Theory of Two-Stage Chemoreception

Abstract

The central theme of the previous two chapters was the diffusion of proteins in the cell membrane. In this chapter we are going to use some of that work to study two-stage chemoreception, which is related to the ability of most cells to bind certain ligands nonspecifically, i.e. many ligands can bind weakly to the nonreceptor portion of the cell surface as well as specifically to appropriate receptors. Consequently, ligands may bind nonspecifically and then diffuse in the plane of the membrane until they encounter a receptor molecule. Such binding paths are often referred to as non-specific. These paths will be in competition with specific paths that involve binding directly from solution; in general both types of paths will contribute to the rate with which the cell captures ligands. In this short chapter we develop the theory of two-stage chemoreception for the standard model of chapter IV, following some work by Wiegel and DeLisi [1].