The caspase3 network and its input-output characteristics and transition probability diagrams. (a) The caspase3 communication channel. The channel input molecules are EGF, insulin and TNF, and the channel output molecule is caspase3. The molecule ComplexI within the channel includes TNFR and TRADD-RIP-TRAF2 , whereas the molecule ComplexII stands for TRADD-RIP-TRAF2 and FADD . (b) The input–output relationships for the caspase3 normal channel. (c) Transition probability diagram for the normal caspase3 channel. Numbers above the arrows are transition probabilities. (d) Transition probability diagram for the pathological caspase3 channel where all the molecules in the channel are equally likely to be dysfunctional. Numbers above the arrows are transition probabilities.