Each subunit comprises an extracellular N-terminal domain which comprises the orthosteric ligand-binding site; a transmembrane domain consisting of four interconnected alpha helices (M1-M4), with the extracellular M2-M3 loop involved in the gating mechanism; a large cytoplasmic domain between M3 and M4 involved in receptor trafficking and regulation; and a short extracellular C-terminus (Fig.1).
Each subunit comprises an extracellular N-terminal domain which comprises the orthosteric ligand-binding site; a transmembrane domain consisting of four interconnected alpha helices (M1-M4), with the extracellular M2-M3 loop involved in the gating mechanism; a large cytoplasmic domain between M3 and M4 involved in receptor trafficking and regulation; and a short extracellular C-terminus (Fig.1).