FIG. 8.

Schematic illustration of the CVB2O-induced apoptotic response in RD cells. Cytolytic CVB2O infection (vVP1Q164K) of RD cells results in activation of both the extrinsic (procaspase-8) and intrinsic (procaspase-9) pathways. These pathways are interconnected by Bid. When Bid is proteolytically activated by caspase-8, it translocates to the mitochondria and induces cytochrome c release. This, in turn, causes a successive activation of caspase-9 and caspase-3. The activated apoptotic signal eventually results in apoptotic cell death. In contrast, CVB2Owt causes a persistent infection in RD cells without detectable signs of apoptosis.