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Thaker YR, Raab M, Strebhardt K, Rudd CE. GTPase-activating protein Rasal1 associates with ZAP-70 of the TCR and negatively regulates T-cell tumor immunity. Nat Commun 2019; 10:4804. [PMID: 31641113 PMCID: PMC6805919 DOI: 10.1038/s41467-019-12544-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 09/09/2019] [Indexed: 12/11/2022] Open
Abstract
Immunotherapy involving checkpoint blockades of inhibitory co-receptors is effective in combating cancer. Despite this, the full range of mediators that inhibit T-cell activation and influence anti-tumor immunity is unclear. Here, we identify the GTPase-activating protein (GAP) Rasal1 as a novel TCR-ZAP-70 binding protein that negatively regulates T-cell activation and tumor immunity. Rasal1 inhibits via two pathways, the binding and inhibition of the kinase domain of ZAP-70, and GAP inhibition of the p21ras-ERK pathway. It is expressed in activated CD4 + and CD8 + T-cells, and inhibits CD4 + T-cell responses to antigenic peptides presented by dendritic cells as well as CD4 + T-cell responses to peptide antigens in vivo. Furthermore, siRNA reduction of Rasal1 expression in T-cells shrinks B16 melanoma and EL-4 lymphoma tumors, concurrent with an increase in CD8 + tumor-infiltrating T-cells expressing granzyme B and interferon γ-1. Our findings identify ZAP-70-associated Rasal1 as a new negative regulator of T-cell activation and tumor immunity. Activation of T cells in the tumor microenvironment can be inhibited through a variety of mechanisms. Here, the authors show that Rasal1, a GTPase-activating protein, binds and inhibits signaling downstream of the T Cell Receptor complex and that consistently, its reduced expression enhances anti-tumor T-cell responses in two syngeneic cancer mouse models.
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Affiliation(s)
- Youg Raj Thaker
- Cell Signalling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.,School of Biological Science, Protein Structure and Disease Mechanisms, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Monika Raab
- Department of Obstetrics and Gynaecology, School of Medicine, J.W. Goethe-University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Klaus Strebhardt
- Department of Obstetrics and Gynaecology, School of Medicine, J.W. Goethe-University, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
| | - Christopher E Rudd
- Cell Signalling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK. .,Département de Immunologie-Oncologie, Centre de Recherche Hôpital Maisonneuve-Rosemont, Montreal, QC, H1T 2M4, Canada. .,Département de Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
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Yang J, Huang Y, Wang XB, Becker FF, Gascoyne PR. Differential analysis of human leukocytes by dielectrophoretic field-flow-fractionation. Biophys J 2000; 78:2680-9. [PMID: 10777764 PMCID: PMC1300857 DOI: 10.1016/s0006-3495(00)76812-3] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The differential analysis of human leukocytes has many important biological and medical applications. In this work, dielectrophoretic field-flow-fractionation (DEP-FFF), a cell-separation technique that exploits the differences in the density and dielectric properties of cells, was used to separate the mixtures of the major human leukocyte subpopulations (T- and B-lymphocytes, monocytes, and granulocytes). The separation was conducted in a thin chamber equipped with an array of microfabricated interdigitated electrodes on the bottom surface, and the separation performance was characterized by on-line flow cytometry. To investigate optimal separation conditions for different leukocyte mixtures, elution fractograms at various DEP field frequencies were obtained for each leukocyte subtype. With appropriately chosen conditions, high separation performance was achieved in separating T- (or B-) lymphocytes from monocytes, T- (or B-) lymphocytes from granulocytes, and monocytes from granulocytes. DEP-FFF does not involve cell-labeling or cell-modification step, and provides a new approach to hematological analysis.
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Affiliation(s)
- J Yang
- Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
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Tonnetti L, Verí MC, Bonvini E, D'Adamio L. A role for neutral sphingomyelinase-mediated ceramide production in T cell receptor-induced apoptosis and mitogen-activated protein kinase-mediated signal transduction. J Exp Med 1999; 189:1581-9. [PMID: 10330437 PMCID: PMC2193632 DOI: 10.1084/jem.189.10.1581] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Studying apoptosis induced by T cell receptor (TCR) cross-linking in the T cell hybridoma, 3DO, we found both neutral sphingomyelinase activation and production of ceramide upon receptor engagement. Pharmacological inhibition of ceramide production by the fungal toxin, fumonisin B1, impaired TCR-induced interleukin (IL)-2 production and programmed cell death. Addition of either exogenous ceramide or bacterial sphingomyelinase reconstituted both responses. Moreover, specific inactivation of neutral sphingomyelinase by antisense RNA inhibited IL-2 production and mitogen-activated protein kinase activation after TCR triggering. These results suggest that ceramide production by activation of neutral sphingomyelinase is an essential component of the TCR signaling machinery.
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Affiliation(s)
- L Tonnetti
- T-Cell Apoptosis Unit, Laboratory of Cellular and Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Lake DF, Helgerson S, Landsperger WJ, Marchalonis JJ. Physical and epitope analysis of a recombinant human T-cell receptor V alpha/V beta construct support the similarity to immunoglobulin. JOURNAL OF PROTEIN CHEMISTRY 1997; 16:309-20. [PMID: 9188070 DOI: 10.1023/a:1026361110795] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The genetic organization and protein structure of T-cell receptors (TCR) and immunoglobulins (Ig) are remarkably similar. Through recombinant, physical, and peptide-based immunological studies we demonstrated that rabbit antisera generated against a recombinant single-chain TCR (scTCR) react with defined peptide epitopes of their constituent TCR alpha and beta chains. These antisera cross-react with the lambda light-chain Mcg as well as with peptides duplicating its covalent structure. Conversely, rabbit antisera generated to human lambda light chains cross-reacted with the recombinant scTCR. Rabbit anti-lambda antibodies purified on an scTCR affinity column bound to T-cell lines and to T and B lymphocytes from peripheral blood. Circular dichroism analysis demonstrated plots characteristic of beta-sheets for both Mcg and recombinant scTCR. Antisera directed against TCR alpha-chain synthetic peptides reacted with scTCR, Mcg lambda light-chain protein, synthetic peptides from regions of sequence homology in beta-chains, and Mcg. Based upon this homology and the serological cross-reactions which reflect conformational determinants, we suggest that the V alpha/V beta antigen-binding domain of this particular monoclonal scTCR construct is substantially similar to the conformational structure of lambda light chains.
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MESH Headings
- Amino Acid Sequence
- Animals
- Circular Dichroism
- Cross Reactions
- Flow Cytometry
- Humans
- Immune Sera/chemistry
- Immunodominant Epitopes/analysis
- Immunodominant Epitopes/metabolism
- Immunoglobulin lambda-Chains/chemistry
- Immunoglobulin lambda-Chains/immunology
- Immunoglobulin lambda-Chains/metabolism
- Immunoglobulins/analysis
- Jurkat Cells
- Molecular Sequence Data
- Peptides/immunology
- Rabbits
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Recombinant Proteins/analysis
- Spectrometry, Fluorescence
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Affiliation(s)
- D F Lake
- Department of Microbiology and Immunology, University of Arizona, Tucson 85724, USA
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