Regulation of receptor function by cholesterol

Cholesterol influences many of the biophysical properties of membranes and is nonrandomly distributed between cellular organelles, subdomains of membr anes, and leaflets of the membrane bilayer. In combination with the high dy namics of cholesterol distribution, this offers many possibilities for regu lation of membrane-embedded receptors. Depending on the receptor, cholester ol can have a strong influence on the affinity state, on the binding capaci ty, and on signal transduction. Most important, cholesterol may stabilize r eceptors in defined conformations related to their biological functions. Th is may occur by direct molecular interaction between cholesterol and recept ors. In this review, we-discuss the functional dependence of the nicotinic acetylcholine receptor as well as different G protein-coupled receptors on the presence of cholesterol.