Abstract
Smac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Previous studies have shown that c-Jun NH(2)-terminal kinase (JNK) is involved in regulating another mitochondrial protein, cytochrome c during apoptosis; however, the role of JNK in the release of mitochondrial Smac is unknown. Here we show that induction of apoptosis in multiple myeloma (MM) cells is associated with activation of JNK, translocation of JNK from cytosol to mitochondria, and release of Smac from mitochondria to cytosol. Blocking JNK either by dominant-negative mutant (DN-JNK) or cotreatment with a specific JNK inhibitor, SP600125, abrogates both stress-induced release of Smac and induction of apoptosis. These findings demonstrate that activation of JNK is an obligatory event for the release of Smac during stress-induced apoptosis in MM cells.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Anthracenes / pharmacology
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Apoptosis Regulatory Proteins
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Apoptosis*
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Blotting, Western
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Carrier Proteins / metabolism*
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Cell Line
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Coloring Agents / pharmacology
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Cytochrome c Group / metabolism
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Cytosol / metabolism
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DNA, Complementary / metabolism
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Dose-Response Relationship, Drug
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Enzyme Inhibitors / pharmacology
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Genes, Dominant
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Green Fluorescent Proteins
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Humans
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Immunoblotting
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Intracellular Signaling Peptides and Proteins
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JNK Mitogen-Activated Protein Kinases*
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Luminescent Proteins / metabolism
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MAP Kinase Kinase 4
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Membrane Potentials
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Mitochondria / metabolism
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Mitochondrial Proteins / metabolism*
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Mitogen-Activated Protein Kinase Kinases / metabolism*
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Models, Biological
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Multiple Myeloma / enzymology
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Multiple Myeloma / pathology*
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Serine / metabolism
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Tetrazolium Salts / pharmacology
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Thiazoles / pharmacology
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Time Factors
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Transfection
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Tumor Cells, Cultured
Substances
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Anthracenes
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Apoptosis Regulatory Proteins
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Carrier Proteins
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Coloring Agents
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Cytochrome c Group
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DIABLO protein, human
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DNA, Complementary
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Enzyme Inhibitors
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Intracellular Signaling Peptides and Proteins
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Luminescent Proteins
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Mitochondrial Proteins
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Tetrazolium Salts
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Thiazoles
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Green Fluorescent Proteins
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pyrazolanthrone
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Serine
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JNK Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 4
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Mitogen-Activated Protein Kinase Kinases
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thiazolyl blue