Purification of Lipid Rafts from Cultured Cells

Lipid-rich lipid rafts are microdomains of the plasma membrane that are resistant to low concentrations of nonionic detergent. This forms the basis for their isolation. Either a microsomal fraction or a postnuclear supernatant are loaded beneath a discontinuous iodixanol gradient. If all the solutions contain 0.5–1.0% Triton X-100, the intact lipid rafts float to the top of the gradient while all of the other detergent-solubilized membranes remain at the bottom.