The H+/K(+)-ATPase of gastric parietal cells catalyzes acid secretion in the stomach. Regulation of this pump's function involves its targeting to an intracellular storage compartment, which fuses with the apical plasma membrane in response to secretagogue stimulation. The H+/K(+)-ATPase must also be returned to this intracellular storage compartment to inactivate acid secretion. Recent research suggests that a number of targeting signals and protein-protein interactions participate in governing this process.