Sensing voltage across lipid membranes

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Abstract
The ability of proteins to detect electrical potentials across biological membranes is critical for many cellular processes, including the generation and propagation of nerve impulses. Ground-breaking structural studies on the 'activated' conformation of voltage-sensing domains have revealed a surprisingly intimate interaction between these protein domains and the surrounding lipid bilayer. Mobile cationic residues within voltage-sensor domains are stabilized within the membrane by interactions with anionic residues and with the phosphate moiety of lipid end groups. Although the structure of the 'resting' conformation of the voltage sensor is anxiously awaited, the available data are consistent with half-bilayer dimension motions of charged residues through a focused electric field. For more background, visit the web focus on http://www.nature.com/nature/focus/voltagesensing/ The detection of electrical potentials across lipid bilayers by specialized membrane proteins is required for many fundamental cellular processes such as the generation and propagation of nerve impulses. These membrane proteins possess modular voltage-sensing domains, a notable example being the S1–S4 domains of voltage-activated ion channels. Ground-breaking structural studies on these domains explain how voltage sensors are designed and reveal important interactions with the surrounding lipid membrane. Although further structures are needed to understand the conformational changes that occur during voltage sensing, the available data help to frame several key concepts that are fundamental to the mechanism of voltage sensing.