Mitochondrial dysfunction in lyssavirus-induced apoptosis.
Lyssaviruses are highly neurotropic viruses associated with neuronal apoptosis. Previous observations have indicated that the matrix proteins (M) of some lyssaviruses induce strong neuronal apoptosis. However, the molecular mechanism(s) involved in this phenomenon is still unknown. We show that for Mokola virus (MOK), a lyssavirus of low pathogenicity, the M (M-MOK) targets mitochondria, disrupts the mitochondrial morphology, and induces apoptosis. Our analysis of truncated M-MOK mutants suggests that the information required for efficient mitochondrial targeting and dysfunction, as well as caspase-9 activation and apoptosis, is held between residues 46 and 110 of M-MOK. We used a yeast two-hybrid approach, a coimmunoprecipitation assay, and confocal microscopy to demonstrate that M-MOK physically associates with the subunit I of the cytochrome c (cyt-c) oxidase (CcO) of the mitochondrial respiratory chain; this is in contrast to the M of the highly pathogenic Thailand lyssavirus (M-THA). M-MOK expression induces a significant decrease in CcO activity, which is not the case with M-THA. M-MOK mutations (K77R and N81E) resulting in a similar sequence to M-THA at positions 77 and 81 annul cyt-c release and apoptosis and restore CcO activity. As expected, the reverse mutations, R77K and E81N, introduced in M-THA induce a phenotype similar to that due to M-MOK. These features indicate a novel mechanism for energy depletion during lyssavirus-induced apoptosis.
Gholami
Alireza
A
Unité Postulante de Recherche et d'Expertise Dynamique des Lyssavirus et Adaptation à l'Hôte, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
Kassis
Raïd
R
Real
Eléonore
E
Delmas
Olivier
O
Guadagnini
Stéphanie
S
Larrous
Florence
F
Obach
Dorothée
D
Prevost
Marie-Christine
MC
Jacob
Yves
Y
Bourhy
Hervé
H
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D053453:Caspase 9 / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D018114:Lyssavirus / Q000235:genetics / Q000472:pathogenicity*; D051379:Mice; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000502:physiology* / Q000821:virology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D014764:Viral Proteins; D003576:Electron Transport Complex IV; D053453:Caspase 9