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Kocyła AM, Czogalla A, Wessels I, Rink L, Krężel A. A combined biochemical and cellular approach reveals Zn 2+-dependent hetero- and homodimeric CD4 and Lck assemblies in T cells. Structure 2024; 32:292-303.e7. [PMID: 38157858 DOI: 10.1016/j.str.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/25/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024]
Abstract
The CD4 or CD8 co-receptors' interaction with the protein-tyrosine kinase Lck initiates the tyrosine phosphorylation cascade leading to T cell activation. A critical question is: to what extent are co-receptors and Lck coupled? Our contribution concerns Zn2+, indispensable for CD4- and CD8-Lck formation. We combined biochemical and cellular approaches to show that dynamic fluctuations of free Zn2+ in physiological ranges influence Zn(CD4)2 and Zn(CD4)(Lck) species formation and their ratio, although the same Zn(Cys)2(Cys)2 cores. Moreover, we demonstrated that the affinity of Zn2+ to CD4 and CD4-Lck species differs significantly. Increased intracellular free Zn2+ concentration in T cells causes higher CD4 partitioning in the plasma membrane. We additionally found that CD4 palmitoylation decreases the specificity of CD4-Lck formation in the reconstituted membrane model. Our findings help elucidate co-receptor-Lck coupling stoichiometry and demonstrate that intracellular free Zn2+ has a major role in the interplay between CD4 dimers and CD4-Lck assembly.
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Affiliation(s)
- Anna M Kocyła
- Department of Chemical Biology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Aleksander Czogalla
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland
| | - Inga Wessels
- Institute of Immunology, Faculty of Medicine, RWTH Aachen University, 52074 Aachen, Germany
| | - Lothar Rink
- Institute of Immunology, Faculty of Medicine, RWTH Aachen University, 52074 Aachen, Germany
| | - Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland.
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2
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Van Laethem F, Bhattacharya A, Craveiro M, Lu J, Sun PD, Singer A. MHC-independent αβT cells: Lessons learned about thymic selection and MHC-restriction. Front Immunol 2022; 13:953160. [PMID: 35911724 PMCID: PMC9331304 DOI: 10.3389/fimmu.2022.953160] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/24/2022] [Indexed: 12/02/2022] Open
Abstract
Understanding the generation of an MHC-restricted T cell repertoire is the cornerstone of modern T cell immunology. The unique ability of αβT cells to only recognize peptide antigens presented by MHC molecules but not conformational antigens is referred to as MHC restriction. How MHC restriction is imposed on a very large T cell receptor (TCR) repertoire is still heavily debated. We recently proposed the selection model, which posits that newly re-arranged TCRs can structurally recognize a wide variety of antigens, ranging from peptides presented by MHC molecules to native proteins like cell surface markers. However, on a molecular level, the sequestration of the essential tyrosine kinase Lck by the coreceptors CD4 and CD8 allows only MHC-restricted TCRs to signal. In the absence of Lck sequestration, MHC-independent TCRs can signal and instruct the generation of mature αβT cells that can recognize native protein ligands. The selection model thus explains how only MHC-restricted TCRs can signal and survive thymic selection. In this review, we will discuss the genetic evidence that led to our selection model. We will summarize the selection mechanism and structural properties of MHC-independent TCRs and further discuss the various non-MHC ligands we have identified.
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Affiliation(s)
- François Van Laethem
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- Department of Biological Hematology, Centre Hospitalier Universitaire (CHU) Montpellier, Montpellier, France
- *Correspondence: François Van Laethem, ,
| | - Abhisek Bhattacharya
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Marco Craveiro
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Jinghua Lu
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Peter D. Sun
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Alfred Singer
- Lymphocyte Development Section, Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
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3
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T cell receptor (TCR) signaling in health and disease. Signal Transduct Target Ther 2021; 6:412. [PMID: 34897277 PMCID: PMC8666445 DOI: 10.1038/s41392-021-00823-w] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/18/2022] Open
Abstract
Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.
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4
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Ortiz MA, Mikhailova T, Li X, Porter BA, Bah A, Kotula L. Src family kinases, adaptor proteins and the actin cytoskeleton in epithelial-to-mesenchymal transition. Cell Commun Signal 2021; 19:67. [PMID: 34193161 PMCID: PMC8247114 DOI: 10.1186/s12964-021-00750-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Over a century of scientific inquiry since the discovery of v-SRC but still no final judgement on SRC function. However, a significant body of work has defined Src family kinases as key players in tumor progression, invasion and metastasis in human cancer. With the ever-growing evidence supporting the role of epithelial-mesenchymal transition (EMT) in invasion and metastasis, so does our understanding of the role SFKs play in mediating these processes. Here we describe some key mechanisms through which Src family kinases play critical role in epithelial homeostasis and how their function is essential for the propagation of invasive signals. Video abstract.
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Affiliation(s)
- Maria A Ortiz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Tatiana Mikhailova
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Xiang Li
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Baylee A Porter
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA.,Department of Urology, SUNY Upstate Medical University, Syracuse, USA
| | - Alaji Bah
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA
| | - Leszek Kotula
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, USA. .,Department of Urology, SUNY Upstate Medical University, Syracuse, USA.
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5
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Rajani V, Sengar AS, Salter MW. Src and Fyn regulation of NMDA receptors in health and disease. Neuropharmacology 2021; 193:108615. [PMID: 34051267 DOI: 10.1016/j.neuropharm.2021.108615] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022]
Abstract
The Src family kinases (SFKs) are cytoplasmic non-receptor tyrosine kinases involved in multiple signalling pathways. In the central nervous system (CNS), SFKs are key regulators of N-methyl-d-aspartate receptor (NMDAR) function and major points of convergence for neuronal transduction pathways. Physiological upregulation of NMDAR activity by members of the SFKs, namely Src and Fyn, is crucial for induction of plasticity at Schaffer collateral-CA1 synapses of the hippocampus. Aberrant SFK regulation of NMDARs is implicated in several pathological conditions in the CNS including schizophrenia and pain hypersensitivity. Here, evidence is presented to highlight the current understanding of the intermolecular interactions of SFKs within the NMDAR macromolecular complex, the upstream regulators of SFK activity on NMDAR function and the role Src and Fyn have in synaptic plasticity and metaplasticity. The targeting of SFK protein-protein interactions is discussed as a potential therapeutic strategy to restore signalling activity underlying glutamatergic dysregulation in CNS disease pathophysiology.
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Affiliation(s)
- Vishaal Rajani
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada; Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Ameet S Sengar
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Michael W Salter
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
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6
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Claeys E, Pauwels E, Humblet-Baron S, Provinciael B, Schols D, Waer M, Sprangers B, Vermeire K. Small Molecule Cyclotriazadisulfonamide Abrogates the Upregulation of the Human Receptors CD4 and 4-1BB and Suppresses In Vitro Activation and Proliferation of T Lymphocytes. Front Immunol 2021; 12:650731. [PMID: 33968048 PMCID: PMC8097030 DOI: 10.3389/fimmu.2021.650731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/06/2021] [Indexed: 11/26/2022] Open
Abstract
The small molecule cyclotriazadisulfonamide (CADA) down-modulates the human CD4 receptor, an important factor in T cell activation. Here, we addressed the immunosuppressive potential of CADA using different activation models. CADA inhibited lymphocyte proliferation with low cellular toxicity in a mixed lymphocyte reaction, and when human PBMCs were stimulated with CD3/CD28 beads, phytohemagglutinin or anti-CD3 antibodies. The immunosuppressive effect of CADA involved both CD4+ and CD8+ T cells but was, surprisingly, most prominent in the CD8+ T cell subpopulation where it inhibited cell-mediated lympholysis. Immunosuppression by CADA was characterized by suppressed secretion of various cytokines, and reduced CD25, phosphoSTAT5 and CTPS-1 levels. We discovered a direct down-modulatory effect of CADA on 4-1BB (CD137) expression, a survival factor for activated CD8+ T cells. More specifically, CADA blocked 4‑1BB protein biosynthesis by inhibition of its co-translational translocation into the ER in a signal peptide-dependent way. Taken together, this study demonstrates that CADA, as potent down-modulator of human CD4 and 4‑1BB receptor, has promising immunomodulatory characteristics. This would open up new avenues toward chemotherapeutics that act as selective protein down-modulators to treat various human immunological disorders.
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Affiliation(s)
- Elisa Claeys
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium
| | - Eva Pauwels
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium
| | - Stephanie Humblet-Baron
- Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunology, KU Leuven, Leuven, Belgium
| | - Becky Provinciael
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium
| | - Dominique Schols
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium
| | - Mark Waer
- Department of Microbiology, Immunology and Transplantation, Laboratory of Tracheal Transplantation, KU Leuven, Leuven, Belgium
| | - Ben Sprangers
- Department of Microbiology, Immunology and Transplantation, Laboratory of Molecular Immunology, KU Leuven, Leuven, Belgium
| | - Kurt Vermeire
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy, Rega Institute, Leuven, Belgium
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Mørch AM, Bálint Š, Santos AM, Davis SJ, Dustin ML. Coreceptors and TCR Signaling - the Strong and the Weak of It. Front Cell Dev Biol 2020; 8:597627. [PMID: 33178706 PMCID: PMC7596257 DOI: 10.3389/fcell.2020.597627] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 09/28/2020] [Indexed: 12/02/2022] Open
Abstract
The T-cell coreceptors CD4 and CD8 have well-characterized and essential roles in thymic development, but how they contribute to immune responses in the periphery is unclear. Coreceptors strengthen T-cell responses by many orders of magnitude - beyond a million-fold according to some estimates - but the mechanisms underlying these effects are still debated. T-cell receptor (TCR) triggering is initiated by the binding of the TCR to peptide-loaded major histocompatibility complex (pMHC) molecules on the surfaces of other cells. CD4 and CD8 are the only T-cell proteins that bind to the same pMHC ligand as the TCR, and can directly associate with the TCR-phosphorylating kinase Lck. At least three mechanisms have been proposed to explain how coreceptors so profoundly amplify TCR signaling: (1) the Lck recruitment model and (2) the pseudodimer model, both invoked to explain receptor triggering per se, and (3) two-step coreceptor recruitment to partially triggered TCRs leading to signal amplification. More recently it has been suggested that, in addition to initiating or augmenting TCR signaling, coreceptors effect antigen discrimination. But how can any of this be reconciled with TCR signaling occurring in the absence of CD4 or CD8, and with their interactions with pMHC being among the weakest specific protein-protein interactions ever described? Here, we review each theory of coreceptor function in light of the latest structural, biochemical, and functional data. We conclude that the oldest ideas are probably still the best, i.e., that their weak binding to MHC proteins and efficient association with Lck allow coreceptors to amplify weak incipient triggering of the TCR, without comprising TCR specificity.
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Affiliation(s)
- Alexander M. Mørch
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Štefan Bálint
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Simon J. Davis
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Michael L. Dustin
- The Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
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8
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Spassov DS, Ruiz-Saenz A, Piple A, Moasser MM. A Dimerization Function in the Intrinsically Disordered N-Terminal Region of Src. Cell Rep 2019; 25:449-463.e4. [PMID: 30304684 PMCID: PMC6226010 DOI: 10.1016/j.celrep.2018.09.035] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 07/09/2018] [Accepted: 09/12/2018] [Indexed: 01/30/2023] Open
Abstract
The mode of regulation of Src kinases has been elucidated by crystallographic studies identifying conserved structured protein modules involved in an orderly set of intramolecular associations and ligand interactions. Despite these detailed insights, much of the complex behavior and diversity in the Src family remains unexplained. A key missing piece is the function of the unstructured N-terminal region. We report here the function of the N-terminal region in binding within a hydrophobic pocket in the kinase domain of a dimerization partner. Dimerization substantially enhances autophosphorylation and phosphorylation of selected substrates, and interfering with dimerization is disruptive to these functions. Dimerization and Y419 phosphorylation are codependent events creating a bistable switch. Given the versatility inherent in this intrinsically disordered region, its multisite phosphorylations, and its divergence within the family, the unique domain likely functions as a central signaling hub overseeing much of the activities and unique functions of Src family kinases. Spassov et al. report that Src exists in cells and functions as a dimer and that dimerization and autophosphorylation are codependent events. Through a comprehensive structure-function analysis, they show that the dimer is an asymmetric dimer held through the interaction of the myristoylated N-terminal unique domain of one partner with a hydrophobic pocket in the kinase domain of another.
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Affiliation(s)
- Danislav S Spassov
- Department of Medicine, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ana Ruiz-Saenz
- Department of Medicine, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Amit Piple
- Department of Medicine, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Mark M Moasser
- Department of Medicine, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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9
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Wan R, Wu J, Ouyang M, Lei L, Wei J, Peng Q, Harrison R, Wu Y, Cheng B, Li K, Zhu C, Tang L, Wang Y, Lu S. Biophysical basis underlying dynamic Lck activation visualized by ZapLck FRET biosensor. SCIENCE ADVANCES 2019; 5:eaau2001. [PMID: 31223643 PMCID: PMC6584686 DOI: 10.1126/sciadv.aau2001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/15/2019] [Indexed: 05/25/2023]
Abstract
Lck plays crucial roles in TCR signaling. We developed a new and sensitive FRET biosensor (ZapLck) to visualize Lck kinase activity with high spatiotemporal resolutions in live cells. ZapLck revealed that 62% of Lck signal was preactivated in T-cells. In Lck-deficient JCam T-cells, Lck preactivation was abolished, which can be restored to 51% by reconstitution with wild-type Lck (LckWT) but not a putatively inactive mutant LckY394F. LckWT also showed a stronger basal Lck-Lck interaction and a slower diffusion rate than LckY394F. Interestingly, aggregation of TCR receptors by antibodies in JCam cells led to a strong activation of reconstituted LckY394F similar to LckWT. Both activated LckY394F and LckWT diffused more slowly and displayed increased Lck-Lck interaction at a similar level. Therefore, these results suggest that a phosphorylatable Y394 is necessary for the basal-level interaction and preactivation of LckWT, while antibody-induced TCR aggregation can trigger the full activation of LckY394F.
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Affiliation(s)
- Rongxue Wan
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenny Wu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mingxing Ouyang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lei Lei
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jiaming Wei
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Qin Peng
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reed Harrison
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yiqian Wu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Binbin Cheng
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaitao Li
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Cheng Zhu
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Liling Tang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044, China
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shaoying Lu
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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10
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Zeidan N, Damen H, Roy DC, Dave VP. Critical Role for TCR Signal Strength and MHC Specificity in ThPOK-Induced CD4 Helper Lineage Choice. THE JOURNAL OF IMMUNOLOGY 2019; 202:3211-3225. [PMID: 31036767 DOI: 10.4049/jimmunol.1801464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/26/2019] [Indexed: 01/08/2023]
Abstract
Sustained TCR signaling is critical for ThPOK induction in MHC class II (MHCII)-signaled thymocytes leading to the CD4 helper lineage commitment. ThPOK suppresses the cytotoxic program in the signaled thymocytes and is shown to be necessary and sufficient for the CD4 helper lineage choice. Accordingly, loss and gain of ThPOK function redirects MHCII- and MHC class I (MHCI)-signaled thymocytes into the CD8 cytotoxic and CD4 helper lineage, respectively. However, the impact of a defined ThPOK level on the CD4 helper lineage choice of MHCII- and MHCI-specific thymocytes and the role of TCR signaling in this process is not evaluated. Equally, it is not clear if suppression of the cytotoxic program by ThPOK is sufficient in redirecting MHCI-restricted thymocytes into the CD4 helper lineage. In this study, we have investigated CD8 to CD4 helper lineage redirection in three independent ThPOK overexpressing transgenic mouse lines. Our analysis shows that one of the transgenic lines, despite overexpressing ThPOK compared with wild-type CD4 mature T cells and compromising cytotoxic program, failed to redirect all MHCI-signaled thymocytes into the CD4 helper lineage, resulting in the continued presence of CD8+ mature T cells and the generation of a large number of double negative mature T cells. Critically, the same ThPOK transgene completely restored the CD4 helper lineage commitment of MHCII-specific Thpok -/- thymocytes. Importantly, augmenting TCR signaling significantly enhanced the ThPOK-mediated CD4 helper lineage choice of MHCI-specific thymocytes but was still substantially less efficient than that of MHCII-specific thymocytes expressing the same amount of ThPOK. Together, these data suggest that the ThPOK-induced CD4 helper lineage commitment is strongly influenced by TCR signal strength and MHC specificity of developing thymocytes.
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Affiliation(s)
- Nabil Zeidan
- Département d'Immunologie-Oncologie, Centre de Recherche Hôpital Maisonneuve-Rosemont, Montreal, Quebec H1T 2M4, Canada.,Département de Microbiologie, Immunologie et Infectiologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada; and
| | - Hassan Damen
- Département d'Immunologie-Oncologie, Centre de Recherche Hôpital Maisonneuve-Rosemont, Montreal, Quebec H1T 2M4, Canada
| | - Denis-Claude Roy
- Département d'Immunologie-Oncologie, Centre de Recherche Hôpital Maisonneuve-Rosemont, Montreal, Quebec H1T 2M4, Canada.,Department of Medicine, University of Montreal, Montreal, Quebec H3C 3J7, Canada
| | - Vibhuti P Dave
- Département d'Immunologie-Oncologie, Centre de Recherche Hôpital Maisonneuve-Rosemont, Montreal, Quebec H1T 2M4, Canada; .,Département de Microbiologie, Immunologie et Infectiologie, Université de Montréal, Montreal, Quebec H3C 3J7, Canada; and
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11
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Kimura MY, Thomas J, Tai X, Guinter TI, Shinzawa M, Etzensperger R, Li Z, Love P, Nakayama T, Singer A. Timing and duration of MHC I positive selection signals are adjusted in the thymus to prevent lineage errors. Nat Immunol 2016; 17:1415-1423. [PMID: 27668801 DOI: 10.1038/ni.3560] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 08/17/2016] [Indexed: 12/12/2022]
Abstract
Major histocompatibility complex class I (MHC I) positive selection of CD8+ T cells in the thymus requires that T cell antigen receptor (TCR) signaling end in time for cytokines to induce Runx3d, the CD8-lineage transcription factor. We examined the time required for these events and found that the overall duration of positive selection was similar for all CD8+ thymocytes in mice, despite markedly different TCR signaling times. Notably, prolonged TCR signaling times were counter-balanced by accelerated Runx3d induction by cytokines and accelerated differentiation into CD8+ T cells. Consequently, lineage errors did not occur except when MHC I-TCR signaling was so prolonged that the CD4-lineage-specifying transcription factor ThPOK was expressed, preventing Runx3d induction. Thus, our results identify a compensatory signaling mechanism that prevents lineage-fate errors by dynamically modulating Runx3d induction rates during MHC I positive selection.
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Affiliation(s)
- Motoko Y Kimura
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Julien Thomas
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Xuguang Tai
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Terry I Guinter
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Miho Shinzawa
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Ruth Etzensperger
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
| | - Zhenhu Li
- Laboratory of Mammalian Genes and Development, Eunice Kennedy Schriver National Institute of Child Health and Human Development, US National Institutes of Health, Bethesda, Maryland, USA
| | - Paul Love
- Laboratory of Mammalian Genes and Development, Eunice Kennedy Schriver National Institute of Child Health and Human Development, US National Institutes of Health, Bethesda, Maryland, USA
| | | | - Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, US National Institutes of Health, Bethesda, Maryland, USA
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12
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Schmidt EP, Kuebler WM, Lee WL, Downey GP. Adhesion Molecules: Master Controllers of the Circulatory System. Compr Physiol 2016; 6:945-73. [PMID: 27065171 DOI: 10.1002/cphy.c150020] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This manuscript will review our current understanding of cellular adhesion molecules (CAMs) relevant to the circulatory system, their physiological role in control of vascular homeostasis, innate and adaptive immune responses, and their importance in pathophysiological (disease) processes such as acute lung injury, atherosclerosis, and pulmonary hypertension. This is a complex and rapidly changing area of research that is incompletely understood. By design, we will begin with a brief overview of the structure and classification of the major groups of adhesion molecules and their physiological functions including cellular adhesion and signaling. The role of specific CAMs in the process of platelet aggregation and hemostasis and leukocyte adhesion and transendothelial migration will be reviewed as examples of the complex and cooperative interplay between CAMs during physiological and pathophysiological processes. The role of the endothelial glycocalyx and the glycobiology of this complex system related to inflammatory states such as sepsis will be reviewed. We will then focus on the role of adhesion molecules in the pathogenesis of specific disease processes involving the lungs and cardiovascular system. The potential of targeting adhesion molecules in the treatment of immune and inflammatory diseases will be highlighted in the relevant sections throughout the manuscript.
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Affiliation(s)
- Eric P Schmidt
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado, USA
| | - Wolfgang M Kuebler
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
- Departments of Surgery and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Warren L Lee
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
- Division of Respirology and the Interdepartmental Division of Critical Care Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Gregory P Downey
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado, USA
- Division of Pulmonary, Critical Care, and Sleep Medicine, Departments of Medicine, Pediatrics, and Biomedical Research, National Jewish Health, Denver, Colorado, USA
- Departments of Medicine, and Immunology and Microbiology, University of Colorado, Aurora, Colorado, USA
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13
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Parrish HL, Glassman CR, Keenen MM, Deshpande NR, Bronnimann MP, Kuhns MS. A Transmembrane Domain GGxxG Motif in CD4 Contributes to Its Lck-Independent Function but Does Not Mediate CD4 Dimerization. PLoS One 2015; 10:e0132333. [PMID: 26147390 PMCID: PMC4493003 DOI: 10.1371/journal.pone.0132333] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 06/14/2015] [Indexed: 12/24/2022] Open
Abstract
CD4 interactions with class II major histocompatibility complex (MHC) molecules are essential for CD4+ T cell development, activation, and effector functions. While its association with p56lck (Lck), a Src kinase, is important for these functions CD4 also has an Lck-independent role in TCR signaling that is incompletely understood. Here, we identify a conserved GGxxG motif in the CD4 transmembrane domain that is related to the previously described GxxxG motifs of other proteins and predicted to form a flat glycine patch in a transmembrane helix. In other proteins, these patches have been reported to mediate dimerization of transmembrane domains. Here we show that introducing bulky side-chains into this patch (GGxxG to GVxxL) impairs the Lck-independent role of CD4 in T cell activation upon TCR engagement of agonist and weak agonist stimulation. However, using Forster’s Resonance Energy Transfer (FRET), we saw no evidence that these mutations decreased CD4 dimerization either in the unliganded state or upon engagement of pMHC concomitantly with the TCR. This suggests that the CD4 transmembrane domain is either mediating interactions with an unidentified partner, or mediating some other function such as membrane domain localization that is important for its role in T cell activation.
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Affiliation(s)
- Heather L. Parrish
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Caleb R. Glassman
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Madeline M. Keenen
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Neha R. Deshpande
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
- The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Matthew P. Bronnimann
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
| | - Michael S. Kuhns
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
- The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
- The BIO-5 Institute, The University of Arizona College of Medicine, Tucson, Arizona, United States of America
- * E-mail:
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The coreceptor CD4 is expressed in distinct nanoclusters and does not colocalize with T-cell receptor and active protein tyrosine kinase p56lck. Proc Natl Acad Sci U S A 2015; 112:E1604-13. [PMID: 25829544 DOI: 10.1073/pnas.1503532112] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
CD4 molecules on the surface of T lymphocytes greatly augment the sensitivity and activation process of these cells, but how it functions is not fully understood. Here we studied the spatial organization of CD4, and its relationship to T-cell antigen receptor (TCR) and the active form of Src kinase p56lck (Lck) using single and dual-color photoactivated localization microscopy (PALM) and direct stochastic optical reconstruction microscopy (dSTORM). In nonactivated T cells, CD4 molecules are clustered in small protein islands, as are TCR and Lck. By dual-color imaging, we find that CD4, TCR, and Lck are localized in their separate clusters with limited interactions in the interfaces between them. Upon T-cell activation, the TCR and CD4 begin clustering together, developing into microclusters, and undergo a larger scale redistribution to form supramolecluar activation clusters (SMACs). CD4 and Lck localize in the inner TCR region of the SMAC, but this redistribution of disparate cluster structures results in enhanced segregation from each other. In nonactivated cells these preclustered structures and the limited interactions between them may serve to limit spontaneous and random activation events. However, the small sizes of these island structures also ensure large interfacial surfaces for potential interactions and signal amplification when activation is initiated. In the later activation stages, the increasingly larger clusters and their segregation from each other reduce the interfacial surfaces and could have a dampening effect. These highly differentiated spatial distributions of TCR, CD4, and Lck and their changes during activation suggest that there is a more complex hierarchy than previously thought.
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15
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Komal P, Gudavicius G, Nelson CJ, Nashmi R. T-cell receptor activation decreases excitability of cortical interneurons by inhibiting α7 nicotinic receptors. J Neurosci 2014; 34:22-35. [PMID: 24381265 PMCID: PMC6608162 DOI: 10.1523/jneurosci.2093-13.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 11/21/2022] Open
Abstract
Many proteins in the immune system are also expressed in the brain. One such class of immune proteins are T-cell receptors (TCRs), whose functions in T lymphocytes in adaptive immunity are well characterized. In the brain, TCRs are confined to neocortical neurons, but their functional role has not been determined. In mouse layer 1 neocortical neurons, TCR activation inhibited α7 nicotinic currents. TCRs modulated α7 currents via tyrosine phosphorylation of α7 nicotinic receptors (nAChRs) through src tyrosine kinases because eliminating lck kinase expression, coexpressing fyn kinase dead, or mutating tyrosine to alanine in α7 blocked the effect of TCR activation. We found that TCR stimulation decreased surface α7 nAChRs and reduced single-channel conductance. These results reveal that TCRs play a major role in the modulation of cholinergic neurotransmission in the brain mediated by α7 nAChRs and that this has a profound effect on regulating neuronal excitability.
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Affiliation(s)
| | - Geoff Gudavicius
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3N5, Canada
| | - Christopher J. Nelson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3N5, Canada
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16
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Van Laethem F, Tikhonova AN, Pobezinsky LA, Tai X, Kimura MY, Le Saout C, Guinter TI, Adams A, Sharrow SO, Bernhardt G, Feigenbaum L, Singer A. Lck availability during thymic selection determines the recognition specificity of the T cell repertoire. Cell 2013; 154:1326-41. [PMID: 24034254 DOI: 10.1016/j.cell.2013.08.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/02/2013] [Accepted: 08/08/2013] [Indexed: 11/16/2022]
Abstract
Thymic selection requires signaling by the protein tyrosine kinase Lck to generate T cells expressing αβ T cell antigen receptors (TCR). For reasons not understood, the thymus selects only αβTCR that are restricted by major histocompatibility complex (MHC)-encoded determinants. Here, we report that Lck proteins that were coreceptor associated promoted thymic selection of conventionally MHC-restricted TCR, but Lck proteins that were coreceptor free promoted thymic selection of MHC-independent TCR. Transgenic TCR with MHC-independent specificity for CD155 utilized coreceptor-free Lck to signal thymic selection in the absence of MHC, unlike any transgenic TCR previously described. Thus, the thymus can select either MHC-restricted or MHC-independent αβTCR depending on whether Lck is coreceptor associated or coreceptor free. We conclude that the intracellular state of Lck determines the specificity of thymic selection and that Lck association with coreceptor proteins during thymic selection is the mechanism by which MHC restriction is imposed on a randomly generated αβTCR repertoire.
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Affiliation(s)
- François Van Laethem
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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17
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Abstract
Tyrosine phosphorylation is one of the key covalent modifications that occur in multicellular organisms. Since its discovery more than 30 years ago, tyrosine phosphorylation has come to be understood as a fundamentally important mechanism of signal transduction and regulation in all eukaryotic cells. The tyrosine kinase Lck (lymphocyte-specific protein tyrosine kinase) plays a crucial role in the T-cell response by transducing early activation signals triggered by TCR (T-cell receptor) engagement. These signals result in the phosphorylation of immunoreceptor tyrosine-based activation motifs present within the cytosolic tails of the TCR-associated CD3 subunits that, once phosphorylated, serve as scaffolds for the assembly of a large supramolecular signalling complex responsible for T-cell activation. The existence of membrane nano- or micro-domains or rafts as specialized platforms for protein transport and cell signalling has been proposed. The present review discusses the signals that target Lck to membrane rafts and the importance of these specialized membranes in the transport of Lck to the plasma membrane, the regulation of Lck activity and the phosphorylation of the TCR.
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18
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Choudhuri K, Dustin ML. Signaling microdomains in T cells. FEBS Lett 2010; 584:4823-31. [PMID: 20965175 DOI: 10.1016/j.febslet.2010.10.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 01/22/2023]
Abstract
Sub-micron scale signaling domains induced in the plasma membrane of cells are thought to play important roles in signal transduction. In T cells, agonist MHC-peptide complexes induce small diffraction-limited domains enriched in T cell receptor (TCR) and signaling molecules. These microclusters serve as transient platforms for signal initiation and are required for sustained signaling in T cells, although each microcluster functions for only a couple of minutes. How they are formed, and what mechanisms promote and regulate signaling within TCR microclusters is largely unknown, although it is clear that TCR engagement and dynamic reorganization of cortical actin are involved. Here, we review current understanding of signaling within microclusters in T cells, and speculate on how these structures may form, initiate biochemical signals, and serve as sites of both signal integration and amplification, while also facilitating appropriate termination of TCR and related signaling.
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Affiliation(s)
- Kaushik Choudhuri
- Helen L and Martin S Kimmel Center for Biology and Medicine of the Skirball Institute of Biomolecular Medicine, New York, NY 10016, USA
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19
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Mislocalization of Lck impairs thymocyte differentiation and can promote development of thymomas. Blood 2010; 117:108-17. [PMID: 20876849 DOI: 10.1182/blood-2010-03-277160] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
T-cell development is critically dependent on the activities of the Src-family kinases p56(lck) and p59(fyn). While Lck plays a dominant role in the initiation of T-cell receptor (TCR) signaling and in thymocyte differentiation, Fyn plays a more subtle regulatory role. We sought to determine the role of intracellular localization in the differing functions of Lck and Fyn in T cells. By generating transgenic mice that express chimeric Lck-Fyn proteins, we showed that the N-terminal unique domain determines the intracellular localization and function of Lck in pre-TCR and mature αβTCR signaling in vivo. Furthermore, coexpression of a "domain-swap" Lck protein containing the Fyn unique domain with an inducible Lck transgene resulted in the development of thymomas. In contrast to previous reports of Lck-driven thymomas, tumor development was dependent on either pre-TCR or mature TCR signals, and was completely ablated when mice were crossed to a recombination activating gene 1 (Rag1)-deficient background. These data provide a mechanistic basis for the differing roles of Lck and Fyn in T-cell development, and show that intracellular localization as determined by the N-terminal unique domains is critical for Src-family kinase function in vivo.
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20
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Lefebvre DC, Lai JC, Maeshima N, Ford JL, Wong AS, Cross JL, Johnson P. CD44 interacts directly with Lck in a zinc-dependent manner. Mol Immunol 2010; 47:1882-9. [DOI: 10.1016/j.molimm.2010.03.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 03/20/2010] [Accepted: 03/23/2010] [Indexed: 01/13/2023]
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21
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Liew CY, Ma XH, Liu X, Yap CW. SVM Model for Virtual Screening of Lck Inhibitors. J Chem Inf Model 2009; 49:877-85. [DOI: 10.1021/ci800387z] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Chin Y. Liew
- Pharmaceutical Data Exploration Laboratory, Department of Pharmacy, National University of Singapore, and Bioinformatics and Drug Design Group, Department of Pharmacy, National University of Singapore
| | - Xiao H. Ma
- Pharmaceutical Data Exploration Laboratory, Department of Pharmacy, National University of Singapore, and Bioinformatics and Drug Design Group, Department of Pharmacy, National University of Singapore
| | - Xianghui Liu
- Pharmaceutical Data Exploration Laboratory, Department of Pharmacy, National University of Singapore, and Bioinformatics and Drug Design Group, Department of Pharmacy, National University of Singapore
| | - Chun W. Yap
- Pharmaceutical Data Exploration Laboratory, Department of Pharmacy, National University of Singapore, and Bioinformatics and Drug Design Group, Department of Pharmacy, National University of Singapore
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22
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Palmer E, Naeher D. Affinity threshold for thymic selection through a T-cell receptor–co-receptor zipper. Nat Rev Immunol 2009; 9:207-13. [DOI: 10.1038/nri2469] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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23
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Kao H, Lin J, Littman DR, Shaw AS, Allen PM. Regulated movement of CD4 in and out of the immunological synapse. THE JOURNAL OF IMMUNOLOGY 2009; 181:8248-57. [PMID: 19050241 DOI: 10.4049/jimmunol.181.12.8248] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The mechanism underlying the transient accumulation of CD4 at the immunological synapse (IS) and its significance for T cell activation are not understood. To investigate these issues, we mutated a serine phosphorylation site (S408) in the cytoplasmic tail of murine CD4. Preventing phosphorylation of S408 did not block CD4 recruitment to the IS; rather, it blocked the ability of CD4 to leave the IS. Surprisingly, enhanced and prolonged CD4 accumulation at the supramolecular activation cluster in the contact area had no functional consequence for T cell activation, cytokine production, or proliferation. Protein kinase C theta (PKCtheta)-deficient T cells also displayed enhanced and prolonged accumulation of wild-type CD4 at the IS, indicating that theta is the critical PKC isoform involved in CD4 movement. These findings suggest a model wherein recruitment of CD4 to the IS allows its phosphorylation by PKCtheta and subsequent removal from the IS. Thus, an important role for PKCtheta in T cell activation involves its recruitment to the IS, where it phosphorylates specific substrates that help to maintain the dynamism of protein turnover at the IS.
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Affiliation(s)
- Henry Kao
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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24
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Singer A, Adoro S, Park JH. Lineage fate and intense debate: myths, models and mechanisms of CD4- versus CD8-lineage choice. Nat Rev Immunol 2008; 8:788-801. [PMID: 18802443 DOI: 10.1038/nri2416] [Citation(s) in RCA: 347] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Following successful gene rearrangement at alphabeta T-cell receptor (TCR) loci, developing thymocytes express both CD4 and CD8 co-receptors and undergo a life-or-death selection event, which is known as positive selection, to identify cells that express TCRs with potentially useful ligand specificities. Positively selected thymocytes must then differentiate into either CD4(+) helper T cells or CD8(+) cytotoxic T cells, a crucial decision known as CD4/CD8-lineage choice. In this Review, we summarize recent advances in our understanding of the cellular and molecular events involved in lineage-fate decision and discuss them in the context of the major models of CD4/CD8-lineage choice.
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Affiliation(s)
- Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA.
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25
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Awale M, Mohan CG. Molecular docking guided 3D-QSAR CoMFA analysis of N-4-Pyrimidinyl-1H-indazol-4-amine inhibitors of leukocyte-specific protein tyrosine kinase. J Mol Model 2008; 14:937-47. [PMID: 18626671 DOI: 10.1007/s00894-008-0334-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
Abstract
Inhibition of leukocyte-specific protein tyrosine kinase (Lck) activity offers one of the approaches for the treatment of T-cell mediated inflammatory disorders including rheumatoid arthritis, transplant rejection and inflammatory bowel disease. To explore the relationship between the structures of the N-4 Pyrimidinyl-1H-indazol-4-amines and their Lck inhibition, 3D-QSAR study using CoMFA analysis have been performed on a dataset of 42 molecules. The bioactive conformation of the template molecule, selected as the most potent molecule 23 from the series was obtained by performing molecular docking at the ATP binding site of Lck, which is then used to build the rest of the molecules in the series. The constructed CoMFA model is robust with r(2)(cv) of 0.603 and conventional r2 of 0.983. The predictive power of the developed model was obtained using a test set of 10 molecules, giving predictive correlation coefficient of 0.921. CoMFA contour analysis was performed to obtain useful information about the structural requirements for the Lck inhibitors which could be utilized in its future design.
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Affiliation(s)
- Mahendra Awale
- Centre for Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, 160 062, Punjab, India
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26
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O'Shea JJ, Johnston JA, Kehrl J, Koretzky G, Samelson LE. Key molecules involved in receptor-mediated lymphocyte activation. ACTA ACUST UNITED AC 2008; Chapter 11:Unit 11.9A. [PMID: 18432708 DOI: 10.1002/0471142735.im1109as44] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This unit, along with Unit 11.9B, provides a summary of our current knowledge about various signaling pathways critical to the function of immune cells. Here, our understanding of T cell receptor (TCR)- and B cell receptor (BCR)-mediated signaling is summarized. A schematic representation of immunologically relevant cytokine receptors and the Janus Family Kinases (JAKs) that is activated through these receptors is provided, along with details about molecules involved in interleukin 2 mediated signal transduction.
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Affiliation(s)
- J J O'Shea
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, Maryland, USA
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27
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Epstein-Barr virus latent membrane protein 2A preferentially signals through the Src family kinase Lyn. J Virol 2008; 82:8520-8. [PMID: 18579586 DOI: 10.1128/jvi.00843-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Latent membrane protein 2A (LMP2A) is a viral protein expressed during Epstein-Barr virus (EBV) latency in EBV-infected B cells both in cell culture and in vivo. LMP2A has important roles in modulating B-cell receptor signal transduction and provides survival and developmental signals to B cells in vivo. Although Lyn has been shown to be important in mediating LMP2A signaling, it is still unclear if Lyn is used preferentially or if LMP2A associates promiscuously with other Src family kinase (SFK) members. To investigate the role of various SFKs in LMP2A signaling, we crossed LMP2A transgenic mice (TgE) with Lyn(-/-), Fyn(-/-), or Blk(-/-) mice. TgE Lyn(-/-) mice had a larger immunoglobulin M (IgM)-positive B-cell population than TgE mice, suggesting that the absence of Lyn prevents LMP2A from delivering survival and developmental signals to the B cells. Both TgE Fyn(-/-) and TgE Blk(-/-) mice have an IgM-negative population of splenic B cells, similar to the TgE mice. LMP2A was also transiently transfected into the human EBV-negative B-cell line BJAB to determine which SFK members associate with LMP2A. Lyn was detected in LMP2A immunoprecipitates, whereas Fyn was not. Both Lyn and Fyn were able to bind to an LMP2A mutant which contained a sequence shown previously to bind tightly to the SH2 domain of multiple SFK members. From these results, we conclude that LMP2A preferentially associates with and signals through Lyn compared to its association with other SFKs. This preferential association is due in part to the SH2 domain of Lyn associating with LMP2A.
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28
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Cooper JA, Qian H. A mechanism for SRC kinase-dependent signaling by noncatalytic receptors. Biochemistry 2008; 47:5681-5688. [PMID: 18444664 DOI: 10.1021/bi8003044] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A fundamental issue in cell biology is how signals are transmitted across membranes. A variety of transmembrane receptors, including multichain immune recognition receptors, lack catalytic activity and require Src family kinases (SFKs) for signal transduction. However, many receptors only bind and activate SFKs after ligand-induced receptor dimerization. This presents a conundrum: How do SFKs sense the dimerization of receptors to which they are not already bound? Most proposals for resolving this enigma invoke additional players, such as lipid rafts or receptor conformational changes. Here we used simple thermodynamics to show that SFK activation is a natural outcome of clustering of receptors with SFK phosphorylation sites, provided that there is phosphorylation-dependent receptor-SFK association and an SFK bound to one receptor can phosphorylate the second receptor or its associated SFK in a dimer. A simple system of receptor, SFK, and an unregulated protein tyrosine phosphatase (PTP) can account for ligand-induced changes in phosphorylation observed in cells. We suggest that a core signaling system comprising a receptor with SFK phosphorylation sites, an SFK, and an unregulated PTP provides a robust mechanism for transmembrane signal transduction. Other events that regulate signaling in specific cases may have evolved for fine-tuning of this basic mechanism.
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Affiliation(s)
- Jonathan A Cooper
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Hong Qian
- Department of Applied Mathematics, University of Washington, Seattle, Washington 98195
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29
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Huse M, Klein LO, Girvin AT, Faraj JM, Li QJ, Kuhns MS, Davis MM. Spatial and temporal dynamics of T cell receptor signaling with a photoactivatable agonist. Immunity 2007; 27:76-88. [PMID: 17629516 DOI: 10.1016/j.immuni.2007.05.017] [Citation(s) in RCA: 192] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 04/26/2007] [Accepted: 05/15/2007] [Indexed: 11/24/2022]
Abstract
The precise timing of signals downstream of the T cell receptor (TCR) is poorly understood. To address this problem, we prepared major histocompatibility complexes containing an antigenic peptide that is biologically inert until exposed to ultraviolet (UV) light. UV irradiation of these complexes in contact with cognate T cells enabled the high-resolution temporal analysis of signaling. Phosphorylation of the LAT adaptor molecule was observed in 4 s, and diacylglycerol production and calcium flux was observed in 6-7 s. TCR activation also induced cytoskeletal polarization within 2 min. Antibody blockade of CD4 reduced the intensity of LAT phosphorylation and the speed of calcium flux. Furthermore, strong desensitization of diacylglycerol production, but not LAT phosphorylation, occurred shortly after TCR activation, suggesting that different molecular events play distinct signal-processing roles. These results establish the speed and localization of early signaling steps, and have important implications regarding the overall structure of the network.
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Affiliation(s)
- Morgan Huse
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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30
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Fragoso RC, Pyarajan S, Irie HY, Burakoff SJ. A CD8/Lck transgene is able to drive thymocyte differentiation. THE JOURNAL OF IMMUNOLOGY 2006; 177:6007-17. [PMID: 17056525 DOI: 10.4049/jimmunol.177.9.6007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Efficient development of thymocytes requires participation of a CD8 or CD4 coreceptor in the TCR:MHC interaction. Both CD8 and CD4 coreceptor cytoplasmic domains associate with Lck. In this study, we attempted to delineate the role of CD8alpha-associated Lck in driving CD8 single positive (SP) thymocyte development. We used a chimeric molecule encoding the extracellular and transmembrane domains of CD8alpha fused to full-length Lck. In mice deficient for CD8alpha and transgenic for 2C, a MHC class I-restricted TCR, robust reconstitution of CD8 SP thymocytes occurred both centrally and peripherally. The reconstituted CD8 SP population was phenotypically and functionally comparable to 2C wild-type counterparts expressing endogenous CD8alpha. A CD8alpha/Lck kinase-dead chimera also resulted in reconstitution of CD8 SP thymocytes. Our results suggest that CD8alpha-associated Lck is sufficient to drive CD8 SP thymocyte development. Furthermore, this CD8 SP development may not necessarily depend on Lck kinase activity.
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Affiliation(s)
- Ruben C Fragoso
- Dana-Farber Cancer Institute, Department of Pediatric Oncology, Harvard Medical School, Boston, MA 02115, USA
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Basmaciogullari S, Pacheco B, Bour S, Sodroski J. Specific interaction of CXCR4 with CD4 and CD8alpha: functional analysis of the CD4/CXCR4 interaction in the context of HIV-1 envelope glycoprotein-mediated membrane fusion. Virology 2006; 353:52-67. [PMID: 16808956 DOI: 10.1016/j.virol.2006.05.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Revised: 03/23/2006] [Accepted: 05/24/2006] [Indexed: 11/18/2022]
Abstract
We investigated possible interactions between HIV-1 receptor (CD4) and the main coreceptors CXCR4 and CCR5. We found that CD4 and CXCR4 coexpressed in 293T cells form a complex that can be immunoprecipitated with antibodies directed against the extracellular domain of either protein. Mutagenesis revealed that the CD4/CXCR4 interaction maps to two previously uncharacterized basic motifs in the cytoplasmic domain of CD4. HIV-1 envelope glycoprotein-mediated membrane fusion was found to be independent of the ability of CD4 and CXCR4 to interact, whether fusion was studied in a virus-cell or a cell-cell model. However, this interaction might explain the adaptation of HIV-1 to CXCR4 as an alternative to CCR5. We found that CXCR4 also interacts with the cytoplasmic domain of CD8alpha in a way that is similar to the CD4/CXCR4 interaction. The CD4/CXCR4 and CD8alpha/CXCR4 interactions may thus be involved in cellular signaling pathways shared by the CD4 and CD8alpha molecules.
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32
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Mason LH, Willette-Brown J, Taylor LS, McVicar DW. Regulation of Ly49D/DAP12 Signal Transduction by Src-Family Kinases and CD45. THE JOURNAL OF IMMUNOLOGY 2006; 176:6615-23. [PMID: 16709819 DOI: 10.4049/jimmunol.176.11.6615] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activating, DAP12-coupled members of the Ly-49 family of NK cell receptors help control viral infections in mice. However, the kinases and/or phosphatases mediating tyrosine phosphorylation of Ly-49D-associated DAP12 have not been elucidated. In this study, we show for the first time that Src family tyrosine kinases are physically and functionally associated with Ly-49D/DAP12 signaling in murine NK cells. Specifically, we demonstrate the following: 1) inhibition of Src family kinases suppresses DAP12 phosphorylation and downstream DAP12 signals; 2) both Fyn and Lck are capable of phosphorylating DAP12; and 3) both kinases coimmunoprecipitate with the Ly-49D/DAP12 complex in NK cells. Although we detect enhanced phosphorylation of Fyn upon Ly-49D cross-linking in NK cells, Ly-49D-mediated events in both Fyn-/- and Fyn/Lck-/- mice appear normal, reinforcing the theme of redundancy in the ability of Src family kinases to initiate activation events. In contrast to disruption of specific Src family enzymes, Ly-49D/DAP12-mediated calcium mobilization and cytokine production by CD45 null NK cells are defective. Although others have ascribed the effects of CD45 mutation solely on the suppression of Src family activity, we demonstrate in this study that DAP12 is hyperphosphorylated in CD45 null NK cells, resulting in uncoordinated tyrosine-mediated signaling upon Ly-49D ligation. Therefore, although our data are consistent with a Src kinase activity proximally within DAP12 signaling, DAP12 also appears to be a substrate of CD45, suggesting a more complex role for this phosphatase than has been reported previously.
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MESH Headings
- Adaptor Proteins, Signal Transducing/antagonists & inhibitors
- Adaptor Proteins, Signal Transducing/metabolism
- Adaptor Proteins, Signal Transducing/physiology
- Animals
- Antibodies, Monoclonal/metabolism
- Antigens, Ly/immunology
- Antigens, Ly/metabolism
- Antigens, Ly/physiology
- Cell Line
- Cells, Cultured
- Cross-Linking Reagents/metabolism
- Cytotoxicity Tests, Immunologic
- Down-Regulation/immunology
- Humans
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/physiology
- Killer Cells, Natural/enzymology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lectins, C-Type/immunology
- Lectins, C-Type/metabolism
- Lectins, C-Type/physiology
- Leukocyte Common Antigens/genetics
- Leukocyte Common Antigens/physiology
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NK Cell Lectin-Like Receptor Subfamily A
- Phosphorylation
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/physiology
- Proto-Oncogene Proteins c-fyn/deficiency
- Proto-Oncogene Proteins c-fyn/genetics
- Proto-Oncogene Proteins c-fyn/physiology
- Pyrimidines/pharmacology
- Receptors, NK Cell Lectin-Like
- Signal Transduction/immunology
- Syk Kinase
- Tyrosine/metabolism
- src-Family Kinases/antagonists & inhibitors
- src-Family Kinases/physiology
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Affiliation(s)
- Llewellyn H Mason
- Laboratory of Experimental Immunology, National Cancer Institute, Center for Cancer Research, Frederick, MD 21702, USA
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33
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Maier JA, Brugel TA, Sabat M, Golebiowski A, Laufersweiler MJ, VanRens JC, Hopkins CR, De B, Hsieh LC, Brown KK, Easwaran V, Janusz MJ. Development of N-4,6-pyrimidine-N-alkyl-N'-phenyl ureas as orally active inhibitors of lymphocyte specific tyrosine kinase. Bioorg Med Chem Lett 2006; 16:3646-50. [PMID: 16682201 DOI: 10.1016/j.bmcl.2006.04.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 04/21/2006] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
A new class of lymphocyte specific tyrosine kinase (lck) inhibitors based on an N-4,6-pyrimidine-N-alkyl-N'-phenyl urea scaffold is described. Many of these compounds showed low-nanomolar inhibition of lck kinase activity as well as IL-2 synthesis from Jurkat cells. One of these analogs, 7i, was shown to be orally efficacious by in vivo testing in a rat adjuvant-induced arthritis study.
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Affiliation(s)
- Jennifer A Maier
- Procter & Gamble Pharmaceuticals, Health Care Research Center, 8700 Mason-Montgomery Rd. Mason, OH 45040, USA
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34
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Chan WE, Chen SSL. Downregulation of human immunodeficiency virus type 1 Gag expression by a gp41 cytoplasmic domain fusion protein. Virology 2006; 348:418-29. [PMID: 16472834 DOI: 10.1016/j.virol.2006.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 10/21/2005] [Accepted: 01/06/2006] [Indexed: 11/17/2022]
Abstract
The cytoplasmic domain of human immunodeficiency virus type 1 (HIV-1) envelope (Env) transmembrane protein gp41 interacts with the viral matrix MA protein, which facilitates incorporation of the trimeric Env complex into the virus. It is thus feasible to design an anti-HIV strategy targeting this interaction. We herein describe that Gag expression can be downregulated by a cytoplasmic domain fusion protein of the Env transmembrane protein, beta-galactosidase (beta-gal)/706-856, which contains the cytoplasmic tail of gp41 fused at the C terminus of Escherichia coli beta-gal. This mediator depleted intracellular Gag molecules in a dose-dependent manner. Sucrose gradient ultracentrifugation and confocal microscopy revealed that Gag and beta-gal/706-856 had stable interactions and formed aggregated complexes in perinuclear, intracellular sites. Pulse-chase and cycloheximide chase analyses demonstrated that this mediator enhanced unmyristylated Gag degradation. The results demonstrate a novel mode of HIV-1 Gag downregulation by directing Gag to an intracellular site via the interaction of Gag with a gp41 cytoplasmic domain fusion protein.
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Affiliation(s)
- Woan-Eng Chan
- Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China
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35
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Dowden J, Ward SG. Inhibitors of p56lck: assessing their potential as tools for manipulating T-lymphocyte activation. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.11.2.295] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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36
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Abstract
In the central nervous system (CNS), Src and other Src family kinases are widely expressed and are abundant in neurons. Src has been implicated in proliferation and differentiation during the development of the CNS. But Src is highly expressed in fully differentiated neurons in the developed CNS, implying additional functions of this kinase. Over the past decade, a large body of evidence has accumulated showing that a main function of Src is to upregulate the activity of N-methyl-D-aspartate (NMDA) receptors and other ion channels. NMDA receptors (NMDARs) are a principal subtype of glutamate receptors, which mediate fast excitatory transmission at most central synapses. In this review, we focus on Src as a regulator of NMDARs and on the role of Src in NMDAR-dependent synaptic plasticity. We also describe recent studies that give insights into the regulation of Src itself at glutamatergic synapses. By upregulating the function of NMDARs, Src gates the production of NMDAR-dependent synaptic potentiation and plasticity. Thus, Src may be critical for processes underlying physiological plasticity, including learning and memory, and pathological plasticity, such as pain and epilepsy.
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Affiliation(s)
- Lorraine V Kalia
- Programme in Brain and Behaviour, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada M5G 1X8
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37
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Abstract
Src family kinases are prototypical modular signaling proteins. Their conserved domain organization includes a myristoylated N-terminal segment followed by SH3, SH2, and tyrosine kinase domains, and a short C-terminal tail. Structural dissection of Src kinases has elucidated the canonical mechanisms of phosphotyrosine recognition by the SH2 domain and proline-motif recognition by the SH3 domain. Crystallographic analysis of nearly intact Src kinases in the autoinhibited state has shown that these protein interaction motifs turn inward and lock the kinase in an inactive conformation via intramolecular interactions. The autoinhibited Src kinase structures reveal a mode of domain assembly used by other tyrosine kinases outside the Src family, including Abl and likely Tec family kinases. Furthermore, they illustrate the underlying regulatory principles that have proven to be general among diverse modular signaling proteins. Although there is considerable structural information available for the autoinhibited conformation of Src kinases, how they may assemble into active signaling complexes with substrates and regulators remains largely unexplored.
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Affiliation(s)
- Titus J Boggon
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Dana-Farber Cancer Institute, 44 Binney St., Boston, MA 02115, USA
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38
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Bosselut R. CD4/CD8-lineage differentiation in the thymus: from nuclear effectors to membrane signals. Nat Rev Immunol 2004; 4:529-40. [PMID: 15229472 DOI: 10.1038/nri1392] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Rémy Bosselut
- Laboratory of Immune Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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39
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Singer A, Bosselut R. CD4/CD8 coreceptors in thymocyte development, selection, and lineage commitment: analysis of the CD4/CD8 lineage decision. Adv Immunol 2004; 83:91-131. [PMID: 15135629 DOI: 10.1016/s0065-2776(04)83003-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Alfred Singer
- Experimental Immunology Branch, National Cancer Institute, Bethesda, Maryland 20892, USA
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40
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Kim PW, Sun ZYJ, Blacklow SC, Wagner G, Eck MJ. A Zinc Clasp Structure Tethers Lck to T Cell Coreceptors CD4 and CD8. Science 2003; 301:1725-8. [PMID: 14500983 DOI: 10.1126/science.1085643] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The T cell coreceptors CD4 and CD8 both associate via their cytoplasmic tails with the N-terminus of the Src-family tyrosine kinase Lck. These interactions require zinc and are critical for T cell development and activation. We examined the folding and solution structures of ternary CD4-Lck-Zn2+ and CD8alpha-Lck-Zn2+ complexes. The coreceptor tails and the Lck N-terminus are unstructured in isolation but assemble in the presence of zinc to form compactly folded heterodimeric domains. The cofolded complexes have similar "zinc clasp" cores that are augmented by distinct structural elements. A dileucine motif required for clathrin-mediated endocytosis of CD4 is masked by Lck.
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Affiliation(s)
- Peter W Kim
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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41
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Denning TL, Qi H, König R, Scott KG, Naganuma M, Ernst PB. CD4+ Th cells resembling regulatory T cells that inhibit chronic colitis differentiate in the absence of interactions between CD4 and class II MHC. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:2279-86. [PMID: 12928372 DOI: 10.4049/jimmunol.171.5.2279] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Regulatory CD4+ Th cells can prevent many autoimmune diseases; however, the factors selecting for these cells remain poorly defined. In transgenic mice with a mutation in the CD4 binding region on class II MHC, the disruption of CD4-class II interactions selected for CD4+ Th cells that expressed surface markers and cytokines associated with regulatory Th cells. Th cells from these mice were enriched for CD45RB(low) as well as CD25+, while they expressed high levels of the transcription factor associated with regulatory T cells, Foxp3, and cytokines, including IL-4, IL-10, and IFN-gamma mRNA and protein. These regulatory Th cells inhibited the function of APCs via IL-10 production, and adoptive transfer of these cells prevented weight loss and inflammation in a model of colitis. CD4+ regulatory Th cells emerged only when interactions between CD4 and class II MHC were deficient on cells of nonhemopoietic origin. These data support a novel model controlling the differentiation of regulatory Th cells and suggest that interactions between CD4 and class II MHC may a useful target for re-educating T cells as a treatment for inflammatory diseases.
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Affiliation(s)
- Timothy L Denning
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
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42
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Jordan S, Rodgers W. T cell glycolipid-enriched membrane domains are constitutively assembled as membrane patches that translocate to immune synapses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:78-87. [PMID: 12816985 DOI: 10.4049/jimmunol.171.1.78] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In T cells, glycolipid-enriched membrane (GEM) domains, or lipid rafts, are assembled into immune synapses in response to Ag presentation. However, the properties of T cell GEM domains in the absence of stimulatory signals, such as their size and distribution in the plasma membrane, are less clear. To address this question, we used confocal microscopy to measure GEM domains in unstimulated T cells expressing a GEM-targeted green fluorescent protein molecule. Our experiments showed that the GEM domains were assembled into membrane patches that were micrometers in size, as evidenced by a specific enrichment of GEM-associated molecules and resistance of the patches to extraction by Triton X-100. However, treatment of cells with latrunculin B disrupted the patching of the GEM domains and their resistance to Triton X-100. Similarly, the patches were coenriched with F-actin, and actin occurred in the detergent-resistant GEM fraction of T cells. Live-cell imaging showed that the patches were mobile and underwent translocation in the plasma membrane to immune synapses in stimulated T cells. Targeting of GEM domains to immune synapses was found to be actin-dependent, and required phosphatidylinositol 3-kinase activity and myosin motor proteins. We conclude from our results that T cell GEM domains are constitutively assembled by the actin cytoskeleton into micrometer-sized membrane patches, and that GEM domains and the GEM-enriched patches can function as a vehicle for targeting molecules to immune synapses.
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Affiliation(s)
- Stephen Jordan
- Molecular Immunogenetics Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
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43
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Ike H, Kosugi A, Kato A, Iino R, Hirano H, Fujiwara T, Ritchie K, Kusumi A. Mechanism of Lck recruitment to the T-cell receptor cluster as studied by single-molecule-fluorescence video imaging. Chemphyschem 2003; 4:620-6. [PMID: 12836486 DOI: 10.1002/cphc.200300670] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hiroshi Ike
- Kusumi Membrane Organizer Project, Exploratory Research for Advancement of Technology Organization (ERATO), JST, Nagoya, 460-0012, Japan
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44
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Abstract
Adhesive interactions play important roles in coordinating T-cell migration and activation, specifically in the formation of the immunological synapse (IS), a specialized cell-cell junction. Recent demonstrations show several molecules implicated in T-cell signaling, including Vav, ADAP, and Rap-1, have major roles in integrin regulation and place adhesion molecules at center stage in addressing the question: what are the signals involved in the formation of the IS and full T-cell activation? This review focuses on the role of integrins as an essential system for both physical adhesion and signaling in T-cell activation. The role of integrins appears to be quite distinct from classical costimulation and has been largely overlooked due to the ubiquitous use of serum in lymphocyte functional assays. Each major signal transduction pathway has branches leading to the nucleus and others that feed back on cytoskeletal and membrane regulation at the IS.
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Affiliation(s)
- Tasha N Sims
- Molecular Pathogenesis Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
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45
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Abstract
The novel protein kinase C (PKC) isoform, PKC theta, is selectively expressed in T lymphocytes and is a sine qua non for T cell antigen receptor (TCR)-triggered activation of mature T cells. Productive engagement of T cells by antigen-presenting cells (APCs) results in recruitment of PKC theta to the T cell-APC contact area--the immunological synapse--where it interacts with several signaling molecules to induce activation signals essential for productive T cell activation and IL-2 production. The transcription factors NF-kappa B and AP-1 are the primary physiological targets of PKC theta, and efficient activation of these transcription factors by PKC theta requires integration of TCR and CD28 costimulatory signals. PKC theta cooperates with the protein Ser/Thr phosphatase, calcineurin, in transducing signals leading to activation of JNK, NFAT, and the IL-2 gene. PKC theta also promotes T cell cycle progression and regulates programmed T cell death. The exact mode of regulation and immediate downstream substrates of PKC theta are still largely unknown. Identification of these molecules and determination of their mode of operation with respect to the function of PKC theta will provide essential information on the mechanism of T cell activation. The selective expression of PKC theta in T cells and its essential role in mature T cell activation establish it as an attractive drug target for immunosuppression in transplantation and autoimmune diseases.
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Affiliation(s)
- Noah Isakov
- Department of Microbiology and Immunology, Faculty of Health Sciences, and the Cancer Research Center, Ben Gurion University of the Negev, Beer Sheva 84105, Israel.
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46
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Tang Q, Subudhi SK, Henriksen KJ, Long CG, Vives F, Bluestone JA. The Src family kinase Fyn mediates signals induced by TCR antagonists. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:4480-7. [PMID: 11970992 DOI: 10.4049/jimmunol.168.9.4480] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
FcR nonbinding anti-CD3 epsilon mAbs elicit partial TCR signaling that leads to T cell unresponsiveness and tolerance in vivo. In this study, the membrane-proximal events that promote T cell inactivation by FcR nonbinding anti-CD3 mAbs were examined. In the context of FcR nonbinding anti-CD3, TCR complexes did not aggregate and failed to translocate into glycolipid-enriched membrane microdomains. Furthermore, FcR nonbinding anti-CD3 mAbs induced tyrosine phosphorylation of the Fyn substrate Cbl, but not the ZAP-70 substrate linker for activation of T cells. Overexpression of Fyn, but not Lck, restored the mitogenicity of FcR nonbinding anti-CD3 in primary T cells. Taken together, these results suggest that Fyn mediates the partial signaling induced by TCR antagonists.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- CD3 Complex/immunology
- CD3 Complex/metabolism
- Cells, Cultured
- Lymphocyte Activation
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/physiology
- Membrane Microdomains/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Models, Immunological
- Phosphorylation
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-cbl
- Proto-Oncogene Proteins c-fyn
- Receptor-CD3 Complex, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/antagonists & inhibitors
- Signal Transduction
- T-Lymphocytes/enzymology
- T-Lymphocytes/immunology
- Transduction, Genetic
- Ubiquitin-Protein Ligases
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Affiliation(s)
- Qizhi Tang
- The Diabetes Center, University of California, San Francisco, CA 94143, USA
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47
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Quiñones-Kochs MI, Buonocore L, Rose JK. Role of N-linked glycans in a human immunodeficiency virus envelope glycoprotein: effects on protein function and the neutralizing antibody response. J Virol 2002; 76:4199-211. [PMID: 11932385 PMCID: PMC155056 DOI: 10.1128/jvi.76.9.4199-4211.2002] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope (Env) glycoprotein of human immunodeficiency virus (HIV) contains 24 N-glycosylation sites covering much of the protein surface. It has been proposed that one role of these carbohydrates is to form a shield that protects the virus from immune recognition. Strong evidence for such a role for glycosylation has been reported for simian immunodeficiency virus (SIV) mutants lacking glycans in the V1 region of Env (J. N. Reitter, R. E. Means, and R. C. Desrosiers, Nat. Med. 4:679-684, 1998). Here we used recombinant vesicular stomatitis viruses (VSVs) expressing HIV Env glycosylation mutants to determine if removal of carbohydrates in the V1 and V2 domains affected protein function and the generation of neutralizing antibodies in mice. Mutations that eliminated one to six of the sites for N-linked glycosylation in the V1 and V2 loops were introduced into a gene encoding the HIV type 1 primary isolate 89.6 envelope glycoprotein with its cytoplasmic domain replaced by that of the VSV G glycoprotein. The membrane fusion activities of the mutant proteins were studied in a syncytium induction assay. The transport and processing of the mutant proteins were studied with recombinant VSVs expressing mutant Env G proteins. We found that HIV Env V1 and V2 glycosylation mutants were no better than wild-type envelope at inducing antibodies neutralizing wild-type Env, although an Env mutant lacking glycans appeared somewhat more sensitive to neutralization by antibodies raised to mutant or wild-type Env. These results indicate significant differences between SIV and HIV with regard to the roles of glycans in the V1 and V2 domains.
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Affiliation(s)
- Miriam I Quiñones-Kochs
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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48
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Dustin ML, Bromley SK, Davis MM, Zhu C. Identification of self through two-dimensional chemistry and synapses. Annu Rev Cell Dev Biol 2002; 17:133-57. [PMID: 11687486 DOI: 10.1146/annurev.cellbio.17.1.133] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells in the immune and nervous systems communicate through informational synapses. The two-dimensional chemistry underlying the process of synapse formation is beginning to be explored using fluorescence imaging and mechanical techniques. Early analysis of two-dimensional kinetic rates (k(on) and k(off)) and equilibrium constants (K(d)) provides a number of biological insights. First, there are two regimes for adhesion-one disordered with slow k(on) and the other self-ordered with 10(4)-fold faster k(on). Despite huge variation in two-dimensional k(on), the two-dimensional k(off) is like k(off) in solution, and two-dimensional k(off) is more closely related to intrinsic properties of the interaction than the two-dimensional k(on). Thus difference in k(off) can be used to set signaling thresholds. Early signaling complexes are compartmentalized to generate synergistic signaling domains. Immune antigen receptor components have a role in neural synapse editing. This suggests significant parallels in informational synapse formation based on common two-dimensional chemistry and signaling strategies.
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Affiliation(s)
- M L Dustin
- Skirball Institute of Molecular Medicine, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA.
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49
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Loomis JS, Bowzard JB, Courtney RJ, Wills JW. Intracellular trafficking of the UL11 tegument protein of herpes simplex virus type 1. J Virol 2001; 75:12209-19. [PMID: 11711612 PMCID: PMC116118 DOI: 10.1128/jvi.75.24.12209-12219.2001] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Growing evidence indicates that herpes simplex virus type 1 (HSV-1) acquires its final envelope in the trans-Golgi network (TGN). During the envelopment process, the viral nucleocapsid as well as the envelope and tegument proteins must arrive at this site in order to be incorporated into assembling virions. To gain a better understanding of how these proteins associate with cellular membranes and target to the correct compartment, we have been studying the intracellular trafficking properties of the small tegument protein encoded by the U(L)11 gene of HSV-1. This 96-amino-acid, myristylated protein accumulates on the cytoplasmic face of internal membranes, where it is thought to play a role in nucleocapsid envelopment and egress. When expressed in the absence of other HSV-1 proteins, the UL11 protein localizes to the Golgi apparatus, and previous deletion analyses have revealed that the membrane-trafficking information is contained within the first 49 amino acids. The goal of this study was to map the functional domains required for proper Golgi membrane localization. In addition to N-terminal myristylation, which allows for weak membrane binding, UL11 appears to be palmitylated on one or more of three consecutive N-terminal cysteines. Using membrane-pelleting experiments and confocal microscopy, we show that palmitylation of UL11 is required for both Golgi targeting specificity and strong membrane binding. Furthermore, we found that a conserved acidic cluster within the first half of UL11 is required for the recycling of this tegument protein from the plasma membrane to the Golgi apparatus. Taken together, our results demonstrate that UL11 has highly dynamic membrane-trafficking properties, which suggests that it may play multiple roles on the plasma membrane as well as on the nuclear and TGN membranes.
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Affiliation(s)
- J S Loomis
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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50
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Wang Q, Malherbe L, Zhang D, Zingler K, Glaichenhaus N, Killeen N. CD4 promotes breadth in the TCR repertoire. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:4311-20. [PMID: 11591754 DOI: 10.4049/jimmunol.167.8.4311] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A diverse population of MHC class II-restricted CD4 lineage T cells develops in mice that lack expression of the CD4 molecule. In this study, we show that the TCR repertoire selected in the absence of CD4 is distinct, but still overlapping in its properties with that selected in the presence of CD4. Immunization of mice lacking CD4 caused the clonal expansion of T cells that showed less breadth in the range of Ag-binding properties exhibited by their TCRs. Specifically, the CD4-deficient Ag-specific TCR repertoire was depleted of TCRs that demonstrated low-affinity binding to their ligands. The data thus suggest a key role for CD4 in broadening the TCR repertoire by potentiating productive TCR signaling and clonal expansion in response to the engagement of low-affinity antigenic ligands.
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Affiliation(s)
- Q Wang
- Department of Microbiology and Immunology, University of California, San Francisco, CA 94143, USA
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