Light Microscopy Beyond the Wavelength Limit: Methods for Characterizing Cell Surface Membranes

The cell surface mediates the flow of information and metabolites between a cell and its environment. We are interested in understanding the lateral organization of the surface, as part of our program in understanding its function. The model of lateral organization of cell surface membranes is evolving from one which emphasizes mobility and autonomy of membrane constituent molecules, to another which emphasizes the lateral concentration of membrane proteins and lipids into patches and membrane microdomains.1 Indirect evidence suggests that diameters of these patches and microdomains are often <_ a wavelength of visible light, and so cannot be readily resolved by conventional light microscopy