Systems Analysis of Regulatory Processes Underlying Eukaryotic Gradient Perception

This paper analyzes regulatory processes involved in the biological process of directed cell locomotion - known as chemotaxis. We focus on the nature of regulation involved in a subprocess of chemotaxis called gradient perception. We examine two different models from a dynamics/control perspective to gain insight into the working mechanisms of these models. One model is a minimal model which reconciles gradient perception to the property of adaptation. The second model is a biochemical model of a lipid network and its regulation by enzymes. In both cases, we focus on the extent of regulation of the modules/networks by inputs, and examine various limiting cases. Both the models and the resulting insights have broader applicability than the context in which they were developed.