Abstract
Fas and Fas-associated death domain (FADD) play a critical role in the homeostasis of different cell types. The regulation of Fas and FADD-mediated cell death is pivotal to many physiological functions. The activation of T lymphocytes by concanavalin A (Con A) inhibited Fas-mediated cell death. We identified that among the several activation signals downstream of Con A stimulation, mitogen-activated protein (MAP) kinase kinase (MKK) was the major kinase pathway that antagonized Fas-triggered cell death. MKK1 suppressed FADD- but not caspase-3- induced apoptosis, indicating that antagonism occurred early along the Fas-initiated apoptotic cascade. We further demonstrated that activation of MKK1 led to expression of FLIP, a specific inhibitor of FADD. MKK1 inhibition of FADD-induced cell death was abrogated if induction of FLIP was prevented, indicating that FLIP mediates MKK1 suppression of FADD-mediated apoptosis. Our results illustrate a general mechanism by which activation of MAP kinase attenuates apoptotic signals initiated by death receptors in normal and transformed cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Apoptosis / physiology*
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CASP8 and FADD-Like Apoptosis Regulating Protein
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Carrier Proteins / metabolism*
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Caspase 3
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Caspase 8
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Caspase 9
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Caspases / metabolism*
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Concanavalin A / pharmacology
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Fas-Associated Death Domain Protein
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Humans
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Intracellular Signaling Peptides and Proteins*
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Jurkat Cells
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MAP Kinase Kinase 1
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Mitogen-Activated Protein Kinase Kinases*
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Oligonucleotides, Antisense / pharmacology
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Protein Serine-Threonine Kinases / metabolism*
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Protein-Tyrosine Kinases / metabolism*
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Receptors, Tumor Necrosis Factor / metabolism
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Signal Transduction / physiology
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T-Lymphocytes / metabolism*
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Transfection / genetics
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fas Receptor / metabolism*
Substances
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Adaptor Proteins, Signal Transducing
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CASP8 and FADD-Like Apoptosis Regulating Protein
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CFLAR protein, human
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Carrier Proteins
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FADD protein, human
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Fas-Associated Death Domain Protein
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Intracellular Signaling Peptides and Proteins
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Oligonucleotides, Antisense
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Receptors, Tumor Necrosis Factor
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fas Receptor
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Concanavalin A
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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Mitogen-Activated Protein Kinase Kinases
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CASP3 protein, human
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CASP8 protein, human
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CASP9 protein, human
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Caspase 3
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Caspase 8
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Caspase 9
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Caspases