Abstract
The goal of this study was to identify the host cellular proteins interacting with the 3C protein of enterovirus 71. 3C was found to interact with mitochondrial cytochrome c oxidase subunitⅡ（COXⅡ）in the use of yeast two hybrid system from human brain cDNA library. COXⅡ, a subunit of mitochondrial complex Ⅳ, is the acceptor of electrons from ferrocytochrome c. 3C-green fluorescent protein（GFP）fusion protein was found to localized on the mitochondria by confocal microscopy. After transient expression of 3C protein, the release of cytochrome c and the activation of caspase 9 and caspase 3 occurred. On the other hand, cytochrome c was released to the cytoplasm at 6 hour post-infection. Caspase 9 and caspase 3 were also activated after 12 hours. Our findings suggest that the 3C protein is responsible for triggering apoptosis in the SF268 cells by releasing of cytochrome c to the cytoplasm, and than activating caspase 9 and caspase 3, which may play an important role in the pathogenesis of EV71 infection.