Ionotropic glutamate receptor. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inactive state, characterized by the presence of bound agonist. May be involved in the transmission of light information from the retina to the hypothalamus (By similarity). Homotetramer or heterotetramer of pore-forming glutamate receptor subunits. Tetramers may be formed by the dimerization of dimers (Probable). The unedited version (Q) assembles into a functional kainate-gated homomeric channel, whereas the edited version (R) is unable to produce channel activity when expressed alone. Both edited and unedited versions can form functional channels with GRIK4 and GRIK5. Interacts with KLHL17 (By similarity). At least 2 isoforms are produced. Most abundant in the cerebellum. Also present in the suprachiasmatic nuclei of the hypothalamus. Partially edited. The postsynaptic actions of Glu are mediated by a variety of receptors that are named according to their selective agonists. This receptor binds domoate > kainate > L-glutamate = quisqualate > CNQX = DNQX > AMPA > dihydrokainate > NMDA (By similarity). Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. GRIK1 subfamily.