Protection of the membrane permeability barrier by annexins.

Biological membranes are exposed to a number of chemical and physical stresses that may alter the structure of the lipid bilayer in such a way that the permeability barrier to hydrophilic molecules and ions is degraded. These stresses include amphiphilic molecules involved in metabolism and signaling, highly charged polyamines, membrane-permeating peptides, and mechanical and osmotic stresses. As annexins are known to bind to lipid headgroups in the presence of calcium and increase the order of the bilayer lipids, this study addressed whether this activity of annexins provides a potential benefit to the membrane by protecting the bilayer against disruptions of this nature or can promote restoration of the permeability barrier after damage by such agents.