The Melcher Laboratory studies the structure and function of proteins that have central roles in cellular signaling. To do so, we employ X-ray crystallography in combination with biochemical and cellular methods to identify structural mechanisms of signaling at high resolution. In addition to their fundamental physiological roles, most signaling proteins are also important targets of therapeutic drugs. Determination of the three-dimensional structures of protein-drug complexes at atomic resolution allows a detailed understanding of how a drug binds its target and modifies its activity. This knowledge allows the rational design of new and better drugs against diseases such as diabetes, cancer, and neurological disorders. Three areas of focus in the lab are the cellular energy sensor AMPK, the receptors and key signaling proteins for the plant abiotic stress hormone abscisic acid (ABA), and the cancer target folate receptor.