[G protein-coupled receptors in the spotlight].

G protein-coupled receptors (GPCR) are the largest family of integral membrane proteins found in the plasma membrane of mammalian cells. GPCR respond to a large variety of ligands such as amines, lipids, hormones and amino-acids, which are involved in inter-cellular signalling events in a multitude of physiological and pathological processes. GPCRs are therefore key regulators of signal transduction by which cells respond to variations in their environment. During the last five years, striking progress has been made to solve high-resolution structure of GPCR. The most recent successes are the structures of the β(1) and β(2) adrenoreceptors and the adenosine A(2A) receptor bound to a variety of agonists. Most importantly, the structure of the β(2) adrenoreceptor in complex with a trimeric G protein, Gs, was recently reported. This review will present an overview of the X-ray structure determination of the GPCR and of their activation mechanism.