A One-Domain Voltage-Gated Sodium Channel in Bacteria

Learning, memory, movement, sensation, and other complex processes are all coordinated by electrical signals (action potentials) conducted along the long fibers of nerve cells. In both multicellular animals and complex single-cell organisms such as the eukaryote Paramecium, electrical signals are generated locally and action potentials are conducted globally through the activity of a family of voltage-gated sodium channels. This ion channel family was not thought to exist in bacteria, the jellyfish being the simplest organism in which it had been found (1). On page 2372 of this issue, Ren et al. (2) surprise us with their discovery of the first voltage-gated ion channel in a prokaryote. They describe the structure and function of a sodium channel in the salt-loving bacterium Bacillus halodurans.