1
|
Horna P, Shi M, Olteanu H, Johansson U. Emerging Role of T-cell Receptor Constant β Chain-1 (TRBC1) Expression in the Flow Cytometric Diagnosis of T-cell Malignancies. Int J Mol Sci 2021; 22:ijms22041817. [PMID: 33673033 PMCID: PMC7918842 DOI: 10.3390/ijms22041817] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 02/07/2023] Open
Abstract
T-cell clonality testing is integral to the diagnostic work-up of T-cell malignancies; however, current methods lack specificity and sensitivity, which can make the diagnostic process difficult. The recent discovery of a monoclonal antibody (mAb) specific for human TRBC1 will greatly improve the outlook for T-cell malignancy diagnostics. The anti-TRBC1 mAb can be used in flow cytometry immunophenotyping assays to provide a low-cost, robust, and highly specific test that detects clonality of immunophenotypically distinct T-cell populations. Recent studies demonstrate the clinical utility of this approach in several contexts; use of this antibody in appropriately designed flow cytometry panels improves detection of circulating disease in patients with cutaneous T-cell lymphoma, eliminates the need for molecular clonality testing in the context of large granular lymphocyte leukemia, and provides more conclusive results in the context of many other T-cell disorders. It is worth noting that the increased ability to detect discrete clonal T-cell populations means that identification of T-cell clones of uncertain clinical significance (T-CUS) will become more common. This review discusses this new antibody and describes how it defines clonal T-cells. We present and discuss assay design and summarize findings to date about the use of flow cytometry TRBC1 analysis in the field of diagnostics, including lymph node and fluid sample investigations. We also make suggestions about how to apply the assay results in clinical work-ups, including how to interpret and report findings of T-CUS. Finally, we highlight areas that we think will benefit from further research.
Collapse
Affiliation(s)
- Pedro Horna
- Division of Hematopathology, Mayo Clinic, Rochester, MN 55905, USA; (P.H.); (M.S.); (H.O.)
| | - Min Shi
- Division of Hematopathology, Mayo Clinic, Rochester, MN 55905, USA; (P.H.); (M.S.); (H.O.)
| | - Horatiu Olteanu
- Division of Hematopathology, Mayo Clinic, Rochester, MN 55905, USA; (P.H.); (M.S.); (H.O.)
| | - Ulrika Johansson
- SI-HMDS, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol BS1 3NU, UK
- Correspondence:
| |
Collapse
|
2
|
Pathan-Chhatbar S, Drechsler C, Richter K, Morath A, Wu W, OuYang B, Xu C, Schamel WW. Direct Regulation of the T Cell Antigen Receptor's Activity by Cholesterol. Front Cell Dev Biol 2021; 8:615996. [PMID: 33490080 PMCID: PMC7820176 DOI: 10.3389/fcell.2020.615996] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 12/09/2020] [Indexed: 11/14/2022] Open
Abstract
Biological membranes consist of hundreds of different lipids that together with the embedded transmembrane (TM) proteins organize themselves into small nanodomains. In addition to this function of lipids, TM regions of proteins bind to lipids in a very specific manner, but the function of these TM region-lipid interactions is mostly unknown. In this review, we focus on the role of plasma membrane cholesterol, which directly binds to the αβ T cell antigen receptor (TCR), and has at least two opposing functions in αβ TCR activation. On the one hand, cholesterol binding to the TM domain of the TCRβ subunit keeps the TCR in an inactive, non-signaling conformation by stabilizing this conformation. This assures that the αβ T cell remains quiescent in the absence of antigenic peptide-MHC (the TCR's ligand) and decreases the sensitivity of the T cell toward stimulation. On the other hand, cholesterol binding to TCRβ leads to an increased formation of TCR nanoclusters, increasing the avidity of the TCRs toward the antigen, thus increasing the sensitivity of the αβ T cell. In mouse models, pharmacological increase of the cholesterol concentration in T cells caused an increase in TCR clustering, and thereby enhanced anti-tumor responses. In contrast, the γδ TCR does not bind to cholesterol and might be regulated in a different manner. The goal of this review is to put these seemingly controversial findings on the impact of cholesterol on the αβ TCR into perspective.
Collapse
Affiliation(s)
- Salma Pathan-Chhatbar
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Carina Drechsler
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Kirsten Richter
- Immunology, Infectious Diseases and Ophthalmology Disease Translational Area, Roche Innovation Center Basel, Basel, Switzerland
| | - Anna Morath
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Wei Wu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Chenqi Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wolfgang W. Schamel
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany
- Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| |
Collapse
|
3
|
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: 54] [Impact Index Per Article: 10.8] [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.
Collapse
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
| |
Collapse
|
4
|
Abstract
T cell receptors (TCRs) are protein complexes formed by six different polypeptides. In most T cells, TCRs are composed of αβ subunits displaying immunoglobulin-like variable domains that recognize peptide antigens associated with major histocompatibility complex molecules expressed on the surface of antigen-presenting cells. TCRαβ subunits are associated with the CD3 complex formed by the γ, δ, ε, and ζ subunits, which are invariable and ensure signal transduction. Here, we review how the expression and function of TCR complexes are orchestrated by several fine-tuned cellular processes that encompass (a) synthesis of the subunits and their correct assembly and expression at the plasma membrane as a single functional complex, (b) TCR membrane localization and dynamics at the plasma membrane and in endosomal compartments, (c) TCR signal transduction leading to T cell activation, and (d) TCR degradation. These processes balance each other to ensure efficient T cell responses to a variety of antigenic stimuli while preventing autoimmunity.
Collapse
Affiliation(s)
- Andrés Alcover
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
| | - Balbino Alarcón
- Severo Ochoa Center for Molecular Biology, CSIC-UAM, Madrid 28049, Spain;
| | - Vincenzo Di Bartolo
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
| |
Collapse
|
5
|
A Cholesterol-Based Allostery Model of T Cell Receptor Phosphorylation. Immunity 2017; 44:1091-101. [PMID: 27192576 DOI: 10.1016/j.immuni.2016.04.011] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 11/17/2015] [Accepted: 04/11/2016] [Indexed: 12/20/2022]
Abstract
Signaling through the T cell receptor (TCR) controls adaptive immune responses. Antigen binding to TCRαβ transmits signals through the plasma membrane to induce phosphorylation of the CD3 cytoplasmic tails by incompletely understood mechanisms. Here we show that cholesterol bound to the TCRβ transmembrane region keeps the TCR in a resting, inactive conformation that cannot be phosphorylated by active kinases. Only TCRs that spontaneously detached from cholesterol could switch to the active conformation (termed primed TCRs) and then be phosphorylated. Indeed, by modulating cholesterol binding genetically or enzymatically, we could switch the TCR between the resting and primed states. The active conformation was stabilized by binding to peptide-MHC, which thus controlled TCR signaling. These data are explained by a model of reciprocal allosteric regulation of TCR phosphorylation by cholesterol and ligand binding. Our results provide both a molecular mechanism and a conceptual framework for how lipid-receptor interactions regulate signal transduction.
Collapse
|
6
|
Schamel WWA, Alarcon B, Höfer T, Minguet S. The Allostery Model of TCR Regulation. THE JOURNAL OF IMMUNOLOGY 2017; 198:47-52. [PMID: 27994168 DOI: 10.4049/jimmunol.1601661] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 11/01/2016] [Indexed: 12/20/2022]
Abstract
The activity of the αβ TCR is controlled by conformational switches. In the resting conformation, the TCR is not phosphorylated and is inactive. Binding of multivalent peptide-MHC to the TCR stabilizes the active conformation, leading to TCR signaling. These two conformations allow the TCRs to be allosterically regulated. We review recent data on heterotropic allostery where peptide-MHC and membrane cholesterol serve opposing functions as positive and negative allosteric regulators, respectively. In resting T cells cholesterol keeps TCRs in the resting conformation that otherwise would become spontaneously active. This regulation is well described by the classical Monod-Wyman-Changeux model of allostery. Moreover, the observation that TCRs assemble into nanoclusters might allow for homotropic allostery, in which individual TCRs could positively cooperate and thus enhance the sensitivity of T cell activation. This new view of TCR regulation will contribute to a better understanding of TCR functioning.
Collapse
Affiliation(s)
- Wolfgang W A Schamel
- Department of Immunology, Institute for Biology III, Faculty of Biology, University of Freiburg, 79108 Freiburg, Germany; .,BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany.,Center for Chronic Immunodeficiency, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Balbino Alarcon
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Thomas Höfer
- Division of Theoretical Systems Biology, German Cancer Research Center, 69120 Heidelberg, Germany; and.,BioQuant Center, University of Heidelberg, 69120 Heidelberg, Germany
| | - Susana Minguet
- Department of Immunology, Institute for Biology III, Faculty of Biology, University of Freiburg, 79108 Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| |
Collapse
|
7
|
Hoffmann MM, Molina-Mendiola C, Nelson AD, Parks CA, Reyes EE, Hansen MJ, Rajagopalan G, Pease LR, Schrum AG, Gil D. Co-potentiation of antigen recognition: A mechanism to boost weak T cell responses and provide immunotherapy in vivo. SCIENCE ADVANCES 2015; 1:e1500415. [PMID: 26601285 PMCID: PMC4646799 DOI: 10.1126/sciadv.1500415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/24/2015] [Indexed: 06/05/2023]
Abstract
Adaptive immunity is mediated by antigen receptors that can induce weak or strong immune responses depending on the nature of the antigen that is bound. In T lymphocytes, antigen recognition triggers signal transduction by clustering T cell receptor (TCR)/CD3 multiprotein complexes. In addition, it hypothesized that biophysical changes induced in TCR/CD3 that accompany receptor engagement may contribute to signal intensity. Nonclustering monovalent TCR/CD3 engagement is functionally inert despite the fact that it may induce changes in conformational arrangement or in the flexibility of receptor subunits. We report that the intrinsically inert monovalent engagement of TCR/CD3 can specifically enhance physiologic T cell responses to weak antigens in vitro and in vivo without stimulating antigen-unengaged T cells and without interrupting T cell responses to strong antigens, an effect that we term as "co-potentiation." We identified Mono-7D6-Fab, which biophysically altered TCR/CD3 when bound and functionally enhanced immune reactivity to several weak antigens in vitro, including a gp100-derived peptide associated with melanoma. In vivo, Mono-7D6-Fab induced T cell antigen-dependent therapeutic responses against melanoma lung metastases, an effect that synergized with other anti-melanoma immunotherapies to significantly improve outcome and survival. We conclude that Mono-7D6-Fab directly co-potentiated TCR/CD3 engagement by weak antigens and that such concept can be translated into an immunotherapeutic design. The co-potentiation principle may be applicable to other receptors that could be regulated by otherwise inert compounds whose latent potency is only invoked in concert with specific physiologic ligands.
Collapse
Affiliation(s)
- Michele M. Hoffmann
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Carlos Molina-Mendiola
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
- Department of Statistics, Polytechnic University of Catalonia, Barcelona 08034, Spain
| | - Alfreda D. Nelson
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Christopher A. Parks
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Edwin E. Reyes
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Michael J. Hansen
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Govindarajan Rajagopalan
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Larry R. Pease
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Adam G. Schrum
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Diana Gil
- Department of Immunology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| |
Collapse
|
8
|
Beck-García K, Beck-García E, Bohler S, Zorzin C, Sezgin E, Levental I, Alarcón B, Schamel WW. Nanoclusters of the resting T cell antigen receptor (TCR) localize to non-raft domains. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:802-9. [DOI: 10.1016/j.bbamcr.2014.12.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 12/04/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
|
9
|
Scrutinizing calcium flux oscillations in T lymphocytes to deduce the strength of stimulus. Sci Rep 2015; 5:7760. [PMID: 25585590 PMCID: PMC4293621 DOI: 10.1038/srep07760] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 12/11/2014] [Indexed: 01/13/2023] Open
Abstract
The capture and activation of individual T cells on functionalised surfaces enables real-time analyses of the magnitude and rhythm of intracellular calcium release. Application of Haarlet transformations generate a calcium flux ‘threshold’, with the frequency of the ‘threshold crossings’ correlating with the strength of the original T cell stimulus. These findings represent a new method to evaluate graduations in T cell activation in real time, and at a single-cell level.
Collapse
|
10
|
Insights into the initiation of TCR signaling. Nat Immunol 2014; 15:798-807. [PMID: 25137454 DOI: 10.1038/ni.2940] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 06/10/2014] [Indexed: 12/13/2022]
Abstract
The initiation of T cell antigen receptor signaling is a key step that can result in T cell activation and the orchestration of an adaptive immune response. Early events in T cell receptor signaling can distinguish between agonist and endogenous ligands with exquisite selectivity, and show extraordinary sensitivity to minute numbers of agonists in a sea of endogenous ligands. We review our current knowledge of models and crucial molecules that aim to provide a mechanistic explanation for these observations. Building on current understanding and a discussion of unresolved issues, we propose a molecular model for initiation of T cell receptor signaling that may serve as a useful guide for future studies.
Collapse
|
11
|
Blanco R, Borroto A, Schamel W, Pereira P, Alarcon B. Conformational changes in the T cell receptor differentially determine T cell subset development in mice. Sci Signal 2014; 7:ra115. [DOI: 10.1126/scisignal.2005650] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
12
|
Chylek LA, Akimov V, Dengjel J, Rigbolt KTG, Hu B, Hlavacek WS, Blagoev B. Phosphorylation site dynamics of early T-cell receptor signaling. PLoS One 2014; 9:e104240. [PMID: 25147952 PMCID: PMC4141737 DOI: 10.1371/journal.pone.0104240] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/07/2014] [Indexed: 11/18/2022] Open
Abstract
In adaptive immune responses, T-cell receptor (TCR) signaling impacts multiple cellular processes and results in T-cell differentiation, proliferation, and cytokine production. Although individual protein-protein interactions and phosphorylation events have been studied extensively, we lack a systems-level understanding of how these components cooperate to control signaling dynamics, especially during the crucial first seconds of stimulation. Here, we used quantitative proteomics to characterize reshaping of the T-cell phosphoproteome in response to TCR/CD28 co-stimulation, and found that diverse dynamic patterns emerge within seconds. We detected phosphorylation dynamics as early as 5 s and observed widespread regulation of key TCR signaling proteins by 30 s. Development of a computational model pointed to the presence of novel regulatory mechanisms controlling phosphorylation of sites with central roles in TCR signaling. The model was used to generate predictions suggesting unexpected roles for the phosphatase PTPN6 (SHP-1) and shortcut recruitment of the actin regulator WAS. Predictions were validated experimentally. This integration of proteomics and modeling illustrates a novel, generalizable framework for solidifying quantitative understanding of a signaling network and for elucidating missing links.
Collapse
Affiliation(s)
- Lily A. Chylek
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States of America
| | - Vyacheslav Akimov
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Jörn Dengjel
- Department of Dermatology, Medical Center; Freiburg Institute for Advanced Studies (FRIAS); BIOSS Centre for Biological Signalling Studies; ZBSA Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Kristoffer T. G. Rigbolt
- Department of Dermatology, Medical Center; Freiburg Institute for Advanced Studies (FRIAS); BIOSS Centre for Biological Signalling Studies; ZBSA Center for Biological Systems Analysis, University of Freiburg, Freiburg, Germany
| | - Bin Hu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - William S. Hlavacek
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Blagoy Blagoev
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| |
Collapse
|
13
|
Dopfer E, Hartl F, Oberg HH, Siegers G, Yousefi OS, Kock S, Fiala G, Garcillán B, Sandstrom A, Alarcón B, Regueiro J, Kabelitz D, Adams E, Minguet S, Wesch D, Fisch P, Schamel W. The CD3 Conformational Change in the γδ T Cell Receptor Is Not Triggered by Antigens but Can Be Enforced to Enhance Tumor Killing. Cell Rep 2014; 7:1704-1715. [DOI: 10.1016/j.celrep.2014.04.049] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 03/15/2014] [Accepted: 04/23/2014] [Indexed: 12/24/2022] Open
|
14
|
Spina CA, Anderson J, Archin NM, Bosque A, Chan J, Famiglietti M, Greene WC, Kashuba A, Lewin SR, Margolis DM, Mau M, Ruelas D, Saleh S, Shirakawa K, Siliciano RF, Singhania A, Soto PC, Terry VH, Verdin E, Woelk C, Wooden S, Xing S, Planelles V. An in-depth comparison of latent HIV-1 reactivation in multiple cell model systems and resting CD4+ T cells from aviremic patients. PLoS Pathog 2013; 9:e1003834. [PMID: 24385908 PMCID: PMC3873446 DOI: 10.1371/journal.ppat.1003834] [Citation(s) in RCA: 342] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/30/2013] [Indexed: 01/01/2023] Open
Abstract
The possibility of HIV-1 eradication has been limited by the existence of latently infected cellular reservoirs. Studies to examine control of HIV latency and potential reactivation have been hindered by the small numbers of latently infected cells found in vivo. Major conceptual leaps have been facilitated by the use of latently infected T cell lines and primary cells. However, notable differences exist among cell model systems. Furthermore, screening efforts in specific cell models have identified drug candidates for "anti-latency" therapy, which often fail to reactivate HIV uniformly across different models. Therefore, the activity of a given drug candidate, demonstrated in a particular cellular model, cannot reliably predict its activity in other cell model systems or in infected patient cells, tested ex vivo. This situation represents a critical knowledge gap that adversely affects our ability to identify promising treatment compounds and hinders the advancement of drug testing into relevant animal models and clinical trials. To begin to understand the biological characteristics that are inherent to each HIV-1 latency model, we compared the response properties of five primary T cell models, four J-Lat cell models and those obtained with a viral outgrowth assay using patient-derived infected cells. A panel of thirteen stimuli that are known to reactivate HIV by defined mechanisms of action was selected and tested in parallel in all models. Our results indicate that no single in vitro cell model alone is able to capture accurately the ex vivo response characteristics of latently infected T cells from patients. Most cell models demonstrated that sensitivity to HIV reactivation was skewed toward or against specific drug classes. Protein kinase C agonists and PHA reactivated latent HIV uniformly across models, although drugs in most other classes did not.
Collapse
Affiliation(s)
- Celsa A. Spina
- Veterans Administration San Diego Healthcare System, San Diego, California, United States of America
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Jenny Anderson
- Department of Infectious Diseases, Alfred Hospital, Melbourne, Australia
| | - Nancie M. Archin
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Alberto Bosque
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jonathan Chan
- Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Marylinda Famiglietti
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Warner C. Greene
- Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Angela Kashuba
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Sharon R. Lewin
- Department of Infectious Diseases, Alfred Hospital, Melbourne, Australia
- Monash University, Melbourne, Australia
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia
| | - David M. Margolis
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Matthew Mau
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Debbie Ruelas
- Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Suha Saleh
- Department of Infectious Diseases, Alfred Hospital, Melbourne, Australia
| | - Kotaro Shirakawa
- Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Robert F. Siliciano
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Baltimore, Maryland, United States of America
| | - Akul Singhania
- Veterans Administration San Diego Healthcare System, San Diego, California, United States of America
| | - Paula C. Soto
- Veterans Administration San Diego Healthcare System, San Diego, California, United States of America
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Valeri H. Terry
- Veterans Administration San Diego Healthcare System, San Diego, California, United States of America
| | - Eric Verdin
- Gladstone Institute of Virology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Christopher Woelk
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Stacey Wooden
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Sifei Xing
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Howard Hughes Medical Institute, Baltimore, Maryland, United States of America
| | - Vicente Planelles
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
| |
Collapse
|
15
|
Nelson AD, Hoffmann MM, Parks CA, Dasari S, Schrum AG, Gil D. IgG Fab fragments forming bivalent complexes by a conformational mechanism that is reversible by osmolytes. J Biol Chem 2012; 287:42936-50. [PMID: 23109335 DOI: 10.1074/jbc.m112.410217] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Generated by proteolytic cleavage of immunoglobulin, Fab fragments possess great promise as blocking reagents, able to bind receptors or other targets without inducing cross-linking. However, aggregation of Fab preparations is a common occurrence, which generates intrinsic stimulatory capacity and thwarts signal blockade strategies. Using a panel of biochemical approaches, including size exclusion chromatography, SDS-PAGE, mass spectrometry, and cell stimulation followed by flow cytometry, we have measured the oligomerization and acquisition of stimulatory capacity that occurs in four monoclonal IgG Fabs specific for TCR/CD3. Unexpectedly, we observed that all Fabs spontaneously formed complexes that were precisely bivalent, and these bivalent complexes possessed most of the stimulatory activity of each Fab preparation. Fabs composing bivalent complexes were more susceptible to proteolysis than monovalent Fabs, indicating a difference in conformation between the Fabs involved in these two different states of valency. Because osmolytes represent a class of compounds that stabilize protein folding and conformation, we sought to determine the extent to which the amino acid osmolyte l-proline might impact bivalent Fab complexation. We found that l-proline (i) inhibited the adoption of the conformation associated with bivalent complexation, (ii) preserved Fab monovalency, (iii) reversed the conformation of preformed bivalent Fabs to that of monovalent Fabs, and (iv) separated a significant percentage of preformed bivalent complexes into monovalent species. Thus, Fab fragments can adopt a conformation that is compatible with folding or packing of a bivalent complex in a process that can be inhibited by osmolytes.
Collapse
Affiliation(s)
- Alfreda D Nelson
- Department of Immunology, Center for Individualized Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | | | | | | | | | | |
Collapse
|
16
|
Blanco R, Alarcón B. TCR Nanoclusters as the Framework for Transmission of Conformational Changes and Cooperativity. Front Immunol 2012; 3:115. [PMID: 22582078 PMCID: PMC3348506 DOI: 10.3389/fimmu.2012.00115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/22/2012] [Indexed: 12/30/2022] Open
Abstract
Increasing evidence favors the notion that, before triggering, the T cell antigen receptor (TCR) forms nanometer-scale oligomers that are called nanoclusters. The organization of the TCR in pre-existing oligomers cannot be ignored when analyzing the properties of ligand (pMHC) recognition and signal transduction. As with other membrane receptors, the existence of TCR oligomers points out to cooperativity phenomena. We review the data in support of conformational changes in the TCR as the basic principle to transduce the activation signal to the cytoplasm and the incipient data suggesting cooperativity within nanoclusters.
Collapse
Affiliation(s)
- Raquel Blanco
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid Madrid, Spain
| | | |
Collapse
|
17
|
Louis-Dit-Sully C, Kubatzky KF, Lindquist JA, Blattner C, Janssen O, Schamel WWA. Meeting report: Signal transduction meets systems biology. Cell Commun Signal 2012; 10:11. [PMID: 22546078 PMCID: PMC3499392 DOI: 10.1186/1478-811x-10-11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/07/2012] [Indexed: 11/18/2022] Open
Abstract
In the 21st century, systems-wide analyses of biological processes are getting more and more realistic. Especially for the in depth analysis of signal transduction pathways and networks, various approaches of systems biology are now successfully used. The EU FP7 large integrated project SYBILLA (Systems Biology of T-cell Activation in Health and Disease) coordinates such an endeavor. By using a combination of experimental data sets and computational modelling, the consortium strives for gaining a detailed and mechanistic understanding of signal transduction processes that govern T-cell activation. In order to foster the interaction between systems biologists and experimentally working groups, SYBILLA co-organized the 15th meeting “Signal Transduction: Receptors, Mediators and Genes” together with the Signal Transduction Society (STS). Thus, the annual STS conference, held from November 7 to 9, 2011 in Weimar, Germany, provided an interdisciplinary forum for research on signal transduction with a major focus on systems biology addressing signalling events in T-cells. Here we report on a selection of ongoing projects of SYBILLA and how they were discussed at this interdisciplinary conference.
Collapse
Affiliation(s)
- Christine Louis-Dit-Sully
- Max Planck Institute of Immunobiology and Epigenetics and Biology III, Faculty of Biology, University of Freiburg, 79108, Freiburg, Germany.
| | | | | | | | | | | |
Collapse
|
18
|
Basic residues in the T-cell receptor ζ cytoplasmic domain mediate membrane association and modulate signaling. Proc Natl Acad Sci U S A 2011; 108:19323-8. [PMID: 22084078 DOI: 10.1073/pnas.1108052108] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The T-cell receptor (TCR) consists of a TCRαβ heterodimer, a TCRζ homodimer, and CD3γε and CD3δε heterodimers. The precise mechanism of T-cell triggering following TCR ligand engagement remains elusive. Previous studies reported that the cytoplasmic tail of CD3ε binds to the plasma membrane through a basic residue-rich stretch (BRS) and proposed that dissociation from the membrane is required for phosphorylation thereof. In this report we show that BRS motifs within the cytoplasmic tail of TCRζ mediate association with the plasma membrane and that TCR engagement results in TCRζ dissociation from the membrane. This dissociation requires phosphorylation of the TCRζ immunoreceptor tyrosine-based activation motifs by lymphocyte cell-specificprotein tyrosine kinase (Lck) but not ζ-chain-associated protein kinase 70 binding. Mutations of the TCRζ BRS motifs that disrupt this membrane association attenuate proximal and distal responses induced by TCR engagement. These mutations appear to alter the localization of TCRζ with respect to Lck as well as the mobility of the TCR complex. This study reveals that tyrosine phosphorylation of the TCRζ cytoplasmic domain regulates its association with the plasma membrane and highlights the functional importance of TCRζ BRS motifs.
Collapse
|
19
|
Abstract
There is considerable controversy about the mechanism of T cell receptor (TCR) triggering, the process by which the TCR tranduces signals across the plasma membrane after binding to its ligand (an agonist peptide complexed with an MHC molecule). Three main types of mechanism have been proposed, which involve aggregation, conformational change and segregation. Here, we review recently published evidence for each type of mechanism and conclude that all three may be involved. This complexity may reflect the uniquely demanding nature of TCR-mediated antigen recognition, which requires the detection of a very weak 'signal' (very rare foreign peptide-MHC ligands) in the presence of considerable 'noise' (abundant self peptide-MHC molecules).
Collapse
|
20
|
Detection of phosphorylated T and B cell antigen receptor species by Phos-tag SDS- and Blue Native-PAGE. Immunol Lett 2010; 130:51-6. [DOI: 10.1016/j.imlet.2009.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 11/30/2009] [Accepted: 12/02/2009] [Indexed: 01/31/2023]
|
21
|
Swamy M, Siegers GM, Fiala GJ, Molnar E, Dopfer EP, Fisch P, Schraven B, Schamel WWA. Stoichiometry and intracellular fate of TRIM-containing TCR complexes. Cell Commun Signal 2010; 8:5. [PMID: 20298603 PMCID: PMC2848047 DOI: 10.1186/1478-811x-8-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 03/18/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Studying the stoichiometry and intracellular trafficking of the T cell antigen receptor (TCR) is pivotal in understanding its mechanisms of activation. The alphabetaTCR includes the antigen-binding TCRalphabeta heterodimer as well as the signal transducing CD3epsilongamma, CD3epsilondelta and zeta2 subunits. Although the TCR-interacting molecule (TRIM) is also part of the alphabetaTCR complex, it has not been included in most reports so far. RESULTS We used the native antibody-based mobility shift (NAMOS) assay in a first dimension (1D) blue native (BN)-PAGE and a 2D BN-/BN-PAGE to demonstrate that the stoichiometry of the digitonin-solublized TRIM-containing alphabetaTCR is TCRalphabetaCD3epsilon2gammadeltazeta2TRIM2. Smaller alphabetaTCR complexes possess a TCRalphabeta CD3epsilon2gammadeltazeta2 stoichiometry. Complexes of these sizes were detected in T cell lines as well as in primary human and mouse T cells. Stimulating the alphabetaTCR with anti-CD3 antibodies, we demonstrate by confocal laser scanning microscopy that CD3epsilon colocalizes with zeta and both are degraded upon prolonged stimulation, possibly within the lysosomal compartment. In contrast, a substantial fraction of TRIM does not colocalize with zeta. Furthermore, TRIM neither moves to lysosomes nor is degraded. Immunoprecipitation studies and BN-PAGE indicate that TRIM also associates with the gammadeltaTCR. CONCLUSIONS Small alphabetaTCR complexes have a TCRalphabeta CD3epsilon2gammadeltazeta2 stoichiometry; whereas those associated with one TRIM dimer are TCRalphabeta CD3epsilon2gammadeltazeta2TRIM2. TRIM is differentially processed compared to CD3 and zeta subunits after T cell activation and is not degraded. The gammadeltaTCR also associates with TRIM.
Collapse
Affiliation(s)
- Mahima Swamy
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
| | - Gabrielle M Siegers
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
- Cell Therapy Program, Princess Margaret Hospital/Ontario Cancer Institute, 610 University Ave., Toronto, Ontario, M5G 2M9, Canada
| | - Gina J Fiala
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Albertstraße 19A, 79104 Freiburg, Germany
| | - Eszter Molnar
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
| | - Elaine P Dopfer
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
| | - Paul Fisch
- Department of Pathology, University of Freiburg Medical Center, 79110 Freiburg, Germany
| | - Burkhart Schraven
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke-Universität Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany
| | - Wolfgang WA Schamel
- Department of Molecular Immunology, Max Planck-Institute of Immunobiology and Institute for Biology III, Albert Ludwigs University Freiburg, Stübeweg 51, 79108 Freiburg, Germany
| |
Collapse
|
22
|
Analysis of novel phospho-ITAM specific antibodies in a S2 reconstitution system for TCR-CD3 signalling. Immunol Lett 2010; 130:43-50. [PMID: 20005895 DOI: 10.1016/j.imlet.2009.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 12/01/2009] [Accepted: 12/02/2009] [Indexed: 11/23/2022]
Abstract
The T cell antigen receptor (TCR-CD3) complex contains 12 different cytoplasmic tyrosines, each of which is part of an immunoreceptor tyrosine-based activation motif and thus occurs in similar sequence context. Since phosphorylation of individual tyrosines can be correlated with the quality of the T cell response, monitoring their phosphorylation is important. We thus generated novel antibodies against phospho-tyrosines of the TCR-CD3 complex and tested the specificity in a synthetic biology approach. We utilized the Drosophila S2 reconstitution system testing several kinases and stimulation conditions that lead to optimal phosphorylation of the TCR-CD3 subunit zeta. Expressing TCR-CD3 subunits and tyrosine mutants thereof we tested the specificity of the novel antibodies in Western blot and immunopurification experiments. In particular, we generated and characterized the monoclonal antibody EM-26 that specifically recognizes phosphorylation of the membrane proximal tyrosine of zeta (phospho-zetaY1) and antisera raised against the first and the second phospho-tyrosine of CD3epsilon (phospho-epsilonY1 and phospho-epsilonY2).
Collapse
|
23
|
Martínez-Martín N, Risueño RM, Morreale A, Zaldívar I, Fernández-Arenas E, Herranz F, Ortiz AR, Alarcón B. Cooperativity between T cell receptor complexes revealed by conformational mutants of CD3epsilon. Sci Signal 2009; 2:ra43. [PMID: 19671929 DOI: 10.1126/scisignal.2000402] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The CD3epsilon subunit of the T cell receptor (TCR) complex undergoes a conformational change upon ligand binding that is thought to be important for the activation of T cells. To study this process, we built a molecular dynamics model of the transmission of the conformational change within the ectodomains of CD3. The model showed that the CD3 dimers underwent a stiffening effect that was funneled to the base of the CD3epsilon subunit. Mutation of two relevant amino acid residues blocked transmission of the conformational change and the differentiation and activation of T cells. Furthermore, this inhibition occurred even in the presence of excess endogenous CD3epsilon subunits. These results emphasize the importance of the conformational change in CD3epsilon for the activation of T cells and suggest the existence of unforeseen cooperativity between TCR complexes.
Collapse
Affiliation(s)
- Nuria Martínez-Martín
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Bühler P, Molnar E, Dopfer EP, Wolf P, Gierschner D, Wetterauer U, Schamel WW, Elsässer-Beile U. Target-dependent T-cell Activation by Coligation With a PSMA×CD3 Diabody Induces Lysis of Prostate Cancer Cells. J Immunother 2009; 32:565-73. [DOI: 10.1097/cji.0b013e3181a697eb] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
25
|
Lettau M, Pieper J, Janssen O. Nck adapter proteins: functional versatility in T cells. Cell Commun Signal 2009; 7:1. [PMID: 19187548 PMCID: PMC2661883 DOI: 10.1186/1478-811x-7-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 02/02/2009] [Indexed: 01/16/2023] Open
Abstract
Nck is a ubiquitously expressed adapter protein that is almost exclusively built of one SH2 domain and three SH3 domains. The two isoproteins of Nck are functionally redundant in many aspects and differ in only few amino acids that are mostly located in the linker regions between the interaction modules. Nck proteins connect receptor and non-receptor tyrosine kinases to the machinery of actin reorganisation. Thereby, Nck regulates activation-dependent processes during cell polarisation and migration and plays a crucial role in the signal transduction of a variety of receptors including for instance PDGF-, HGF-, VEGF- and Ephrin receptors. In most cases, the SH2 domain mediates binding to the phosphorylated receptor or associated phosphoproteins, while SH3 domain interactions lead to the formation of larger protein complexes. In T lymphocytes, Nck plays a pivotal role in the T cell receptor (TCR)-induced reorganisation of the actin cytoskeleton and the formation of the immunological synapse. However, in this context, two different mechanisms and adapter complexes are discussed. In the first scenario, dependent on an activation-induced conformational change in the CD3epsilon subunits, a direct binding of Nck to components of the TCR/CD3 complex was shown. In the second scenario, Nck is recruited to the TCR complex via phosphorylated Slp76, another central constituent of the membrane proximal activation complex. Over the past years, a large number of putative Nck interactors have been identified in different cellular systems that point to diverse additional functions of the adapter protein, e.g. in the control of gene expression and proliferation.
Collapse
Affiliation(s)
- Marcus Lettau
- University Hospital Schleswig-Holstein Campus Kiel, Institute of Immunology, Molecular Immunology, Arnold-Heller-Str 3, Bldg 17, D-24105 Kiel, Germany.
| | | | | |
Collapse
|