Faulty cellular signaling underlies the majority of inherited and acquired human diseases. To design a successful therapeutic intervention that has a chance of bringing the signaling back into balance, we need to understand fine molecular mechanisms involved. Every signaling pathway in the cell is mediated by protein interactions with other proteins and small regulatory molecules, such as hormones, neurotransmitters, second messengers, metabolites, ions, etc. Comprehensive understanding of these interactions requires elucidation of the structures of signaling proteins and small molecules targeting them. Therefore, structural biology is an integral part of the research in the Department of Pharmacology. Faculty members performing these studies use all cutting-edge tools available, including X-ray crystallography, electronic paramagnetic resonance, nuclear magnetic resonance, fluorescent labeling, targeted design of small molecules and signaling-biased proteins with therapeutic potential, as well as molecular modeling that complements these experimental approaches.