Single-molecule kinetic analysis of stochastic signal transduction mediated by G-protein coupled chemoattractant receptors

Abstract

Cellular chemotactic behaviors are typical examples of stochastic signal transduction in living cells that have been investigated in detail both experimentally and theoretically. In this chapter, we describe single-molecule kinetic analysis for stochastic signal transduction in chemotactic responses mediated by G protein-coupled chemoattractant receptors in order to give deeper understanding of the stochastic nature in chemotactic signaling processes. We also describe theoretical analysis of receptor-mediated chemotactic signaling, which reveals that noise generated in the transmembrane signaling by G protein-coupled chemoattractant receptors limits the precision of the gradient sensing. This suggests that receptor-G protein coupling and its modulation have an important role for improving the signal-to-noise ratio of chemotactic signals and thus cellular chemotaxis. Extending this beyond G protein signaling, combining single-molecule kinetic analysis with theoretical analysis offers a new tool in exploring the relationship between the kinetic properties of signaling molecules and their corresponding cellular responses in general. © Springer Science+Business Media B.V. 2011.