Disclosed is substantially pure DNA encoding mammalian IAP polypeptides;
substantially pure polypeptides; and methods of using such DNA to express the IAP
polypeptides in cells and animals to inhibit apoptosis. Also disclosed are conserved
regions characteristic of the IAP family and primers and probes for the identification
and isolation of additional IAP genes. In addition, methods for treating diseases
and disorders involving apoptosis are provided.