Close Encounters of the Oily Kind: Regulation of Transporters by Lipids

The dynamic lipid bilayer and membrane phases. Three different phases are generally described for membrane lipids. A) In the “solid gel state,” or “solid crystalline state,” hydrocarbon chains are typically found in the trans configuration and are highly ordered. Low temperatures can favor the solid gel phase. B) This “liquid crystalline state,” or “liquid disordered state,” is typical of high temperature and shows a disordered configuration of acyl chains. High lateral mobility is associated with the liquid disordered state; most pure fatty acid, detergent, or phospholipid liposomes are found in this state at room temperature. C) The “liquid ordered state” occurs in the presence of high levels of sphingolipids and cholesterol and results in mobility slightly under that of the pure liquid disorderd state. Detergent-resistant microdomains or lipid rafts are endogenous liquid-ordered membrane patches. See text for details. Adapted from (63).