APAF-1: Proteins and Enzymes

APAF-1, the human homolog of C. elegans CED-4, is a 130 kDa cytosolic protein that participates in the Cytochrome c-dependent activation of Caspase-3. The intrinsic Caspase activation pathway is activated by the release of mitochondrial Cytochrome c. This induces the cytosolic assembly of the apoptosome, a Caspase-activation complex involving Cytochrome c, APAF-1, and Caspase-9. Once activated, Caspase-9 can initiate a biochemical cascade involving activation of the downstream executioner Caspases-3, -6, and-7.