Caspase-9

Caspase-9 is an initiator caspase.

The aspartic acid specific protease caspase-9 has been linked to the mitochondrial death pathway. It is activated during programed cell death (apoptosis). Induction of stress signalling pathways JNK/SAPK causes release of cytochrome c from mitochondria and activation of apaf-1 (apoptosome), which in turn cleaves the pro-enzyme of caspase-9 into the active form.

Once intiated caspase-9 goes on to cleave procaspase-3 & procaspase-7 and which cleave several cellular targets, including poly ADP ribose polymerase.