Abstract
Activation-induced cell death (AICD) is a mechanism of peripheral T cell tolerance that depends upon an interaction between Fas and Fas ligand (FasL). Although c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) may be involved in apoptosis in various cell types, the mode of regulation of FasL expression during AICD in T cells by these two MAPKs is incompletely understood. To investigate the regulatory roles of these two MAPKs, we analyzed the kinetics of TCR-induced p38 MAPK and JNK activity and their regulation of FasL expression and AICD. We report that both JNK and p38 MAPK regulate AICD in T cells. Our data suggest a novel model of T cell AICD in which p38 MAPK acts early to initiate FasL expression and the Fas-mediated activation of caspases. Subsequently, caspases stimulate JNK to further upregulate FasL expression. Thus, p38 MAPK and downstream JNK converge to regulate FasL expression at different times after T cell receptor stimulation to elicit maximum AICD.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis / drug effects
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Apoptosis / genetics
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Apoptosis / immunology*
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Calcium-Calmodulin-Dependent Protein Kinases / physiology*
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Caspase Inhibitors
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Caspases / metabolism
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Cell Line
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Enzyme Activation / drug effects
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Enzyme Inhibitors / pharmacology
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Fas Ligand Protein
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Hybridomas
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Imidazoles / pharmacology
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JNK Mitogen-Activated Protein Kinases
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Ligands
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Lymphocyte Activation / drug effects
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Lymphocyte Activation / genetics
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Lymphocyte Activation / immunology*
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Membrane Glycoproteins / biosynthesis*
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Membrane Glycoproteins / deficiency
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism
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Mice
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Mice, Inbred C3H
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Mice, Inbred C57BL
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Mice, Mutant Strains
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Mitogen-Activated Protein Kinases / metabolism
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Mitogen-Activated Protein Kinases / physiology*
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Pyridines / pharmacology
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T-Lymphocytes / cytology
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T-Lymphocytes / enzymology*
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T-Lymphocytes / immunology*
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fas Receptor / metabolism*
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p38 Mitogen-Activated Protein Kinases
Substances
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Caspase Inhibitors
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Enzyme Inhibitors
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Fas Ligand Protein
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Fasl protein, mouse
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Imidazoles
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Ligands
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Membrane Glycoproteins
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Pyridines
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fas Receptor
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Calcium-Calmodulin-Dependent Protein Kinases
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases
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Caspases
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SB 203580