Modular analysis of signal transduction networks

This paper introduces compelling problems of biological systems and signaling networks to show how engineering tools can be applied to the analysis of the cellular machinery. The mechanisms that cells have developed to process information are described, and the decomposition of signalling networks into subsystems is discussed. A novel criterion for defining modules based on the absence of retroactivity is also presented, and some simple criteria for the analysis of the resulting units are introduced. Two simple examples, two-component signaling and MAPK cascade, and a more complicated example, EGF signaling, were reviewed. An important point to discuss in model analysis for cellular system is the availability of experimental data that is sufficient to verify the model structure and model parameters.