|MoBio||G-protein-Coupled Receptors||Chapter 2|
The major role of G-protein-coupled receptors is to transmit signals into the cell (Chapter 6 Section D). They are characterized by seven transmembrane segments. This class of membrane proteins can respond to a wide range of agonists, including photon, amines, hormones, neurotransmitters and proteins. Some agonists bind to the extracellular loops of the receptor, others may penetrate into the transmembrane region.