Quite a few components have been identified in the apoptotic signalling cascades, and most of them have been touched on here today: Bcl-2 family proteins, mitochondria, cytochrome C and caspases, but we also have protein kinases, which seem to play quite an important role, although we don't know too much about what these phosphorelations really mean or what they are doing. Of course, where there are kinases there are normally also phosphotases, and there we know even less.