Abstract
Persistent c-Jun NH2-terminal kinase (JNK) activation induces cell death. Different mechanisms are ascribed to JNK-induced cell death. Most of the JNK-apoptosis studies employ stress stimuli known to activate kinases other than JNK. Here we used overexpression of mitogen-activated protein kinase kinase 7 (MKK7) to activate selectively JNK in T lymphoma Jurkat cells. Similar to that reported previously, Fas ligand (FasL) expression was up-regulated by JNK activation. Dominant negative-FADD and caspase-8 inhibitor benzyloxycarbonyl-Ile-Glu-Thr-Asp effectively inhibited MKK7-induced cell death, supporting a major involvement of FADD cascade. However, MKK7-induced cell death was not prevented by antagonist antibody ZB4 and Fas-Fc, indicating that Fas-FasL interaction is minimally involved. Confocal microscopy revealed that persistent JNK activation led to clustering of Fas. Our results suggest that, in contrast to that reported previously, JNK alone-induced death in Jurkat cells is FADD-dependent but is not triggered by Fas-FasL interaction.
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*
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Carrier Proteins / physiology*
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Caspase 8
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Caspase 9
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Caspase Inhibitors
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Enzyme Activation
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Fas Ligand Protein
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Fas-Associated Death Domain Protein
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Humans
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JNK Mitogen-Activated Protein Kinases
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Jurkat Cells
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MAP Kinase Kinase 7
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MAP Kinase Kinase Kinase 1*
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Membrane Glycoproteins / physiology*
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Mitogen-Activated Protein Kinase Kinases / physiology
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Mitogen-Activated Protein Kinases / physiology*
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Protein Serine-Threonine Kinases / physiology
Substances
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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Caspase Inhibitors
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FADD protein, human
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FASLG protein, human
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Fas Ligand Protein
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Fas-Associated Death Domain Protein
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Membrane Glycoproteins
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Protein Serine-Threonine Kinases
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase Kinase 1
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MAP3K1 protein, human
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MAP Kinase Kinase 7
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MAP2K7 protein, human
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Mitogen-Activated Protein Kinase Kinases
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CASP8 protein, human
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CASP9 protein, human
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Caspase 8
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Caspase 9