 G protein-coupled receptor

A G protein-coupled receptor is a cell-surface receptor that relays activation through a G protein on the intracellular side of the cell membrane. The activated G protein can regulate an enzyme or ion channel, so a GPCR supplies a concrete metabotropic receptor example: ligand recognition and the eventual response are connected through distinct components. Different G proteins couple to different targets. See Alberts et al., Molecular Biology of the Cell, 4th edition: signaling through G-protein-linked cell-surface receptors.

G protein-coupled receptors (GPCRs) are a large family of membrane proteins that play a critical role in cellular signaling. These receptors are characterized by their ability to pass through the cell membrane seven times (hence they are also known as seven-transmembrane receptors). GPCRs respond to a variety of external signals, including hormones, neurotransmitters, and environmental stimuli, and are involved in many physiological processes.