1
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Stinchcombe JC, Asano Y, Kaufman CJG, Böhlig K, Peddie CJ, Collinson LM, Nadler A, Griffiths GM. Ectocytosis renders T cell receptor signaling self-limiting at the immune synapse. Science 2023; 380:818-823. [PMID: 37228189 DOI: 10.1126/science.abp8933] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/28/2023] [Indexed: 05/27/2023]
Abstract
Cytotoxic T lymphocytes (CTLs) kill virus-infected and cancer cells through T cell receptor (TCR) recognition. How CTLs terminate signaling and disengage to allow serial killing has remained a mystery. TCR activation triggers membrane specialization within the immune synapse, including the production of diacylglycerol (DAG), a lipid that can induce negative membrane curvature. We found that activated TCRs were shed into DAG-enriched ectosomes at the immune synapse rather than internalized through endocytosis, suggesting that DAG may contribute to the outward budding required for ectocytosis. Budding ectosomes were endocytosed directly by target cells, thereby terminating TCR signaling and simultaneously disengaging the CTL from the target cell to allow serial killing. Thus, ectocytosis renders TCR signaling self-limiting.
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Affiliation(s)
- Jane C Stinchcombe
- Cambridge Institute for Medical Research, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Yukako Asano
- Cambridge Institute for Medical Research, Keith Peters Building, Cambridge CB2 0XY, UK
| | | | - Kristin Böhlig
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | | | | | - André Nadler
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, Keith Peters Building, Cambridge CB2 0XY, UK
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2
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Teppert K, Wang X, Anders K, Evaristo C, Lock D, Künkele A. Joining Forces for Cancer Treatment: From "TCR versus CAR" to "TCR and CAR". Int J Mol Sci 2022; 23:ijms232314563. [PMID: 36498890 PMCID: PMC9739809 DOI: 10.3390/ijms232314563] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/14/2022] [Accepted: 11/19/2022] [Indexed: 11/24/2022] Open
Abstract
T cell-based immunotherapy has demonstrated great therapeutic potential in recent decades, on the one hand, by using tumor-infiltrating lymphocytes (TILs) and, on the other hand, by engineering T cells to obtain anti-tumor specificities through the introduction of either engineered T cell receptors (TCRs) or chimeric antigen receptors (CARs). Given the distinct design of both receptors and the type of antigen that is encountered, the requirements for proper antigen engagement and downstream signal transduction by TCRs and CARs differ. Synapse formation and signal transduction of CAR T cells, despite further refinement of CAR T cell designs, still do not fully recapitulate that of TCR T cells and might limit CAR T cell persistence and functionality. Thus, deep knowledge about the molecular differences in CAR and TCR T cell signaling would greatly advance the further optimization of CAR designs and elucidate under which circumstances a combination of both receptors would improve the functionality of T cells for cancer treatment. Herein, we provide a comprehensive review about similarities and differences by directly comparing the architecture, synapse formation and signaling of TCRs and CARs, highlighting the knowns and unknowns. In the second part of the review, we discuss the current status of combining CAR and TCR technologies, encouraging a change in perspective from "TCR versus CAR" to "TCR and CAR".
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Affiliation(s)
- Karin Teppert
- Miltenyi Biotec B.V. & Co. KG, 51429 Bergisch Gladbach, Germany
| | - Xueting Wang
- Miltenyi Biotec B.V. & Co. KG, 51429 Bergisch Gladbach, Germany
| | - Kathleen Anders
- German Cancer Consortium (DKTK), 10117 Berlin, Germany
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - César Evaristo
- Miltenyi Biotec B.V. & Co. KG, 51429 Bergisch Gladbach, Germany
| | - Dominik Lock
- Miltenyi Biotec B.V. & Co. KG, 51429 Bergisch Gladbach, Germany
| | - Annette Künkele
- German Cancer Consortium (DKTK), 10117 Berlin, Germany
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- Department of Pediatric Oncology and Hematology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 13353 Berlin, Germany
- Correspondence:
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3
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Wang H, Song X, Shen L, Wang X, Xu C. Exploiting T cell signaling to optimize engineered T cell therapies. Trends Cancer 2021; 8:123-134. [PMID: 34810156 DOI: 10.1016/j.trecan.2021.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/19/2021] [Accepted: 10/28/2021] [Indexed: 11/15/2022]
Abstract
Engineered T cell therapies, mainly chimeric antigen receptor (CAR)-T and T cell receptor (TCR)-T, have become the new frontier of cancer treatment. CAR-T and TCR-T therapies differ in many aspects, including cell persistence and toxicity, leading to different therapeutic outcomes. Both TCR and CAR recognize antigens and trigger T cell mediated antitumor response, but they have distinct molecular structures and signaling properties. TCR represents one of the most complex receptors, while CAR is a single-chain chimera integrating modules from multiple immune receptors. Understanding the mechanisms underlying the strengths and limitations of both systems can pave the way for the development of next-generation T cell therapy. This review synthesizes recent findings on TCR and CAR signaling and highlights the potential strategies of T cell engineering by signaling refinement.
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Affiliation(s)
- Haopeng Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Shanghai Clinical Research and Trial Center, Shanghai, China.
| | - Xianming Song
- Department of Hematology, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | | | | | - Chenqi Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China; School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, Zhejiang, China.
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4
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Evnouchidou I, Caillens V, Koumantou D, Saveanu L. The role of endocytic trafficking in antigen T Cell Receptor activation. Biomed J 2021; 45:310-320. [PMID: 34592497 PMCID: PMC9250096 DOI: 10.1016/j.bj.2021.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 12/14/2022] Open
Abstract
Antigen T cell receptors (TCR) recognize antigenic peptides displayed by the major histocompatibility complex (pMHC) and play a critical role in T cell activation. The levels of TCR complexes at the cell surface, where signaling is initiated, depend on the balance between TCR synthesis, recycling and degradation. Cell surface TCR interaction with pMHC leads to receptor clustering and formation of a tight T cell-APC contact, the immune synapse, from which the activated TCR is internalized. While TCR internalization from the immune synapse has been initially considered to arrest TCR signaling, recent evidence support the hypothesis that the internalized receptor continues to signal from specialized endosomes. Here, we review the molecular mechanisms of TCR endocytosis and recycling, both in steady state and after T cell activation. We then discuss the experimental evidence in favor of endosomal TCR signaling and its possible consequences on T cell activation.
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Affiliation(s)
- Irini Evnouchidou
- Université de Paris, Centre de Recherche sur L'inflammation, INSERM U1149, CNRS ERL8252, Paris, France; Inovarion, Paris, France.
| | - Vivien Caillens
- Université de Paris, Centre de Recherche sur L'inflammation, INSERM U1149, CNRS ERL8252, Paris, France; Inovarion, Paris, France
| | - Despoina Koumantou
- Université de Paris, Centre de Recherche sur L'inflammation, INSERM U1149, CNRS ERL8252, Paris, France; Inovarion, Paris, France
| | - Loredana Saveanu
- Université de Paris, Centre de Recherche sur L'inflammation, INSERM U1149, CNRS ERL8252, Paris, France; Inovarion, Paris, France.
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5
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Onnis A, Baldari CT. Orchestration of Immunological Synapse Assembly by Vesicular Trafficking. Front Cell Dev Biol 2019; 7:110. [PMID: 31334230 PMCID: PMC6616304 DOI: 10.3389/fcell.2019.00110] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/03/2019] [Indexed: 12/15/2022] Open
Abstract
Ligation of the T-cell antigen receptor (TCR) by cognate peptide bound to the Major Histocompatibility Complex on the surface of an antigen-presenting cell (APC) leads to the spatial reorganization of the TCR and accessory receptors to form a specialized area of intimate contact between T cell and APC, known as the immunological synapse (IS), where signals are deciphered, coordinated, and integrated to promote T cell activation. With the discovery that an endosomal TCR pool contributes to IS assembly and function by undergoing polarized recycling to the IS, recent years have witnessed a shift from a plasma membrane-centric view of the IS to the vesicular trafficking events that occur at this location following the TCR-dependent translocation of the centrosome toward the synaptic membrane. Here we will summarize our current understanding of the trafficking pathways that are responsible for the steady delivery of endosomal TCRs, kinases, and adapters to the IS to sustain signaling, as well as of the endocytic pathways responsible for signal termination. We will also discuss recent evidence highlighting a role for endosomes in sustaining TCR signaling after its internalization at the IS and identifying the IS as a site of formation and release of extracellular vesicles that allow for transcellular communication with the APC.
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Affiliation(s)
- Anna Onnis
- Department of Life Sciences, University of Siena, Siena, Italy
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6
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Abstract
T cell receptors (TCRs) are protein complexes formed by six different polypeptides. In most T cells, TCRs are composed of αβ subunits displaying immunoglobulin-like variable domains that recognize peptide antigens associated with major histocompatibility complex molecules expressed on the surface of antigen-presenting cells. TCRαβ subunits are associated with the CD3 complex formed by the γ, δ, ε, and ζ subunits, which are invariable and ensure signal transduction. Here, we review how the expression and function of TCR complexes are orchestrated by several fine-tuned cellular processes that encompass (a) synthesis of the subunits and their correct assembly and expression at the plasma membrane as a single functional complex, (b) TCR membrane localization and dynamics at the plasma membrane and in endosomal compartments, (c) TCR signal transduction leading to T cell activation, and (d) TCR degradation. These processes balance each other to ensure efficient T cell responses to a variety of antigenic stimuli while preventing autoimmunity.
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Affiliation(s)
- Andrés Alcover
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
| | - Balbino Alarcón
- Severo Ochoa Center for Molecular Biology, CSIC-UAM, Madrid 28049, Spain;
| | - Vincenzo Di Bartolo
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
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7
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Zimmermann K, Eells R, Heinrich F, Rintoul S, Josey B, Shekhar P, Lösche M, Stern LJ. The cytosolic domain of T-cell receptor ζ associates with membranes in a dynamic equilibrium and deeply penetrates the bilayer. J Biol Chem 2017; 292:17746-17759. [PMID: 28893902 PMCID: PMC5663876 DOI: 10.1074/jbc.m117.794370] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/21/2017] [Indexed: 11/06/2022] Open
Abstract
Interactions between lipid bilayers and the membrane-proximal regions of membrane-associated proteins play important roles in regulating membrane protein structure and function. The T-cell antigen receptor is an assembly of eight single-pass membrane-spanning subunits on the surface of T lymphocytes that initiates cytosolic signaling cascades upon binding antigens presented by MHC-family proteins on antigen-presenting cells. Its ζ-subunit contains multiple cytosolic immunoreceptor tyrosine-based activation motifs involved in signal transduction, and this subunit by itself is sufficient to couple extracellular stimuli to intracellular signaling events. Interactions of the cytosolic domain of ζ (ζcyt) with acidic lipids have been implicated in the initiation and regulation of transmembrane signaling. ζcyt is unstructured in solution. Interaction with acidic phospholipids induces structure, but its disposition when bound to lipid bilayers is controversial. Here, using surface plasmon resonance and neutron reflection, we characterized the interaction of ζcyt with planar lipid bilayers containing mixtures of acidic and neutral lipids. We observed two binding modes of ζcyt to the bilayers in dynamic equilibrium: one in which ζcyt is peripherally associated with lipid headgroups and one in which it penetrates deeply into the bilayer. Such an equilibrium between the peripherally bound and embedded forms of ζcyt apparently controls accessibility of the immunoreceptor tyrosine-based activation signal transduction pathway. Our results reconcile conflicting findings of the ζ structure reported in previous studies and provide a framework for understanding how lipid interactions regulate motifs to tyrosine kinases and may regulate the T-cell antigen receptor biological activities for this cell-surface receptor system.
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Affiliation(s)
| | | | - Frank Heinrich
- the Departments of Physics and
- the National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, Maryland 20899
| | | | | | | | - Mathias Lösche
- the Departments of Physics and
- the National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, Maryland 20899
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, and
| | - Lawrence J Stern
- From the Departments of Pathology and
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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8
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Hsu H, Baldwin CL, Telfer JC. The Endocytosis and Signaling of the γδ T Cell Coreceptor WC1 Are Regulated by a Dileucine Motif. THE JOURNAL OF IMMUNOLOGY 2015; 194:2399-406. [DOI: 10.4049/jimmunol.1402020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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9
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Fernández-Arenas E, Calleja E, Martínez-Martín N, Gharbi SI, Navajas R, García-Medel N, Penela P, Alcamí A, Mayor F, Albar JP, Alarcón B. β-Arrestin-1 mediates the TCR-triggered re-routing of distal receptors to the immunological synapse by a PKC-mediated mechanism. EMBO J 2014; 33:559-77. [PMID: 24502978 DOI: 10.1002/embj.201386022] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
T-cell receptors (TCR) recognize their antigen ligand at the interface between T cells and antigen-presenting cells, known as the immunological synapse (IS). The IS provides a means of sustaining the TCR signal which requires the continual supply of new TCRs. These are endocytosed and redirected from distal membrane locations to the IS. In our search for novel cytoplasmic effectors, we have identified β-arrestin-1 as a ligand of non-phosphorylated resting TCRs. Using dominant-negative and knockdown approaches we demonstrate that β-arrestin-1 is required for the internalization and downregulation of non-engaged bystander TCRs. Furthermore, TCR triggering provokes the β-arrestin-1-mediated downregulation of the G-protein coupled chemokine receptor CXCR4, but not of other control receptors. We demonstrate that β-arrestin-1 recruitment to the TCR, and bystander TCR and CXCR4 downregulation, are mechanistically mediated by the TCR-triggered PKC-mediated phosphorylation of β-arrestin-1 at Ser163. This mechanism allows the first triggered TCRs to deliver a stop migration signal, and to promote the internalization of distal TCRs and CXCR4 and their translocation to the IS. This receptor crosstalk mechanism is critical to sustain the TCR signal.
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Affiliation(s)
- Elena Fernández-Arenas
- Centro de Biología Molecular "Severo Ochoa", Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Madrid, Spain
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10
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Bettini ML, Bettini M, Vignali DAA. T-cell receptor retrogenic mice: a rapid, flexible alternative to T-cell receptor transgenic mice. Immunology 2012; 136:265-72. [PMID: 22348644 DOI: 10.1111/j.1365-2567.2012.03574.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The T-cell receptor (TCR) is unique in its complexity. It determines not only positive (life) and negative (death) selection in the thymus, but also mediates proliferation, anergy, differentiation, cytotoxicity and cytokine production in the periphery. Through its association with six CD3 signalling chains (εγ, δε and ζζ), the TCR is capable of recognizing an extensive variety of antigenic peptides, from both pathogens and self-antigens, and translating these interactions into multiple signalling pathways that mediate diverse T-cell developmental and functional responses. The analysis of TCR biology has been revolutionized by the development of TCR transgenic mice, which express a single clonotypic T-cell population, with diverse specificities and genetic backgrounds. However, they are time consuming to generate and characterize, limiting the analysis of large numbers of TCR over a short period of time in multiple genetic backgrounds. The recent development of TCR retrogenic technology resolves these limitations and could in time have a similarly important impact on our understanding of T-cell development and function. In this review, we will discuss the advantages and limitations of retrogenic technology compared with the generation and use of TCR transgenic mice for studying all aspects of T-cell biology.
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Affiliation(s)
- Matthew L Bettini
- Department of Immunology, St Jude Children's Research Hospital, Memphis, TN 38105, USA
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11
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Tonic ubiquitylation controls T-cell receptor:CD3 complex expression during T-cell development. EMBO J 2010; 29:1285-98. [PMID: 20150895 DOI: 10.1038/emboj.2010.10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 01/15/2010] [Indexed: 01/06/2023] Open
Abstract
Expression of the T-cell receptor (TCR):CD3 complex is tightly regulated during T-cell development. The mechanism and physiological role of this regulation are unclear. Here, we show that the TCR:CD3 complex is constitutively ubiquitylated in immature double positive (DP) thymocytes, but not mature single positive (SP) thymocytes or splenic T cells. This steady state, tonic CD3 monoubiquitylation is mediated by the CD3varepsilon proline-rich sequence, Lck, c-Cbl, and SLAP, which collectively trigger the dynamin-dependent downmodulation, lysosomal sequestration and degradation of surface TCR:CD3 complexes. Blocking this tonic ubiquitylation by mutating all the lysines in the CD3 cytoplasmic tails significantly upregulates TCR levels on DP thymocytes. Mimicking monoubiquitylation by expression of a CD3zeta-monoubiquitin (monoUb) fusion molecule significantly reduces TCR levels on immature thymocytes. Moreover, modulating CD3 ubiquitylation alters immunological synapse (IS) formation and Erk phosphorylation, thereby shifting the signalling threshold for positive and negative selection, and regulatory T-cell development. Thus, tonic TCR:CD3 ubiquitylation results in precise regulation of TCR expression on immature T cells, which is required to maintain the fidelity of T-cell development.
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12
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Hunter MG, McLemore M, Link DC, Loveland M, Copelan A, Avalos BR. Divergent pathways in COS-7 cells mediate defective internalization and intracellular routing of truncated G-CSFR forms in SCN/AML. PLoS One 2008; 3:e2452. [PMID: 18560579 PMCID: PMC2409964 DOI: 10.1371/journal.pone.0002452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 05/13/2008] [Indexed: 11/18/2022] Open
Abstract
Background Expression of truncated G-CSFR forms in patients with SCN/AML induces hyperproliferation and prolonged cell survival. Previously, we showed that ligand internalization is delayed and degradation of truncated G-CSFR forms is defective in patients with SCN/AML. Methodology/Principal Findings In this study, we investigated the potential roles of dileucine and tyrosine-based motifs within the cytoplasmic domain of the G-CSFR in modulating ligand/receptor internalization. Using standard binding assays with radiolabeled ligand and COS-7 cells, substitutions in the dileucine motif or deletion of tyrosine residues in the G-CSFR did not alter internalization. Attachment of the transferrin receptor YTRF internalization motif to a truncated G-CSFR form from a patient with SCN/AML corrected defective internalization, but not receptor degradation suggesting that receptor internalization and degradation occur independently via distinct domains and/or processes. Conclusions Our data suggest that distinct domains within the G-CSFR mediate separate processes for receptor internalization and degradation. Our findings using standard binding assays differ from recently published data utilizing flow cytometry.
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Affiliation(s)
- Melissa G. Hunter
- Pulmonary, Allergy, Critical Care and Sleep Medicine, The Ohio State University, Columbus, Ohio, United States of America
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Morgan McLemore
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Daniel C. Link
- Division of Bone Marrow Transplantation and Stem Cell Biology, Washington University, St. Louis, Missouri, United States of America
| | - Megan Loveland
- Division of Hematology/Oncology, The Ohio State University, Columbus, Ohio, United States of America
| | - Alexander Copelan
- Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Belinda R. Avalos
- Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, United States of America
- Division of Hematology/Oncology, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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13
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Meraner P, Horejsí V, Wolpl A, Fischer GF, Stingl G, Maurer D. Dendritic Cells Sensitize TCRs through Self-MHC-Mediated Src Family Kinase Activation. THE JOURNAL OF IMMUNOLOGY 2007; 178:2262-71. [PMID: 17277131 DOI: 10.4049/jimmunol.178.4.2262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is unclear whether peptide-MHC class II (pMHC) complexes on distinct types of APCs differ in their capacity to trigger TCRs. In this study, we show that individual cognate pMHC complexes displayed by dendritic cells (DCs), as compared with nonprofessional APCs, are far better in productively triggering Ag-specific TCRs independently of conventional costimulation. As we further show, this is accomplished by the unique ability of DCs to robustly activate the Src family kinases (SFKs) Lck and Fyn in T cells even in the absence of cognate peptide. Instead, this form of SFK activation depends on interactions of DC-displayed MHC with TCRs of appropriate restriction, suggesting a central role of self-pMHC recognition. DC-mediated SFK activation leads to "TCR licensing," a process that dramatically increases sensitivity and magnitude of the TCR response to cognate pMHC. Thus, TCR licensing, besides costimulation, is a main mechanism of DCs to present Ag effectively.
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Affiliation(s)
- Paul Meraner
- Research Center for Molecular Medicine, Austrian Academy of Sciences
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14
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Carinci F, Palmieri A, Perrotti V, Piattelli A, Cenzi R, Brunell G, Martinelli M, Arlotti M, Pezzetti F. Genetic Effects of Medpor® on Osteoblast-like Cells. J Craniofac Surg 2006; 17:1243-50. [PMID: 17119439 DOI: 10.1097/01.scs.0000248644.02718.28] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Porous polyethylene (PP or Medpor) is an alloplastic material used worldwide for craniofacial reconstruction. Although several clinical studies are available, there is a lack as regard the genetic effects. Because PP is always fixed on bone and the mechanism by which PP acts on osteoblasts is unknown, we therefore attempted to address this question by using microarray techniques to identify genes that are differently regulated in osteoblasts exposed to PP. By using DNA microarrays containing 19,200 genes, we identified in osteoblast-like cell lines (i.e. MG-63) cultured on PP several genes where expression was differentially regulated. The differentially expressed genes cover a broad range of functional activities: 1) signal transduction, 2) transcription, 3) translation, 4) cell cycle regulation, 5) vesicular transport, and 6) production of cytoskeletal elements, cell-adhesion molecules and extracellular matrix components. The data reported are, to our knowledge, the first genetic portrait of osteoblast-like cells cultured on PP. They are relevant to better understanding of the molecular mechanism of bone-PP interaction and as a model for comparing other materials used for bone reconstruction.
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15
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Myers MD, Dragone LL, Weiss A. Src-like adaptor protein down-regulates T cell receptor (TCR)-CD3 expression by targeting TCRzeta for degradation. ACTA ACUST UNITED AC 2005; 170:285-94. [PMID: 16027224 PMCID: PMC2171412 DOI: 10.1083/jcb.200501164] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Src-like adaptor protein (SLAP) down-regulates expression of the T cell receptor (TCR)–CD3 complex during a specific stage of thymocyte development when the TCR repertoire is selected. Consequently, SLAP−/− thymocytes display alterations in thymocyte development. Here, we have studied the mechanism of SLAP function. We demonstrate that SLAP-deficient thymocytes have increased TCRζ chain expression as a result of a defect in TCRζ degradation. Failure to degrade TCRζ leads to an increased pool of fully assembled TCR–CD3 complexes that are capable of recycling back to the cell surface. We also provide evidence that SLAP functions in a pathway that requires the phosphorylated TCRζ chain and the Src family kinase Lck, but not ZAP-70 (ζ-associated protein of 70 kD). These studies reveal a unique mechanism by which SLAP contributes to the regulation of TCR expression during a distinct stage of thymocyte development.
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MESH Headings
- Animals
- Cell Line, Tumor
- Down-Regulation
- Humans
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphorylation
- Protein Binding
- Protein-Tyrosine Kinases/metabolism
- Proto-Oncogene Proteins pp60(c-src)/genetics
- Proto-Oncogene Proteins pp60(c-src)/metabolism
- Receptor-CD3 Complex, Antigen, T-Cell/biosynthesis
- Receptor-CD3 Complex, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Antigen, T-Cell/genetics
- Signal Transduction
- T-Lymphocytes/physiology
- ZAP-70 Protein-Tyrosine Kinase
- src Homology Domains
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Affiliation(s)
- Margaret D Myers
- Department of Medicine, Rosalind Russell Medical Research Center for Arthritis, University of California, San Francisco, CA 94143, USA
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16
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Szymczak AL, Workman CJ, Gil D, Dilioglou S, Vignali KM, Palmer E, Vignali DAA. The CD3ε Proline-Rich Sequence, and Its Interaction with Nck, Is Not Required for T Cell Development and Function. THE JOURNAL OF IMMUNOLOGY 2005; 175:270-5. [PMID: 15972658 DOI: 10.4049/jimmunol.175.1.270] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The CD3epsilon proline-rich sequence (PRS) binds to the cytosolic adaptor molecule Nck after TCR ligation. It has been proposed that this interaction is essential for immunological synapse formation and T cell activation. To assess the physiological importance of the CD3epsilon PRS, we have generated mice that lack this motif (CD3epsilon.PRS(M)). Pull-down experiments demonstrated the inability of Nck to bind to the CD3epsilon PRS in thymocytes from mutant mice after TCR ligation. Surprisingly, no differences were observed in the number and percentage of T cell subsets in the thymus and spleen, and there was no apparent defect in positive or negative selection. Furthermore, the proliferative response of CD3epsilon.PRS(M) T cells to staphylococcal enterotoxin B and anti-CD3 Ab was normal. TCR surface expression, constitutive internalization, and Ag-induced down-modulation were also normal. These data suggest that the interaction between the CD3epsilon PRS and Nck, or any other Src homology 3 domain-containing molecule, is not essential for T cell development and function.
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Affiliation(s)
- Andrea L Szymczak
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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