FIGURE 2

Caspase inhibition by IAPs. (a) XIAP can bind to the processed end of the large subunit of caspase 9 thereby preventing its dimerization and subsequent activation. XIAP can also bind to the active catalytic sites (solid circles) of effector caspases, caspase 3/7, thereby blocking their activity. (b) DIAP1 neutralizes DRONC by binding to its pro-domain (hatched box) resulting in DIAP1-RING-dependent degradation of DRONC. DIAP1 can also bind to the processed ends of effector caspases, DrICE and DCP1, but may or may not inhibit their activity (indicated with a dashed line). See text for details