Chapter 8 Lateral Diffusion of Lipids and Proteins

Abstract

Publisher Summary The chapter discusses a study on lateral diffusion of lipids and proteins. Before a century, Overton began to examine one biologically essential function of the membrane, to serve as a barrier that allows selective transport across the membrane. In the 1970s, biologists began to examine another essential function of the membrane to allow diffusion and reaction within the plane of the membrane. This chapter presents a discussion on the factors that affect the lateral diffusion coefficient D , the effects of heterogeneity on lateral diffusion, and two tools developed in physics to characterize heterogeneous systems, percolation theory and anomalous diffusion. The heterogeneity of cell membranes is an active area of research, and many excellent reviews are available with viewpoints ranging from computational statistical mechanics to detailed biochemical studies of receptors. According to the fluid mosaic model, the membrane is a lipid bilayer, forming a two-dimensional oriented viscous solution of integral proteins in a fluid lipid matrix. The lateral diffusion of membrane components is essential to a variety of physiological processes in cells. The major qualitative modification required in the Singer–Nicolson model is to allow for heterogeneity. Percolation theory and anomalous diffusion are standard tools used in physics to characterize heterogeneity.