Research Progress of the Inhibitor-of-protein XIAP

XIAP is a mammalian inhibitor of apoptosis protein, which belongs to the inhibitor-of-apoptosis protein(IAP)family. XIAP is a potent suppressor of apoptotic cell death. The BIR domain of XIAP binds directly to certain initiator and effector caspases,thus blocks the mitochondria death pathway. XIAP also can be as a acti-tor of NF -κB pathway and inhibit caspase - 8. This differs the effects of Bel - 2 - related apoptotic suppressors, which function at points that are distal in the death pathway, upstearm of the apoptosome, to prevent integration of the caspase-activating signal. Smac is a mitochondria protein that is released along with cytochrome c during apoptosis abd protome cytochrome-dependent caspase activation by neutralizing XIAP. The RING finger domain of XIAP has the activity of ubiquititin protein ligase E3 and can cause the auto - ubiquitination and degradaton of XIAP,and regulate the activation of XIAP.