Peter Hegemann

Peter Hegemann (born December 11, 1954, Münster, Germany) is a German biochemist and biophysicist whose work contributed to the development of optogenetics—a research method in which optics and genetics are combined in technologies designed to control well-defined events in cells of living animal tissue. For his discoveries, Hegemann was awarded the 2026 Nobel Prize for Physiology or Medicine, shared with American psychiatrist and bioengineer Karl Deisseroth and German biophysicist Georg Nagel.

In 1975 Hegemann began studies in chemistry at the University of Münster. He soon after moved to Ludwig Maximilian University in Munich, where he turned his attention to biochemistry, graduating with a degree in 1980. He subsequently pursued doctoral studies at the Max Planck Institute of Biochemistry in Martinsried, Germany, where he joined the laboratory of renowned biochemist Dieter Oesterhelt, who in 1971 discovered bacteriorhodopsin, the first pigmented protein found in certain bacteria that functions in the conversion of light energy into chemical energy. Hegemann’s research centered on halorhodopsin, a protein that uses light energy to pump chloride ions across the membrane in certain bacteria. After receiving a Ph.D. in 1984, Hegemann carried out postdoctoral studies in the physics department at Syracuse University in New York. In 1986 he became a researcher at the Max Planck Institute, where his work focused on photoreceptors in microalgae.

Hegemann initially became interested in mechanisms of light detection by the single-celled green alga Chlamydomonas while at Syracuse. When Chlamydomonas senses light, it moves toward it, to carry out photosynthesis, or away from it, to protect itself from damage induced by overly intense light. This sort of movement in response to light is known as phototaxis. At Max Planck, Hegemann set out to identify the light-sensitive proteins that drive this behavior. In 1993 he continued his research at the University of Regensburg. There, in the early 2000s, in collaboration with Nagel, he discovered and characterized a class of light-sensitive proteins known as channelrhodopsins, which in response to specific wavelengths of light permit ions to cross the algal membrane.

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Hegemann and Nagel’s discovery served as a crucial breakthrough for the establishment of optogenetics. They found that genes producing channelrhodopsins could be inserted into certain neurons, rendering the altered cells responsive to light. In this way, researchers can use light to turn cells on or off with remarkable precision and resolution in living, freely moving animals.

Hegemann later became a professor of experimental biophysics at Humboldt University of Berlin. In 2015 he was made Hertie Professor für Neurowissenschaften, an endowed title in Germany for researchers whose work aims to advance neuroscience.