Voltage-Gated Proton Channels Find Their Dream Job Managing the Respiratory Burst in Phagocytes

The proton channel molecule shares many similarities with the VSD of other voltage-gated channels. Unlike most channels, the proton channel is a dimer with twin conduction pathways. Although steeply voltage dependent, the gating of proton channels depends strongly on the pH gradient, with the result that it almost invariably extrudes acid when it opens. Proton channels are uniquely suited to their job in phagocytes, where they optimize NADPH oxidase activity by simultaneously compensating charge, minimizing pH changes both in cytoplasm and phagosome, minimizing osmotic imbalance, and providing substrate protons for ROS production in the phagosome.