Cholesterol interaction with proteins

Cholesterol interacts with proteins and influences their function. 

Epand RM, Thomas A, Brasseur R, Epand RF. Cholesterol interaction with proteins that partition into membrane domains an overview. Subcell Biochem. 2010 51 253-278. 

Although some membrane proteins are known to interact with cholesterol, cholesterol interactions with other lipids have been studied much more thoroughly. Most notably, cholesterol interacts strongly with sphingomyelin, perhaps by forming complexes, which results in a liquid-liquid phase separation of cholesterol-rich and cholesterol-poor phases (13). The cholesterol-rich phases exhibit more chain order and therefore are referred to as liquid-ordered (lo) phases, whereas the cholesterol-poor phases are called liquid-disordered (Id) phases. 

Fantini J, Barrantes FJ. How cholesterol interacts with membrane proteins an exploration of cholesterol-binding sites including CRAG, CARC, and tilted domains. Front Physiol. 2013 4 31. 

When most lipids circulate in the body, they do so in the form of lipoprotein complexes. Simple, unesterified fatty acids are merely bound to serum albumin and other proteins in blood plasma, but phospholipids, triacylglycerols, cholesterol, and cholesterol esters are all transported in the form of lipoproteins. At various sites in the body, lipoproteins interact with specific receptors and enzymes that transfer or modify their lipid cargoes. It is now customary to classify lipoproteins according to their densities (Table 25.1). The densities are... 

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