Logic models of pathway biology.

Living systems seamlessly perform complex information processing and control tasks using combinatorially complex sets of biochemical reactions. Drugs that therapeutically modulate the biological processes of disease are developed using single protein target strategies, often with limited knowledge of the complex underlying role of the targets. Approaches that attempt to consider the combinatorial complexity from the outset might help identify any causal relationships that could lead to undesirable or adverse side effects earlier in the development pipeline. Such approaches, in particular logic methodologies, might also aid pathway selection and multiple target strategies during the drug discovery phase. Here, we describe the use of logic as a tractable and informative approach to modelling biological pathways that can allow us to improve our understanding of the dependencies in complex biological processes.