Xiaokun Shu is interested in redefining how we read, map, and rewrite signaling networks in living systems by developing new classes of biosensors and tools based on first physical and chemical principles. Our innovations enable quantitative visualization, probing, and manipulating the spatiotemporal dynamics of signaling networks in cells and animals, including kinase activation, protease activity, and protein-protein interactions, which regulate virtually all major signaling pathways that underlie cell behavior, animal development, and disease.