whose mutations cause SCID in humans, and its identification offers promise in future drug design efforts.
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8
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Damle NP, Mohanty D. Mechanism of Autophosphorylation of Mycobacterial PknB Explored by Molecular Dynamics Simulations. Biochemistry 2014; 53:4715-26. [DOI: 10.1021/bi500245v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Nikhil P. Damle
- Bioinformatics
Center, National Institute of Immunology, Aruna Asaf Ali Marg, New
Delhi 110067, India
| | - Debasisa Mohanty
- Bioinformatics
Center, National Institute of Immunology, Aruna Asaf Ali Marg, New
Delhi 110067, India
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9
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Van Roey K, Uyar B, Weatheritt RJ, Dinkel H, Seiler M, Budd A, Gibson TJ, Davey NE. Short Linear Motifs: Ubiquitous and Functionally Diverse Protein Interaction Modules Directing Cell Regulation. Chem Rev 2014; 114:6733-78. [DOI: 10.1021/cr400585q] [Citation(s) in RCA: 293] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kim Van Roey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Robert J. Weatheritt
- MRC
Laboratory of Molecular Biology (LMB), Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
| | - Holger Dinkel
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Markus Seiler
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Aidan Budd
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J. Gibson
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Norman E. Davey
- Structural
and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Department
of Physiology, University of California, San Francisco, San Francisco, California 94143, United States
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10
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Paramo T, East A, Garzón D, Ulmschneider MB, Bond PJ. Efficient Characterization of Protein Cavities within Molecular Simulation Trajectories: trj_cavity. J Chem Theory Comput 2014; 10:2151-64. [DOI: 10.1021/ct401098b] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Teresa Paramo
- Unilever
Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Alexandra East
- Unilever
Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Diana Garzón
- Unilever
Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Martin B. Ulmschneider
- Department
of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Peter J. Bond
- Unilever
Centre for Molecular Science Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Bioinformatics Institute (A*STAR), 30
Biopolis Str, #07-01 Matrix, Singapore 138671
- Department
of Biological Sciences, National University of Singapore, 14 Science
Drive 4, 117543 Singapore
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11
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Corbi-Verge C, Marinelli F, Zafra-Ruano A, Ruiz-Sanz J, Luque I, Faraldo-Gómez JD. Two-state dynamics of the SH3-SH2 tandem of Abl kinase and the allosteric role of the N-cap. Proc Natl Acad Sci U S A 2013; 110:E3372-80. [PMID: 23959873 PMCID: PMC3767523 DOI: 10.1073/pnas.1303966110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The regulation and localization of signaling enzymes is often mediated by accessory modular domains, which frequently function in tandems. The ability of these tandems to adopt multiple conformations is as important for proper regulation as the individual domain specificity. A paradigmatic example is Abl, a ubiquitous tyrosine kinase of significant pharmacological interest. SH3 and SH2 domains inhibit Abl by assembling onto the catalytic domain, allosterically clamping it in an inactive state. We investigate the dynamics of this SH3-SH2 tandem, using microsecond all-atom simulations and differential scanning calorimetry. Our results indicate that the Abl tandem is a two-state switch, alternating between the conformation observed in the structure of the autoinhibited enzyme and another configuration that is consistent with existing scattering data for an activated form. Intriguingly, we find that the latter is the most probable when the tandem is disengaged from the catalytic domain. Nevertheless, an amino acid stretch preceding the SH3 domain, the so-called N-cap, reshapes the free-energy landscape of the tandem and favors the interaction of this domain with the SH2-kinase linker, an intermediate step necessary for assembly of the autoinhibited complex. This allosteric effect arises from interactions between N-cap and the SH2 domain and SH3-SH2 connector, which involve a phosphorylation site. We also show that the SH3-SH2 connector plays a determinant role in the assembly equilibrium of Abl, because mutations thereof hinder the engagement of the SH2-kinase linker. These results provide a thermodynamic rationale for the involvement of N-cap and SH3-SH2 connector in Abl regulation and expand our understanding of the principles of modular domain organization.
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Affiliation(s)
- Carles Corbi-Verge
- Department of Physical Chemistry and Institute of Biotechnology, University of Granada, 18071 Granada, Spain; and
| | - Fabrizio Marinelli
- Theoretical Molecular Biophysics Group, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Ana Zafra-Ruano
- Department of Physical Chemistry and Institute of Biotechnology, University of Granada, 18071 Granada, Spain; and
| | - Javier Ruiz-Sanz
- Department of Physical Chemistry and Institute of Biotechnology, University of Granada, 18071 Granada, Spain; and
| | - Irene Luque
- Department of Physical Chemistry and Institute of Biotechnology, University of Granada, 18071 Granada, Spain; and
| | - José D. Faraldo-Gómez
- Theoretical Molecular Biophysics Group, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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12
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Tomasio SM, Harding HP, Ron D, Cross BCS, Bond PJ. Selective inhibition of the unfolded protein response: targeting catalytic sites for Schiff base modification. MOLECULAR BIOSYSTEMS 2013; 9:2408-16. [DOI: 10.1039/c3mb70234k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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13
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Grädler U, Schwarz D, Dresing V, Musil D, Bomke J, Frech M, Greiner H, Jäkel S, Rysiok T, Müller-Pompalla D, Wegener A. Structural and biophysical characterization of the Syk activation switch. J Mol Biol 2012; 425:309-33. [PMID: 23154170 DOI: 10.1016/j.jmb.2012.11.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 11/05/2012] [Accepted: 11/06/2012] [Indexed: 11/28/2022]
Abstract
Syk is an essential non-receptor tyrosine kinase in intracellular immunological signaling, and the control of Syk kinase function is considered as a valuable target for pharmacological intervention in autoimmune or inflammation diseases. Upon immune receptor stimulation, the kinase activity of Syk is regulated by binding of phosphorylated immune receptor tyrosine-based activating motifs (pITAMs) to the N-terminal tandem Src homology 2 (tSH2) domain and by autophosphorylation with consequences for the molecular structure of the Syk protein. Here, we present the first crystal structures of full-length Syk (fl-Syk) as wild type and as Y348F,Y352F mutant forms in complex with AMP-PNP revealing an autoinhibited conformation. The comparison with the crystal structure of the truncated Syk kinase domain in complex with AMP-PNP taken together with ligand binding studies by surface plasmon resonance (SPR) suggests conformational differences in the ATP sites of autoinhibited and activated Syk forms. This hypothesis was corroborated by studying the thermodynamic and kinetic interaction of three published Syk inhibitors with isothermal titration calorimetry and SPR, respectively. We further demonstrate the modulation of inhibitor binding affinities in the presence of pITAM and discuss the observed differences of thermodynamic and kinetic signatures. The functional relevance of pITAM binding to fl-Syk was confirmed by a strong stimulation of in vitro autophosphorylation. A structural feedback mechanism on the kinase domain upon pITAM binding to the tSH2 domain is discussed in analogy of the related family kinase ZAP-70 (Zeta-chain-associated protein kinase 70). Surprisingly, we observed distinct conformations of the tSH2 domain and the activation switch including Tyr348 and Tyr352 in the interdomain linker of Syk in comparison to ZAP-70.
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Affiliation(s)
- Ulrich Grädler
- Merck KGaA, Merck Serono Research, Small Molecule Platform/MIB, Frankfurter Str. 250, 64293 Darmstadt, Germany.
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14
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Koutsoukas A, Simms B, Kirchmair J, Bond PJ, Whitmore AV, Zimmer S, Young MP, Jenkins JL, Glick M, Glen RC, Bender A. From in silico target prediction to multi-target drug design: current databases, methods and applications. J Proteomics 2011; 74:2554-74. [PMID: 21621023 DOI: 10.1016/j.jprot.2011.05.011] [Citation(s) in RCA: 186] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 04/10/2011] [Accepted: 05/06/2011] [Indexed: 01/31/2023]
Abstract
Given the tremendous growth of bioactivity databases, the use of computational tools to predict protein targets of small molecules has been gaining importance in recent years. Applications span a wide range, from the 'designed polypharmacology' of compounds to mode-of-action analysis. In this review, we firstly survey databases that can be used for ligand-based target prediction and which have grown tremendously in size in the past. We furthermore outline methods for target prediction that exist, both based on the knowledge of bioactivities from the ligand side and methods that can be applied in situations when a protein structure is known. Applications of successful in silico target identification attempts are discussed in detail, which were based partly or in whole on computational target predictions in the first instance. This includes the authors' own experience using target prediction tools, in this case considering phenotypic antibacterial screens and the analysis of high-throughput screening data. Finally, we will conclude with the prospective application of databases to not only predict, retrospectively, the protein targets of a small molecule, but also how to design ligands with desired polypharmacology in a prospective manner.
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Affiliation(s)
- Alexios Koutsoukas
- Unilever Centre for Molecular Sciences Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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