Caspase-9 cleavage, do you need it?
Caspase-9, which is activated by association with the Apaf-1 (apoptotic protease-activating factor-1) apoptosome complex, cleaves and activates the downstream effector caspases-3 and -7, thereby executing the caspase-cascade and cell-death programme. Although caspase-9 does not need to be cleaved to be active, apoptotic cell death is always accompanied by autocatalytic cleavage and by further downstream effector caspase-dependent cleavage of caspase-9. In this issue of the Biochemical Journal, Denault and co-workers evaluate the role of caspase-3-dependent cleavage of caspase-9 and conclude that this mechanism mainly serves to enhance apoptosis by alleviating XIAP (X-linked inhibitor of apoptosis) inhibition of the apical caspase.
Twiddy
Davina
D
MRC Toxicology Unit, Hodgkin Building, University of Leicester, Lancaster Rd, Leicester LE1 9HN, UK.
Cain
Kelvin
K
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism
D004791:Enzyme Inhibitors; D051636:X-Linked Inhibitor of Apoptosis Protein; D053148:Caspase 3; D053179:Caspase 7; D053453:Caspase 9