Light can be a powerful tool for manipulating molecular events. It is noninvasive, relatively straightforward to use, and can provide excellent spatial and temporal control. A light activation tool has been developed at the University of Geneva that can control both the activity and localization of various types of molecules in vivo. The tool could enable researchers to control a molecule at a specific location in a living organism without affecting the surrounding cells. It could be used for both research and medical treatments such as those for skin cancer. The researchers initially set out to modify a well-characterized inhibitor of Polo-like kinase 1 (Plk1). Their aim was to develop a way to control the activation and inactivation of a protein at a specific location within the organism, to better understand its functions. “Everything started from this methodological question,” professor Monica Gotta said. “We were looking for a way to inhibit a protein involved in cell division,...