Membrane Cholesterol — Is Enough Too Much?

Cholesterol is one of the most enigmatic molecules in human biology. On the one hand, it is an essential structural component of membranes and lipoproteins. On the other, it contributes to the pathogenesis of diseases as diverse as gallstones, atherosclerosis, and hemolytic anemia.Cholesterol's role in disease is related to its extremely low solubility in water. Fortunately, cholesterol is readily solubilized by detergent-like molecules, the most common of which are the phospholipids. Unlike cholesterol, phospholipids form lamellar membranous structures in an aqueous environment. Cholesterol is capable of interdigitating among the phospholipids within such structures. It is these lamellae of phospholipid . . .