Conditional Localization Pharmacology Manipulates the Cell Cycle with Spatiotemporal Precision

Traditional pharmacology has limited control of drug activity and localization in space and time. Herein, we describe an approach for kinase regulation using conditional localization pharmacology (CLP), where an inactive caged inhibitor is localized to a site of interest in a dormant state using intracellular protein tethering. The activity of the inhibitor can be regulated with spatial and temporal precision in a live cellular environment using light. As a proof of concept, a photocaged MPS1 kinase inhibitor (reversine) bearing a HaloTag ligand tether was designed to manipulate the cell cycle. We demonstrate that this new caged reversine halo probe (CRH) strategy is capable of efficient localization and exceptional spatiotemporal control over spindle assembly checkpoint (SAC) silencing and mitotic exit.