Abstract
The mechanism during apoptosis by which cytochrome c is rapidly and completely released in the absence of mitochondrial swelling is uncertain. Here, we show that two distinct pathways are involved. One mediates release of cytochrome c across the outer mitochondrial membrane, and another, characterized in this study, is responsible for the redistribution of cytochrome c stored in intramitochondrial cristae. We have found that the "BH3-only" molecule tBID induces a striking remodeling of mitochondrial structure with mobilization of the cytochrome c stores (approximately 85%) in cristae. This reorganization does not require tBID's BH3 domain and is independent of BAK, but is inhibited by CsA. During this process, individual cristae become fused and the junctions between the cristae and the intermembrane space are opened.
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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Adenylate Kinase / metabolism
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Animals
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Apoptosis / physiology*
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BH3 Interacting Domain Death Agonist Protein
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Carrier Proteins / metabolism
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Carrier Proteins / pharmacology
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Cells, Cultured
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Cyclosporine / pharmacology
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Cytochrome c Group / metabolism*
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Enzyme Inhibitors / pharmacology
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Intracellular Membranes / metabolism
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Mice
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Mice, Inbred BALB C
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Microscopy, Electron
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Mitochondria, Liver / drug effects
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Mitochondria, Liver / metabolism*
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Mitochondria, Liver / ultrastructure*
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Mutation / physiology
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-bcl-2*
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bcl-2 Homologous Antagonist-Killer Protein
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bcl-2-Associated X Protein
Substances
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BH3 Interacting Domain Death Agonist Protein
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Bak1 protein, mouse
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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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Membrane Proteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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bcl-2 Homologous Antagonist-Killer Protein
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bcl-2-Associated X Protein
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Cyclosporine
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Adenylate Kinase