Functional consequences of lipid packing stress

When two monolayers of a non-lamellar lipid are brought together to form a planar bilayer membrane, the resulting structure is under elastic stress. T his stress changes the membrane's physical properties and manifests itself in at least two biologically relevant functional aspects. First, by modifyi ng the energetics of hydrophobic inclusions, it influences protein-lipid in teractions. The immediate consequences are seen in several effects that inc lude changes in conformational equilibrium between different functional for ms of integral proteins and peptides, membrane-induced interactions between proteins, and partitioning of proteins between different membranes and bet ween the bulk and the membrane. Secondly, by changing the energetics of spo ntaneous formation of non-lamellar local structures, lipid packing stress i nfluences membrane stability and fusion. (C) Published by 2000 Elsevier Sci ence Ltd.