Abstract

Genetic and biochemical studies yield information about the component proteins and interactions involved in a cellular signaling pathway. However this parts inventory often does not immediately reveal the in vivo signal processing capabilities and function of the pathway. Signaling pathways are complex systems with dynamic behavior and a systems level approach is needed to understand the physiological roles they play within the cell. We recently used such an approach to measure the signal processing behavior of the budding yeast HOG MAP kinase pathway in response to precisely varied temporal stimuli controlled with a microfluidic device. Despite being a well-studied pathway with well-known components the signaling dynamics and biochemical parameters of this pathway were not known. Our approach allowed us to characterize the pathway's in vivo signal processing and put bounds on all of the in vivo reaction rates. The experimental and theoretical techniques used in our study are general and can be applied to understanding other signaling pathways in a range of biological systems.