Apoptosis can have elements of murder, as well as suicide.
Certain cells produce a 'death warrant' - a protein that binds to a specific receptor spanning the surface membrane of other cells. The portion of the death receptor that dangles inside the cell then attracts inactive caspases and converts them to an active form. Intriguingly, Strasser has shown that this particular highway to cell death bypasses Bcl-2. Thus, once the caspases have begun the cell's execution, Bcl-2 can no longer provide a reprieve. Tracing the different pathways to cell death and identifying the various check-points are important goals of the Division.