Dieter Oesterhelt, whose discovery of the first bacteriorhodopsin helped launch a new field of medical research, has passed away at the age of 82. In 1971, Oesterhelt and colleagues were investigating the properties of membranes that surround a microbe now known as the archaeon Halobacterium salinurum, which flourishes in high salt environments. Oesterhelt uncovered an archaeal protein that pumps protons out of cells when illuminated. This protein, which Oesterhelt named bacteriorhodopsin, functions as a light sensor, or photoreceptor. Oesterhelt’s discovery spurred the development of optogenetics, which uses light-triggered systems that can be deployed in live, free-moving animals to decipher the role of specific classes of—and even individual—neurons within labyrinthine brain circuits. Hundreds of laboratories around the world are now using this approach to untangle the elaborate networks that underlie healthy physiology and neurological disease. Oesterhelt’s discovery was recognized by a 2021 Lasker Basic Medical Research Award.

Listen to Dieter Oesterhelt discuss his work