Apoptosis plays a major role in normal organism development, tissue homeostasis, and removal of damaged cells. Disruption of this process has been implicated in a variety of diseases such as cancer. The Bcl-2 family of proteins is comprised of critical regulators of apoptosis that can be divided into two classes: those that inhibit apoptosis and those that promote cell death. Bid, a pro-apoptotic Bcl-2 family member, is cleaved by caspase-8 in response to apoptotic signals, exposing the Bcl-2 homology 3 (BH3) domain which is normally buried in the full-length protein. The cleaved complex is myris-toylated and translocated to the mitochondrial membrane where it may induce mitochondrial Bax and Bak to oligomerize.
