(Organized by Donald W. Hilgemann, Scott D. Emr, and Pietro de Camilli)
By virtue of the strength of hydrophobic interactions and the malleability of phospholipid acyl chains, membrane lipids become one of the important glues of life. The liquid-crystalline organization of the bilayer component of biological membranes enables the membranes to be effective, cohesive, and yet flexible, barriers separating two fluid compartments. Integral membrane proteins are imbedded into the bilayer, where they catalyze the selective transfer of information and material between the two compartments. Hydrophobic interactions between the proteins' bilayer-spanning domains and the bilayer lipids cause the lipids to pack tightly around the proteins, thereby maintaining the barrier properties. Because the bilayer lipids are organized as a liquid-crystalline sheet, the flexible lipids will accommodate protein conformational changes that involve the protein/bilayer boundary. Individual lipid molecules also may be imbedded at protein–protein interfaces where they not...
