Chapter 1 – Functional Roles of Lipids in Membranes

Biological membranes define the outer limits of cells and organelles and are composed of phospholipids, glycolipids, sphingolipids, sterols and proteins. Each lipid class is composed of numerous variants within their respective polar and apolar domains. The apolar and polar nature of these amphipathic lipids is the basis for forming biological membranes with which membrane proteins associate either as integral proteins that span the membrane bilayer or as peripheral proteins that associate with the membrane surface. Individual lipids, once thought mainly to provide cell barrier function and a solvent for membrane proteins, are now recognised as critical components that directly influence an array of cellular functions. Physical and chemical properties of lipids that determine the properties of biological membranes, genetic approaches used to alter cellular lipid composition and examples of how lipid–protein interactions define specific roles for lipids in cell function are discussed.