G-protein-linked receptor

G-protein-linked receptor [¦jē ‚prō‚tēn ‚liŋkt ri′sep·tər]

(cell and molecular biology)

A cell surface receptor that consists of a polypeptide chain threaded across the membrane seven times and that, when activated by the binding of a ligand, in turn activates a cytosolic G-protein molecule, which then initiates a cascade of reactions effecting the intracellular response to the extracellular signal (the ligand).