Figure 2: Inhibition of death pathways by serpins. Stimulation of death receptors leads to the activation of caspase 8 and the rupture of the mitochondria and release of cytochrome c, which activates the caspase 9/3 pathway of apoptosis. Multiple stimuli trigger the release of cathepsins from the lysosome into the cytoplasm. More extensive release results in necrotic PCD, whereas limited release triggers the mitochondrial pathway of apoptosis through Bid cleavage. GrB can trigger apoptotic PCD through the activation of caspase 3 or direct entry into the nucleus. SerpinsIC specific for executioner proteases are indicated.