Fig. 4.

Regulated Cell Death Pathways. The schematics illustrate the involvement of cysteine proteases in most regulated cell death pathways, with the exception of NETosis, which requires the serine protease neutrophil elastase. Different sets of caspases are important for either apoptotic or pyroptotic cell death. In addition to its role in initiating the extrinsic pathway of apoptosis, caspase-8 regulates necroptosis by forming a complex with the pseudocaspase FLIP. Although the story is still quite murky in humans, regulated necrosis has been shown in C. elegans to depend on calpains and lysosomal cathepsins.