Receptor for glutamate that functions as ligand-gated ion channel in the central nervous system and plays an important role in excitatory synaptic transmission. 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. In the presence of CACNG4 or CACNG7 or CACNG8, shows resensitization which is characterized by a delayed accumulation of current flux upon continued application of glutamate (By similarity). Homotetramer or heterotetramer of pore-forming glutamate receptor subunits. Tetramers may be formed by the dimerization of dimers. Interacts with EPB41L1 via its C-terminus. Isoform 3 interacts with PRKCABP. Found in a complex with GRIA1, GRIA2, GRIA3, CNIH2, CNIH3, CACNG2, CACNG3, CACNG4, CACNG5, CACNG7 and CACNG8. Interacts with CACNG5 and PRKCG. Interaction with CNIH2, CNIH3 and PRKCG promotes cell surface expression. Detected in cerebellum (at protein level). The M4 transmembrane segment mediates tetramerization and is required for cell surface expression. Palmitoylated. Depalmitoylated upon glutamate stimulation. Cys-611 palmitoylation leads to Golgi retention and decreased cell surface expression. In contrast, Cys-837 palmitoylation does not affect cell surface expression but regulates stimulation-dependent endocytosis (By similarity). Phosphorylated at Ser-862 by PRKCG; phosphorylation increases plasma membrane-associated GRI4 expression. The postsynaptic actions of Glu are mediated by a variety of receptors that are named according to their selective agonists. This receptor binds AMPA (quisqualate) > glutamate > kainate. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. GRIA4 subfamily.