Caspase 9 (CASP9)

The aspartic acid specific protease caspase-9 has been linked to the mitochondrial death pathway. It is activated during programmed 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.

Caspase-9 is a member of the cysteine-aspartic acid protease (caspase) family. This protein is processed by caspase APAF1; this step is thought to be one of the earliest in the caspase activation cascade. Alternative splicing results in two transcript variants which encode different isoforms.