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Cell Death Differ. 2007 Jun;14(6):1086-94. Epub 2007 Mar 2.

Inhibiting Drp1-mediated mitochondrial fission selectively prevents the release of cytochrome c during apoptosis.

Author information

1
Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.

Abstract

Most cell death stimuli trigger the mitochondrial release of cytochrome c and other cofactors that induce caspase activation and ensuing apoptosis. Apoptosis is also associated with massive mitochondrial fragmentation and cristae remodeling. Dynamin-related protein 1 (Drp1), a protein of the mitochondrial fission machinery, has been reported to participate in apoptotic mitochondrial fragmentation. Several theories explaining the mechanisms of cytochrome c release have been proposed. One suggests that it relies on the activation of Drp1-mediated mitochondrial fission. Here, we report that downregulation of Drp1 inhibits fragmentation of the mitochondrial network and partially prevents the release of cytochrome c but fails to prevent the release of other mitochondrial factors such as second mitochondria-derived activator of caspase/direct IAP-binding protein with low pI, Omi/HtrA2, adenylate kinase 2 and deafness dystonia peptide/TIMM8a. An explanation for the prevention of cytochrome c release is provided by our observation that inhibiting Drp1-mediated mitochondrial fission prevents the mitochondrial release of soluble OPA1 that was proposed to regulate cristae remodeling and complete cytochrome c release during apoptosis. Finally, we observed that downregulation of Drp1 delays but does not inhibit apoptosis, suggesting that mitochondrial fragmentation is not a prerequisite for apoptosis.

PMID:
17332775
DOI:
10.1038/sj.cdd.4402107
[Indexed for MEDLINE]
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