Loss of OPA1 Perturbates the Mitochondrial Inner Membrane Structure and Integrity, Leading to Cytochrome c Release and Apoptosis
| Autor: | Laurent Baricault, Pascale Belenguer, Annie Valette, Guy Lenaers, Emmanuelle Guillou, Aurélien Olichon, Nicole Gas |
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| Rok vydání: | 2003 |
| Předmět: |
endocrine system
Mitochondrial membrane fusion Apoptosis Cytochrome c Group Intracellular Membranes Cell Biology Biology medicine.disease Biochemistry Mitochondrial apoptosis-induced channel Retinal ganglion eye diseases GTP Phosphohydrolases Mitochondria Cell biology Microscopy Electron Mitochondrial inner membrane fusion Translocase of the inner membrane Tumor Cells Cultured medicine Humans Optic Atrophy 1 ATP–ADP translocase Inner mitochondrial membrane Molecular Biology |
| Zdroj: | Journal of Biological Chemistry. 278:7743-7746 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.c200677200 |
| Popis: | OPA1 encodes a large GTPase related to dynamins, anchored to the mitochondrial cristae inner membrane, facing the intermembrane space. OPA1 haplo-insufficiency is responsible for the most common form of autosomal dominant optic atrophy (ADOA, MIM165500), a neuropathy resulting from degeneration of the retinal ganglion cells and optic nerve atrophy. Here we show that down-regulation of OPA1 in HeLa cells using specific small interfering RNA (siRNA) leads to fragmentation of the mitochondrial network concomitantly to the dissipation of the mitochondrial membrane potential and to a drastic disorganization of the cristae. These events are followed by cytochrome c release and caspase-dependent apoptotic nuclear events. Similarly, in NIH-OVCAR-3 cells, the OPA1 siRNA induces mitochondrial fragmentation and apoptosis, the latter being inhibited by Bcl2 overexpression. These results suggest that OPA1 is a major organizer of the mitochondrial inner membrane from which the maintenance of the cristae integrity depends. As loss of OPA1 commits cells to apoptosis without any other stimulus, we propose that OPA1 is involved in the cytochrome c sequestration and might be a target for mitochondrial apoptotic effectors. Our results also suggest that abnormal apoptosis is a possible pathophysiological process leading to the retinal ganglion cells degeneration in ADOA patients. |
| Databáze: | OpenAIRE |
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