Description Caspase-9 (ICE-LAP6, Mch-6, Apaf-3) is a member of the cysteine aspartic acid protease, or caspase, family. Pro-Caspase-9 exists as a 46 kDa isomer that is cleaved by apoptotic stimulation, and functions as the major initiator caspase in programmed cell death, or apoptosis (1-4). Upon stimulation, cytochrome c is released from mitochondria, and associates with the Pro-Caspase-9/Apaf 1 complex. This complex in turn activates Pro-Caspase-9 by cleaving it into an active 35 kDa fragment and a small 10 kDa fragment (1,2). Activated Caspase-9 cleaves Caspase-3 as well as poly (ADP-ribose) polymerase (PARP) to initiate a caspase cascade and apoptosis (3,4). |