ligand-binding domain of membrane-bound glutamate receptors that mediate excitatory transmission on the cellular surface through initial binding of glutamate; categorized into ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs)
Ligand-binding domain of membrane-bound glutamate receptors that mediate excitatory transmission on the cellular surface through initial binding of glutamate and are categorized into ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs). The metabotropic glutamate receptors (mGluR) are key receptors in the modulation of excitatory synaptic transmission in the central nervous system. The mGluRs are coupled to G proteins and are thus distinct from the iGluRs which internally contain ligand-gated ion channels. The mGluR structure is divided into three regions: the extracellular region, the seven-spanning transmembrane region and the cytoplasmic region. The extracellular region is further divided into the ligand-binding domain (LBD) and the cysteine-rich domain. The LBD has sequence similarity to the LIVBP, which is a bacterial periplasmic protein (PBP), as well as to the extracellular region of both iGluR and the gamma-aminobutyric acid (GABA)b receptor. iGluRs are divided into three main subtypes based on pharmacological profile: NMDA, AMPA, and kainate receptors. All family C GPCRs have a large extracellular N terminus that contain a domain with homology to bacterial periplasmic amino acid-binding proteins.
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