Optogenetics, the approach to use light to control key processes, has revolutionized how researchers investigate cellular signaling pathways, cellular behavior and the function of large and interconnected tissues such as the brain. This highly successful combination of optics and genetics is powered by light-sensitive proteins, many of which have been engineered to bind to each other upon light stimulation. New research by scientists at the Institute of Science and Technology Austria (IST Austria) expands this optogenetic protein toolbox. In the study by the group of Harald Janovjak, driven by first author and PhD student Stephanie Kainrath, and colleagues at the Children’s Cancer Research Institute in Vienna, published today in Angewandte Chemie, the authors demonstrate the release of binding when exposed to green light.