What are the types of caspases?

Caspases are classified into 3 categories: initiator caspases (caspase 2,8,9, and 10) , executioner caspases (caspase 3, 6, and 7), and inflammatory caspases (1,4, 5, 11, and 12). Initiator caspases are responsible for initiating apoptosis and they are activated by dimerization. Dimerization is regulated by binding to adaptor proteins through protein-protein interaction of death folds (a tertiary structure motif). Executioner caspases carry out the mass proteolysis that leads to apoptosis. These caspases can cleave a wide range of target proteins leading to apoptosis. Caspase-activated DNase (CAD/DFF40) is the main nuclease responsible for apoptotic DNA fragmentation. Inflammatory caspases do not function in apoptosis and instead are involved in inflammatory cytokine signaling, danger signals and other types of cell death like pyroptosis. Thus, these caspases play a key role in innate immune response by inducing pyroptosis to stop intracellular replication of pathogens.