The adaptor molecule FADD is required for cleavage of Bid following reovirus infection of HEK293 cells [16] . Based on these data, we hypothesized that caspase-8 activity as a consequence of extrinsic prodeath signaling, is required for cleavage and activation of Bid. To test this hypothesis, we assessed the capacity of reovirus to mediate Bid cleavage in L929 cells treated with caspase-8 inhibitor Z-IETD-FMK ( Figure 1B ). As anticipated, Bid cleavage was not observed in mock-infected cells or mock-infected cells treated with Z-IETD-FMK (data not shown). Although tBid was generated at 36-48 h following reovirus infection of vehicle-treated cells, reovirus failed to efficiently induce activation of Bid in Z-IETD-FMK-treated cells until 48 h post-infection, providing evidence that reovirus evokes cleavage of Bid via caspase-8. In response to a variety of death agonists, Bid amplifies death signaling by linking the extrinsic (caspase-8) and intrinsic (caspase-9) apoptotic pathways [30] . Since our findings with reovirus parallel this pattern, our results suggest that Bid functions similarly following reovirus infection by linking the death-receptor and mitochondrial apoptotic pathways.