1
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Jin H, Liu D, Ni Y, Wang H, Long D. Quantitative Ensemble Interpretation of Membrane Paramagnetic Relaxation Enhancement (mPRE) for Studying Membrane-Associated Intrinsically Disordered Proteins. J Am Chem Soc 2024; 146:791-800. [PMID: 38146836 DOI: 10.1021/jacs.3c10847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
An understanding of the functional role played by a membrane-associated intrinsically disordered protein (IDP) requires characterization of its heterogeneous conformations as well as its poses relative to the membranes, which is of great interest but technically challenging. Here, we explore the membrane paramagnetic relaxation enhancement (mPRE) for constructing ensembles of IDPs that dynamically associate with membrane mimetics incorporating spin-labeled lipids. To accurately interpret the mPRE Γ2 rates, both the dynamics of IDPs and spin probe molecules are taken into account, with the latter described by a weighted three-dimensional (3D) grid model built based on all-atom simulations. The IDP internal conformations, orientations, and immersion depths in lipid bilayers are comprehensively optimized in the Γ2-based ensemble modeling. Our approach is tested and validated on the example of POPG bicelle-bound disordered cytoplasmic domain of CD3ε (CD3εCD), a component of the T-cell receptor (TCR) complex. The mPRE-derived CD3εCD ensemble provides new insights into the IDP-membrane fuzzy association, in particular for the tyrosine-based signaling motif that plays a critical role in TCR signaling. The comparative analysis of the ensembles for wild-type CD3εCD and mutants that mimic the mono- and dual-phosphorylation effects suggests a delicate membrane regulatory mechanism for activation and inhibition of the TCR activity.
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Affiliation(s)
- Hong Jin
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dan Liu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yu Ni
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Hui Wang
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dong Long
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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2
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Rollins ZA, Faller R, George SC. A dynamic biomimetic model of the membrane-bound CD4-CD3-TCR complex during pMHC disengagement. Biophys J 2023; 122:3133-3145. [PMID: 37381600 PMCID: PMC10432225 DOI: 10.1016/j.bpj.2023.06.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/19/2023] [Accepted: 06/23/2023] [Indexed: 06/30/2023] Open
Abstract
The coordinated (dis)engagement of the membrane-bound T cell receptor (TCR)-CD3-CD4 complex from the peptide-major histocompatibility complex (pMHC) is fundamental to TCR signal transduction and T cell effector function. As such, an atomic-scale understanding would not only enhance our basic understanding of the adaptive immune response but would also accelerate the rational design of TCRs for immunotherapy. In this study, we explore the impact of the CD4 coreceptor on the TCR-pMHC (dis)engagement by constructing a molecular-level biomimetic model of the CD3-TCR-pMHC and CD4-CD3-TCR-pMHC complexes within a lipid bilayer. After allowing the system complexes to equilibrate (engage), we use steered molecular dynamics to dissociate (disengage) the pMHC. We find that 1) the CD4 confines the pMHC closer to the T cell by 1.8 nm at equilibrium; 2) CD4 confinement shifts the TCR along the MHC binding groove engaging a different set of amino acids and enhancing the TCR-pMHC bond lifetime; 3) the CD4 translocates under load increasing the interaction strength between the CD4-pMHC, CD4-TCR, and CD4-CD3; and 4) upon dissociation, the CD3-TCR complex undergoes structural oscillation and increased energetic fluctuation between the CD3-TCR and CD3-lipids. These atomic-level simulations provide mechanistic insight on how the CD4 coreceptor impacts TCR-pMHC (dis)engagement. More specifically, our results provide further support (enhanced bond lifetime) for a force-dependent kinetic proofreading model and identify an alternate set of amino acids in the TCR that dominate the TCR-pMHC interaction and could thus impact the design of TCRs for immunotherapy.
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Affiliation(s)
- Zachary A Rollins
- Department of Chemical Engineering, University of California, Davis, Davis, California
| | - Roland Faller
- Department of Chemical Engineering, University of California, Davis, Davis, California
| | - Steven C George
- Department of Biomedical Engineering, University of California, Davis, Davis, California.
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3
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Chong G, MacKerell AD. Spatial requirements for ITAM signaling in an intracellular natural killer cell model membrane. Biochim Biophys Acta Gen Subj 2022; 1866:130221. [PMID: 35933027 PMCID: PMC9420803 DOI: 10.1016/j.bbagen.2022.130221] [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: 04/29/2022] [Revised: 07/27/2022] [Accepted: 07/31/2022] [Indexed: 11/17/2022]
Abstract
FcγRIIIa-FcεRIγ complexes, upon stimulation by antibodies, cluster to initiate intracellular signaling and activate natural killer (NK) cells. Intracellular signaling involves Lck phosphorylation of ITAMs of each monomer of a FcεRIγ homodimer in a FcγRIIIa-FcεRIγ complex and subsequent binding of two phosphotyrosines (pY) in tandem by a Syk family kinase. However, how FcR clustering triggers ITAM signaling is not resolved. Molecular modeling and dynamics (MD) simulations are applied to generate ensembles of structures of the FcγRIIIa and FcεRIγ homodimeric cytoplasmic tails of FcγRIIIa-FcεRIγ complexes based on the transmembrane helices and cytoplasmic tails spaced 120, 80, and 50 Å apart to model different extents of clustering. Site-identification by ligand competitive saturation method with Monte Carlo sampling (SILCS-MC) is used to model how Lck could phosphorylate a diversity of ITAM conformations. At 80 Å separation between FcγRIIIa-FcεRIγ complexes, Lck can perform multiple phosphorylations on individual and multiple ITAMs across complexes, including potential sequential phosphorylation events. Syk may then potentially bind the two pYs within a single ITAM in tandem in isolated FcγRIIIa-FcεRIγ complexes, as observed in CD3ε and ζ chains of T cell receptors by the Syk family kinase ZAP-70. In addition, at 50 Å separation between complexes, unique to natural killer cells over T cells, Syk could potentially bind in tandem to pYs in different ITAMs across FcγRIIIa-FcεRIγ complexes. Thus, we predict that an ensemble of spatial orientations of the ITAMS of FcγRIIIa-FcεRIγ complexes that occur upon clustering lead to ITAM phosphorylation by Lck and subsequent Syk activity thereby facilitating downstream signaling.
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Affiliation(s)
- Gene Chong
- Computer Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, United States
| | - Alexander D MacKerell
- Computer Aided Drug Design Center, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, United States.
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4
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Clemens L, Dushek O, Allard J. Intrinsic Disorder in the T Cell Receptor Creates Cooperativity and Controls ZAP70 Binding. Biophys J 2020; 120:379-392. [PMID: 33285117 PMCID: PMC7840419 DOI: 10.1016/j.bpj.2020.11.2266] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/24/2020] [Accepted: 11/19/2020] [Indexed: 12/31/2022] Open
Abstract
Many immunoreceptors have cytoplasmic domains that are intrinsically disordered (i.e., have high configurational entropy), have multiple sites of posttranslational modification (e.g., tyrosine phosphorylation), and participate in nonlinear signaling pathways (e.g., exhibiting switch-like behavior). Several hypotheses to explain the origin of these nonlinearities fall under the broad hypothesis that modification at one site changes the immunoreceptor’s entropy, which in turn changes further modification dynamics. Here, we use coarse-grain simulation to study three scenarios, all related to the chains that constitute the T cell receptor (TCR). We find that first, if phosphorylation induces local changes in the flexibility of the TCR ζ-chain, this naturally leads to rate enhancements and cooperativity. Second, we find that TCR CD3ɛ can provide a switch by modulating its residence in the plasma membrane. By constraining our model to be consistent with the previous observation that both basic residues and phosphorylation control membrane residence, we find that there is only a moderate rate enhancement of 10% between first and subsequent phosphorylation events. Third, we find that volume constraints do not limit the number of ZAP70s that can bind the TCR but that entropic penalties lead to a 200-fold decrease in binding rate by the seventh ZAP70, potentially explaining the observation that each TCR has around six ZAP70 molecules bound after receptor triggering. In all three scenarios, our results demonstrate that phenomena that change an immunoreceptor chain’s entropy (stiffening, confinement to a membrane, and multiple simultaneous binding) can lead to nonlinearities (rate enhancement, switching, and negative cooperativity) in how the receptor participates in signaling. These polymer-entropy-driven nonlinearities may augment the nonlinearities that arise from, e.g., kinetic proofreading and cluster formation. They also suggest different design strategies for engineered receptors, e.g., whether or not to put signaling modules on one chain or multiple clustered chains.
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Affiliation(s)
- Lara Clemens
- Center for Complex Biological Systems, University of California Irvine, Irvine, California
| | - Omer Dushek
- Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Jun Allard
- Center for Complex Biological Systems, University of California Irvine, Irvine, California; Department of Mathematics and Department of Physics and Astronomy, University of California Irvine, Irvine, California.
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5
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Vázquez-Martínez JA, Gómez-Lim MA, Morales-Ríos E, Gonzalez-y-Merchand JA, Ortiz-Navarrete V. Short Disordered Epitope of CRTAM Ig-Like V Domain as a Potential Target for Blocking Antibodies. Int J Mol Sci 2020; 21:ijms21228798. [PMID: 33233764 PMCID: PMC7699905 DOI: 10.3390/ijms21228798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 11/25/2022] Open
Abstract
Class-I Restricted T Cell-Associated Molecule (CRTAM) is a protein that is expressed after T cell activation. The interaction of CRTAM with its ligand, nectin-like 2 (Necl2), is required for the efficient production of IL-17, IL-22, and IFNγ by murine CD4 T cells, and it plays a role in optimal CD8 T and NK cell cytotoxicity. CRTAM promotes the pro-inflammatory cytokine profile; therefore, it may take part in the immunopathology of autoimmune diseases such as diabetes type 1 or colitis. Thus, antibodies that block the interaction between CRTAM and Necl2 would be useful for controlling the production of these inflammatory cytokines. In this work, using bioinformatics predictions, we identified three short disordered epitopes (sDE1-3) that are located in the Ig-like domains of murine CRTAM and are conserved in mammalian species. We performed a structural analysis by molecular dynamics simulations of sDE1 (QHPALKSSKY, Ig-like V), sDE2 (QRNGEKSVVK, Ig-like C1), and sDE3 (CSTERSKKPPPQI, Ig-like C1). sDE1, which is located within a loop of the contact interface of the heterotypic interaction with Nectl2, undergoes an order–disorder transition. On the contrary, even though sDE2 and sDE3 are flexible and also located within loops, they do not undergo order–disorder transitions. We evaluated the immunogenicity of sDE1 and sDE3 through the expression of these epitopes in chimeric L1 virus-like particles. We confirmed that sDE1 induces polyclonal antibodies that recognize the native folding of CRTAM expressed in activated murine CD4 T cells. In contrast, sDE3 induces polyclonal antibodies that recognize the recombinant protein hCRTAM-Fc, but not the native CRTAM. Thus, in this study, an exposed disordered epitope in the Ig-like V domain of CRTAM was identified as a potential site for therapeutic antibodies.
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Affiliation(s)
- Julio Angel Vázquez-Martínez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 Ciudad de Mexico, Mexico; (J.A.V.-M.); (J.A.G.-y.-M.)
- Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), 07360 Ciudad de Mexico, Mexico
- Departamento de Ingeniería Genética, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), 36821 Irapuato, Guanajuato, Mexico;
| | - Miguel Angel Gómez-Lim
- Departamento de Ingeniería Genética, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), 36821 Irapuato, Guanajuato, Mexico;
| | - Edgar Morales-Ríos
- Departamento de Bioquímica, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), 07360 Ciudad de Mexico, Mexico;
| | - Jorge Alberto Gonzalez-y-Merchand
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 Ciudad de Mexico, Mexico; (J.A.V.-M.); (J.A.G.-y.-M.)
| | - Vianney Ortiz-Navarrete
- Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), 07360 Ciudad de Mexico, Mexico
- Correspondence:
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6
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Schamel WW, Alarcon B, Minguet S. The TCR is an allosterically regulated macromolecular machinery changing its conformation while working. Immunol Rev 2020; 291:8-25. [PMID: 31402501 DOI: 10.1111/imr.12788] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 05/30/2019] [Indexed: 12/13/2022]
Abstract
The αβ T-cell receptor (TCR) is a multiprotein complex controlling the activation of T cells. Although the structure of the complete TCR is not known, cumulative evidence supports that the TCR cycles between different conformational states that are promoted either by thermal motion or by force. These structural transitions determine whether the TCR engages intracellular effectors or not, regulating TCR phosphorylation and signaling. As for other membrane receptors, ligand binding selects and stabilizes the TCR in active conformations, and/or switches the TCR to activating states that were not visited before ligand engagement. Here we review the main models of TCR allostery, that is, ligand binding at TCRαβ changes the structure at CD3 and ζ. (a) The ITAM and proline-rich sequence exposure model, in which the TCR's cytoplasmic tails shield each other and ligand binding exposes them for phosphorylation. (b) The membrane-ITAM model, in which the CD3ε and ζ tails are sequestered inside the membrane and again ligand binding exposes them. (c) The mechanosensor model in which ligand binding exerts force on the TCR, inducing structural changes that allow signaling. Since these models are complementary rather than competing, we propose a unified model that aims to incorporate all existing data.
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Affiliation(s)
- Wolfgang W Schamel
- Department of Immunology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
| | - Balbino Alarcon
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Susana Minguet
- Department of Immunology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
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7
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Dong R, Tan Y, Fan A, Liao Z, Liu H, Wei P. Molecular Dynamics of the Recruitment of Immunoreceptor Signaling Module DAP12 Homodimer to Lipid Raft Boundary Regulated by PIP2. J Phys Chem B 2020; 124:504-510. [PMID: 31888335 DOI: 10.1021/acs.jpcb.9b11095] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipid raft microdomain of the plasma membrane is implicated in various biological and pathological processes. The involvement of lipid raft in T cell receptor (TCR) signal transduction has been widely studied, whereas the role of these structures in immunoreceptor signaling by DAP12 in natural killing (NK) cells remains largely unknown. Here, we demonstrate that phosphatidylinositol 4,5-bisphosphate (PIP2) lipid localized to lipid raft boundary in our coarse-grained (CG) model raft-forming membrane, and this negatively charged lipid recruits DAP12 homodimer into lipid raft boundary through protein-lipid interaction between the basic-rich regions and signaling immunoreceptor tyrosine-based activation motifs (ITAMs) of DAP12 and PIP2. Furthermore, our results reveal that the protein-lipid interaction can be disrupted by Ca2+, which competitively binds to PIP2 instead of DAP12. As a result, the cytoplasmic region of DAP12 homodimer is dissociated from the membrane back to the nonraft domain, and the ITAMs are exposed to allow further downstream signaling. These findings provide fundamental insights to understand the mechanism of signal transduction in NK cells regulated by membrane microenvironment.
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Affiliation(s)
- Ruijuan Dong
- School of Traditional Chinese Medicine , Beijing University of Chinese Medicine , Beijing 100029 , China.,Beijing Key Laboratory of Bioprocess, College of Life Science and Technology , Beijing University of Chemical Technology , Beijing 100029 , China
| | - Yan Tan
- School of Life Science , Beijing University of Chinese Medicine , Beijing 100029 , China
| | - Angran Fan
- School of Traditional Chinese Medicine , Beijing University of Chinese Medicine , Beijing 100029 , China
| | - Zehuan Liao
- School of Biological Sciences , Nanyang Technological University , Singapore 637551.,Department of Microbiology, Tumor, and Cell Biology (MTC) , Karolinska Institute , Stockholm 17177 , Sweden
| | - Hangrui Liu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology , Beijing University of Chemical Technology , Beijing 100029 , China
| | - Peng Wei
- School of Traditional Chinese Medicine , Beijing University of Chinese Medicine , Beijing 100029 , China.,Beijing Key Laboratory of Bioprocess, College of Life Science and Technology , Beijing University of Chemical Technology , Beijing 100029 , China
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8
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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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9
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Travers T, Kanagy WK, Mansbach RA, Jhamba E, Cleyrat C, Goldstein B, Lidke DS, Wilson BS, Gnanakaran S. Combinatorial diversity of Syk recruitment driven by its multivalent engagement with FcεRIγ. Mol Biol Cell 2019; 30:2331-2347. [PMID: 31216232 PMCID: PMC6743456 DOI: 10.1091/mbc.e18-11-0722] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 05/17/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
Syk/Zap70 family kinases are essential for signaling via multichain immune-recognition receptors such as tetrameric (αβγ2) FcεRI. Syk activation is generally attributed to cis binding of its tandem SH2 domains to dual phosphotyrosines within FcεRIγ-ITAMs (immunoreceptor tyrosine-based activation motifs). However, the mechanistic details of Syk docking on γ homodimers are unresolved. Here, we estimate that multivalent interactions for WT Syk improve cis-oriented binding by three orders of magnitude. We applied molecular dynamics (MD), hybrid MD/worm-like chain polymer modeling, and live cell imaging to evaluate relative binding and signaling output for all possible cis and trans Syk-FcεRIγ configurations. Syk binding is likely modulated during signaling by autophosphorylation on Y130 in interdomain A, since a Y130E phosphomimetic form of Syk is predicted to lead to reduced helicity of interdomain A and alter Syk's bias for cis binding. Experiments in reconstituted γ-KO cells, whose γ subunits are linked by disulfide bonds, as well as in cells expressing monomeric ITAM or hemITAM γ-chimeras, support model predictions that short distances between γ ITAM pairs are required for trans docking. We propose that the full range of docking configurations improves signaling efficiency by expanding the combinatorial possibilities for Syk recruitment, particularly under conditions of incomplete ITAM phosphorylation.
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Affiliation(s)
- Timothy Travers
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - William K. Kanagy
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Rachael A. Mansbach
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Elton Jhamba
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Cedric Cleyrat
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Byron Goldstein
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Diane S. Lidke
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Bridget S. Wilson
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - S. Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM 87545
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10
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Marrink SJ, Corradi V, Souza PC, Ingólfsson HI, Tieleman DP, Sansom MS. Computational Modeling of Realistic Cell Membranes. Chem Rev 2019; 119:6184-6226. [PMID: 30623647 PMCID: PMC6509646 DOI: 10.1021/acs.chemrev.8b00460] [Citation(s) in RCA: 422] [Impact Index Per Article: 84.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Indexed: 12/15/2022]
Abstract
Cell membranes contain a large variety of lipid types and are crowded with proteins, endowing them with the plasticity needed to fulfill their key roles in cell functioning. The compositional complexity of cellular membranes gives rise to a heterogeneous lateral organization, which is still poorly understood. Computational models, in particular molecular dynamics simulations and related techniques, have provided important insight into the organizational principles of cell membranes over the past decades. Now, we are witnessing a transition from simulations of simpler membrane models to multicomponent systems, culminating in realistic models of an increasing variety of cell types and organelles. Here, we review the state of the art in the field of realistic membrane simulations and discuss the current limitations and challenges ahead.
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Affiliation(s)
- Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Valentina Corradi
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Paulo C.T. Souza
- Groningen
Biomolecular Sciences and Biotechnology Institute & Zernike Institute
for Advanced Materials, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Helgi I. Ingólfsson
- Biosciences
and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, United States
| | - D. Peter Tieleman
- Centre
for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Mark S.P. Sansom
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
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11
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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12
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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13
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Börtlein C, Draeger A, Schoenauer R, Kuhlemann A, Sauer M, Schneider-Schaulies S, Avota E. The Neutral Sphingomyelinase 2 Is Required to Polarize and Sustain T Cell Receptor Signaling. Front Immunol 2018; 9:815. [PMID: 29720981 PMCID: PMC5915489 DOI: 10.3389/fimmu.2018.00815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/04/2018] [Indexed: 01/02/2023] Open
Abstract
By promoting ceramide release at the cytosolic membrane leaflet, the neutral sphingomyelinase 2 (NSM) is capable of organizing receptor and signalosome segregation. Its role in T cell receptor (TCR) signaling remained so far unknown. We now show that TCR-driven NSM activation is dispensable for TCR clustering and initial phosphorylation, but of crucial importance for further signal amplification. In particular, at low doses of TCR stimulatory antibodies, NSM is required for Ca2+ mobilization and T cell proliferation. NSM-deficient T cells lack sustained CD3ζ and ZAP-70 phosphorylation and are unable to polarize and stabilize their microtubular system. We identified PKCζ as the key NSM downstream effector in this second wave of TCR signaling supporting dynamics of microtubule-organizing center (MTOC). Ceramide supplementation rescued PKCζ membrane recruitment and MTOC translocation in NSM-deficient cells. These findings identify the NSM as essential in TCR signaling when dynamic cytoskeletal reorganization promotes continued lateral and vertical supply of TCR signaling components: CD3ζ, Zap70, and PKCζ, and functional immune synapses are organized and stabilized via MTOC polarization.
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Affiliation(s)
- Charlene Börtlein
- Institute for Virology and Immunobiology, University of Wuerzburg, Wuerzburg, Germany
| | - Annette Draeger
- Department of Cell Biology, Institute for Anatomy, University of Bern, Bern, Switzerland
| | - Roman Schoenauer
- Department of Cell Biology, Institute for Anatomy, University of Bern, Bern, Switzerland
| | - Alexander Kuhlemann
- Department of Biotechnology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Wuerzburg, Wuerzburg, Germany
| | | | - Elita Avota
- Institute for Virology and Immunobiology, University of Wuerzburg, Wuerzburg, Germany
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14
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Affiliation(s)
- Ferenc Zsila
- Biomolecular Self-Assembly Group; Institute of Materials and Environmental Chemistry; Research Centre for Natural Sciences; Hungarian Academy of Sciences; 1117 Budapest Hungary
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15
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Membrane perturbing properties of toxin mycolactone from Mycobacterium ulcerans. PLoS Comput Biol 2018; 14:e1005972. [PMID: 29401455 PMCID: PMC5814095 DOI: 10.1371/journal.pcbi.1005972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 02/15/2018] [Accepted: 01/15/2018] [Indexed: 12/16/2022] Open
Abstract
Mycolactone is the exotoxin produced by Mycobacterium ulcerans and is the virulence factor behind the neglected tropical disease Buruli ulcer. The toxin has a broad spectrum of biological effects within the host organism, stemming from its interaction with at least two molecular targets and the inhibition of protein uptake into the endoplasmic reticulum. Although it has been shown that the toxin can passively permeate into host cells, it is clearly lipophilic. Association with lipid carriers would have substantial implications for the toxin’s distribution within a host organism, delivery to cellular targets, diagnostic susceptibility, and mechanisms of pathogenicity. Yet the toxin’s interactions with, and distribution in, lipids are unknown. Herein we have used coarse-grained molecular dynamics simulations, guided by all-atom simulations, to study the interaction of mycolactone with pure and mixed lipid membranes. Using established techniques, we calculated the toxin’s preferential localization, membrane translocation, and impact on membrane physical and dynamical properties. The computed water-octanol partition coefficient indicates that mycolactone prefers to be in an organic phase rather than in an aqueous environment. Our results show that in a solvated membrane environment the exotoxin mainly localizes in the water-membrane interface, with a preference for the glycerol moiety of lipids, consistent with the reported studies that found it in lipid extracts of the cell. The calculated association constant to the model membrane is similar to the reported association constant for Wiskott-Aldrich syndrome protein. Mycolactone is shown to modify the physical properties of membranes, lowering the transition temperature, compressibility modulus, and critical line tension at which pores can be stabilized. It also shows a tendency to behave as a linactant, a molecule that localizes at the boundary between different fluid lipid domains in membranes and promotes inter-mixing of domains. This property has implications for the toxin’s cellular access, T-cell immunosuppression, and therapeutic potential. Mycolactone is a macrolide exotoxin secreted by Mycobacterium ulcerans, which causes a skin disease called Buruli ulcer, a neglected emerging disease. It is the third most common mycobacterial disease after tuberculosis and leprosy. Studies have shown how mycolactone plays a pivotal role in Buruli ulcer pathogenesis, and identified it as an attractive therapeutic target. This multifunctional cytotoxin exerts multiple local and global responses, including ulcerative, analgesic, and anti-inflammatory effects. Prompted by its lipid-like structure, we used extensive multi-resolution simulations to probe mycolactone’s interactions with model membranes. Our results suggest that mycolactone is sequestered in membranes where it alters several dynamical, physical, and mechanical properties. It also behaves as a linactant, localizing at the interface between lipid domains and decreasing the inter-domain line tension. Our results shed light on how mycolactone permeates host cell membranes and is distributed between lipid and aqueous environments. These findings have significant implications for the toxin’s distribution in the host environment and mechanisms of pathogenicity. Understanding the toxin’s distribution and mechanism of trafficking will have ramifications for targeted diagnostics, therapeutic approaches, and our understanding of Buruli ulcer pathogenesis.
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16
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Kjaergaard M, Kragelund BB. Functions of intrinsic disorder in transmembrane proteins. Cell Mol Life Sci 2017; 74:3205-3224. [PMID: 28601983 PMCID: PMC11107515 DOI: 10.1007/s00018-017-2562-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022]
Abstract
Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine receptors. The functions of the disordered regions are many and varied. We will discuss selected examples including: (1) Organization of receptors, kinases, phosphatases and second messenger sources into signaling complexes. (2) Modulation of the membrane-embedded domain function by ball-and-chain like mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding protein disorder.
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Affiliation(s)
- Magnus Kjaergaard
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- The Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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17
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Schwartz SL, Cleyrat C, Olah MJ, Relich PK, Phillips GK, Hlavacek WS, Lidke KA, Wilson BS, Lidke DS. Differential mast cell outcomes are sensitive to FcεRI-Syk binding kinetics. Mol Biol Cell 2017; 28:3397-3414. [PMID: 28855374 PMCID: PMC5687039 DOI: 10.1091/mbc.e17-06-0350] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 11/11/2022] Open
Abstract
Cross-linking of immunoglobulin E-bound FcεRI triggers multiple cellular responses, including degranulation and cytokine production. Signaling is dependent on recruitment of Syk via docking of its dual SH2 domains to phosphorylated tyrosines within the FcεRI immunoreceptor tyrosine-based activation motifs. Using single-molecule imaging in live cells, we directly visualized and quantified the binding of individual mNeonGreen-tagged Syk molecules as they associated with the plasma membrane after FcεRI activation. We found that Syk colocalizes transiently to FcεRI and that Syk-FcεRI binding dynamics are independent of receptor aggregate size. Substitution of glutamic acid for tyrosine between the Syk SH2 domains (Syk-Y130E) led to an increased Syk-FcεRI off-rate, loss of site-specific Syk autophosphorylation, and impaired downstream signaling. Genome edited cells expressing only Syk-Y130E were deficient in antigen-stimulated calcium release, degranulation, and production of some cytokines (TNF-a, IL-3) but not others (MCP-1, IL-4). We propose that kinetic discrimination along the FcεRI signaling pathway occurs at the level of Syk-FcεRI interactions, with key outcomes dependent upon sufficiently long-lived Syk binding events.
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Affiliation(s)
- Samantha L Schwartz
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Cédric Cleyrat
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Mark J Olah
- Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Peter K Relich
- Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Genevieve K Phillips
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - William S Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Keith A Lidke
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131.,Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Bridget S Wilson
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Diane S Lidke
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131 .,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
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