Final answer:
Some IAPs target caspases for destruction by proteasomes. This process happens when the cell is unable to repair damage and leads to apoptosis.
Step-by-step explanation:
Some IAPs also target caspases, tagging them for destruction by proteasomes. Caspases are proteolytic enzymes that digest cellular proteins. If not, proteasomes target the Chk2-cyclin complex for degradation. Likewise, any P53 remaining bound to unphosphorylated Mdm2 is also targeted for proteasome destruction. The result is that any cell unable to correct effects of stress or chemical damage, or to repair DNA damage, is target for apoptosis.