The Fluid-Mosaic Nature of the Thylakoid Membrane

In 1972 Singer and Nicolson (1) proposed that biological membranes are fluid-mosaic structures. Their model implied that the lipid bilayer acted as a two-dimensional fluid in which protein complexes and other hydrophobic components could freely diffuse, both rotationally and laterally. Evidence for such motions are numerous (2). Despite this it is also quite obvious that not all proteins in membranes are freely diffusing. Indeed the clustering of proteins to specific regions is necessary to form well known features, such as gap junctions, coated pits etc.