Figure 1.

The apoptosis pathway in Drosophila. In living cells, the Caspase-9-like initiator caspase Dronc is inhibited by Drosophila inhibitor of apoptosis protein 1 (Diap1). Apoptosis is induced by activation of the IAP-antagonists Reaper, Hid, and Grim that induce ubiquitylation and degradation of Diap1. Dronc is released from Diap1 inhibition and forms the apoptosome holoenzyme together with the adaptor protein Ark. Dronc is activated in this complex, thereby proteolytically activating effector caspases DrICE and Dcp-1 causing apoptosis. The Baculovirus caspase inhibitor P35 acts specifically on DrICE and Dcp-1.