Dual mechanism for the action of cholesterol on membrane permeability

CHOLESTEROL, which is a widespread component of the plasma membrane, has a substantial influence on the permeability properties of lipid bilayer1–3 and cell membranes4. Although the effects of cholesterol on membrane structure are increasingly well understood5 the mechanisms by which cholesterol modulates membrane permeability are obscure, mainly because it is difficult to deduce permeability properties from the knowledge of membrane structure alone.