G protein-coupled receptors (GPCRs) are membrane proteins that transduce a vast array of extracellular signals into intracellular reactions ranging from cell-cell communication processes to physiological responses. They play an important role in a variety of diseases from cancer and diabetes, to neurodegenerative, inflammatory and respiratory disorders. GPCRs are therefore of utmost interest in drug development: over half of all prescription drugs currently on the market act by targeting these...