ABSTRACT
Biological membranes hold cells together and divide them into compartments. They are also home to the lipid-soluble proteins that comprise roughly one-third of the genome and perform a variety of functions, including energy production and storage, signal transduction, and the formation of channels for the transport of substances into and out of cells and between their compartments. In 1972, Singer and Nicolson [1] assimilated available data into a model for the molecular organization of biological membranes that is now taken for granted. According to this ‘‘fluid mosaic’’ model, a lipid bilayer forms the membrane matrix in which proteins are embedded. This matrix is fluid at physiological temperatures, and both lipids and proteins are free to diffuse in the plane of the membrane.
