NMDA receptors are composed of four subunits that form a functional channel. Each subunit has a large extracellular N-terminal domain, a transmembrane domain with three membrane-spanning helices, and a reentrant pore loop. The intracellular C-terminal domain varies in length and is involved in intracellular signaling and receptor trafficking. The combination of different subunits influences the receptor's pharmacological properties and ion permeability.
