2. Classification of cell-surface receptors Ion-channel-linked receptors Involved in rapid synaptic signaling between electrically excitable cells G-protein coupled receptors(GPCR Seven-pass transmembrane protein, indirectly regulate the activity of a target protein through a trimeric GTP-binding protein(G-protein) Enzyme-linked receptors Single-pass transmembrane protein function directly as enzyme or directly associated with enzymes they activate Others2. Classification of cell-surface receptors • Ion-channel-linked receptors – Involved in rapid synaptic signaling between electrically excitable cells • G-protein coupled receptors (GPCR) – Seven-pass transmembrane protein, – indirectly regulate the activity of a target protein through a trimeric GTP-binding protein (G-protein) • Enzyme-linked receptors – Single-pass transmembrane protein, – function directly as enzyme or directly associated with enzymes they activate • Others