Abstract
Phototaxis in Archaea employs an integral membrane complex composed of a photoreceptor that is similar to the light-driven proton pump bacteriorhodopsin, and a transducer protein that is similar to the familiar eubacterial chemotaxis receptors. Recent structural studies have revealed how these proteins are assembled in the membrane, and provide a heuristic framework for future work on the mechanism of signal transduction by this important class of molecules.