Abstract
BID, a pro-apoptotic Bcl-2 family member, promotes cytochrome c release during apoptosis initiated by CD95L or TNF. Activation of caspase-8 in the latter pathways results in cleavage of BID, translocation of activated BID to mitochondria, followed by redistribution of cytochrome c to the cytosol. However, it is unclear whether BID participates in cytochrome c release in other (non-death receptor) cell death pathways. Here, we show that BID is cleaved in response to multiple death-inducing stimuli (staurosporine, UV radiation, cycloheximide, etoposide). However BID cleavage in these contexts was blocked by Bcl-2, suggesting that proteolysis of BID occurred distal to cytochrome c release. Furthermore, addition of cytochrome c to Jurkat post-nuclear extracts triggered breakdown of BID at Asp-59 which was catalysed by caspase-3 rather than caspase-8. We provide evidence that caspase-3 catalysed cleavage of BID represents a feedback loop for the amplification of mitochondrial cytochrome c release during cytotoxic drug and UV radiation-induced apoptosis.
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* / radiation effects
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Aspartic Acid / metabolism
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BH3 Interacting Domain Death Agonist Protein
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Carrier Proteins / metabolism*
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Caspase 3
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Caspases / metabolism*
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Catalysis
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Cell-Free System
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Cycloheximide / pharmacology
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Cytochrome c Group / metabolism*
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Enzyme Inhibitors / pharmacology
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Etoposide / pharmacology
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Humans
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Jurkat Cells
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Mice
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Mitochondria, Liver / drug effects
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Mitochondria, Liver / metabolism*
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Nucleic Acid Synthesis Inhibitors / pharmacology
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Protein Synthesis Inhibitors / pharmacology
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Proto-Oncogene Proteins c-bcl-2 / metabolism*
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Staurosporine / pharmacology
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Tumor Cells, Cultured
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Ultraviolet Rays
Substances
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BH3 Interacting Domain Death Agonist Protein
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BID protein, human
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Bid protein, mouse
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Carrier Proteins
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Cytochrome c Group
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Enzyme Inhibitors
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Nucleic Acid Synthesis Inhibitors
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Protein Synthesis Inhibitors
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Proto-Oncogene Proteins c-bcl-2
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Aspartic Acid
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Etoposide
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Cycloheximide
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CASP3 protein, human
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Casp3 protein, mouse
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Caspase 3
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Caspases
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Staurosporine