Molecular tools for fast switching of cellular events. Investigations of single switches but also complex signaling events are often experimentally accessible by inducing an artificial switch on the molecular level inside intact cells. Based on the extensive experience of the Schultz in developing tools for switching molecular events and its detection, the Z01 project will provide already existing tools such as caged lipids and chemical dimerizer systems and will develop new tools in close collaboration for the TRR partners. The novel probes will be based on small molecules but also genetically encoded constructs and cover a large variety of applications from endosomal trafficking to fluorescent probes that sense double-stranded RNA. Z01 will give consortium partners access to unique experimentation possibilities.