IAPs function by binding to and inhibiting caspases, which are the protease enzymes that carry out apoptosis. By inhibiting these enzymes, IAPs prevent the cascade of events that lead to cell death. Some well-known IAPs include XIAP (X-linked inhibitor of apoptosis protein), cIAP1, and cIAP2. These proteins contain specific domains such as BIR (Baculovirus IAP Repeat) domains that enable them to bind to and inhibit caspases.