Receptors which transduce extracellular signals across the cell membrane. At the external side they receive a ligand (a photon in case of opsins), and at the cytosolic side they activate a guanine nucleotide-binding (G) protein. These receptors are hydrophobic proteins that cross the membrane seven times.

› Molecular function

› G-protein coupled receptor activity [ GO:0004930 ]
› G-protein coupled receptor signaling pathway [ GO:0007186 ]