The present invention provides a method of identifying an effective agent that alters the association of a Bit1 polypeptide with an AES polypeptide. The method is practiced by contacting a Bit1 polypeptide, or active fragment thereof, and an AES polypeptide, or active fragment thereof, with an agent under conditions that allow the Bit1 polypeptide or active fragment thereof to associate with the AES polypeptide or active fragment thereof; and detecting an altered association of the Bit1 polypeptide or active fragment thereof and the AES polypeptide or active fragment thereof, where an altered association indicates that the agent is an effective agent that alters the association of a Bit1 polypeptide with an AES polypeptide. Such an effective agent can modulate apoptosis and can be a useful therapeutic agent.