Thiol protease that acts as a major effector caspase involved in the execution phase of apoptosis . Following cleavage and activation by initiator caspases (CASP8, CASP9 and/or CASP10), mediates execution of apoptosis by catalyzing cleavage of many proteins . At the onset of apoptosis, it proteolytically cleaves poly(ADP-ribose) polymerase PARP1 at a '216-Asp--Gly-217' bond . Cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain (By similarity). Cleaves and activates caspase-6, -7 and -9 (CASP6, CASP7 and CASP9, respectively). Cleaves and inactivates interleukin-18 (IL18). Involved in the cleavage of huntingtin . Triggers cell adhesion in sympathetic neurons through RET cleavage . Cleaves and inhibits serine/threonine-protein kinase AKT1 in response to oxidative stress . Acts as an inhibitor of type I interferon production during virus-induced apoptosis by mediating cleavage of antiviral proteins CGAS, IRF3 and MAVS, thereby preventing cytokine overproduction . Also involved in pyroptosis by mediating cleavage and activation of gasdermin-E (GSDME). Cleaves XRCC4 and phospholipid scramblase proteins XKR4, XKR8 and XKR9, leading to promote phosphatidylserine exposure on apoptotic cell surface.