Ghrelin receptor conformational dynamics regulate the transition from a preassembled to an active receptor:Gq complex

Significance G protein-coupled receptors (GPCRs), one of the largest cell surface receptor families, transmit their signals through the coupling of intracellular partners, such as the G proteins. Knowing how this coupling occurs is essential, because it governs the entire signaling process. To address this open question, we used a purified GPCR as a model to which we applied various state-of-the-art biochemical and biophysical approaches. By doing so, we provide direct experimental evidence of a signaling mechanism in which receptor conformational changes are directly linked to a rearrangement of a preassembled complex between the receptor and its cognate Gq protein. This sheds light on the way in which a GPCR interacts with G proteins to trigger signaling.