Glutamate receptor subunit 5 (also known as Glutamate receptor ionotropic, kainate 2) (GluR5 (current nomenclature: GRIK2))

Glutamate receptor subunit 5 (GluR5, now formally GRIK2) is a protein subunit that assembles with others to form kainate-type ionotropic glutamate receptors. These receptors are ligand-gated cation channels primarily located in the central nervous system, where they mediate fast excitatory neurotransmission via binding to glutamate, the principal excitatory neurotransmitter in the brain. GluR5-containing receptors play essential roles in synaptic plasticity and modulation of neurotransmitter release, and have been implicated in diverse physiological processes as well as diseases such as epilepsy, neurodegeneration, and psychiatric disorders. Structurally, GluR5 shares a common architecture with other iGluRs, forming tetramers with a central ion channel pore; binding of agonists or antagonists to the extracellular ligand-binding domain induces conformational changes that regulate channel gating and neuronal excitability[1][3][7][5]. Selective antagonists, such as UBP302 and UBP310, provide tools to dissect specific functional roles of GluR5-containing receptors and offer potential for targeted therapeutics, though adverse CNS effects present a major challenge[1].

Other names

GRIK2 (current gene symbol)Glutamate receptor, ionotropic, kainate 2KA2GRIK5 (historically imprecise but sometimes used in literature; correct: GRIK2)

Modulation of neuronal excitability through gated cation (Na+, K+, to lesser degree Ca2+) flux - Drugs may act as competitive antagonists (e.g., UBP302, UBP310) or non-competitive antagonists, inhibiting synaptic transmission through channel block or allosteric effects[1] - Agonists (such as kainic acid) promote receptor activation and excitatory signaling