Shapeshifting receptors may explain mysterious drug failures

For sugar to taste sweet and for coffee to be stimulating, or even for light to be seen, first they all need to land on a G protein-coupled receptor. Ubiquitous and diverse, these receptors are a cell's chemical detection system: they sense substances in the surroundings and initiate intracellular pathways that underlie virtually all physiological processes—from taste and vision to hormonal regulation and neuronal communication. Nearly a third of all therapeutic drugs act by binding to these cell-surface receptors.