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. 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 (By similarity). Tetramers may be formed by the dimerization of dimers (By similarity). Found in a complex with GRIA2, GRIA3, GRIA4, CNIH2, CNIH3, CACNG2, CACNG3, CACNG4, CACNG5, CACNG7 and CACNG8 (By similarity). Interacts with HIP1 and RASGRF2. Interacts with SYNDIG1 and GRIA2 (By similarity). Interacts with DLG1 (via C-terminus). Interacts with LRFN1. Interacts with PRKG2. Interacts with CNIH2 and CACNG2. Interacts with CACNG5. Interacts (via C-terminus) with PDLIM4 (via LIM domain); this interaction as well as the interaction of PDLIM4 with alpha-actinin is required for their colocalization in early endosomes (By similarity). Interacts with SNX27 (via PDZ domain); the interaction is required for recycling to the plasma membrane when endocytosed and prevent degradation in lysosomes. Interacts (via PDZ-binding motif) with SHANK3 (via PDZ domain) (By similarity). Interacts with CACNG3; associates GRIA1 with the adapter protein complex 4 (AP-4) to target GRIA1 to the somatodendritic compartment of neurons (By similarity). Interaction with CACNG2, CNIH2 and CNIH3 promotes cell surface expression. Colocalizes with PDLIM4 in early endosomes. Displays a somatodendritic localization and is excluded from axons in neurons (By similarity). Localized to cone photoreceptor pedicles (By similarity). The M4 transmembrane segment mediates tetramerization and is required for cell surface expression. Palmitoylated. Depalmitoylated upon glutamate stimulation. Cys-603 palmitoylation leads to Golgi retention and decreased cell surface expression. In contrast, Cys-829 palmitoylation does not affect cell surface expression but regulates stimulation-dependent endocytosis (By similarity). Phosphorylated at Ser-645. Phosphorylated at Ser-710 by PKC. Phosphorylated at Ser-849 by PKC, PKA and CAMK2. Phosphorylated at Ser-863 by PKC, PKA and PRKG2 (By similarity). Phosphorylation of Ser-863 is reduced by induction of long-term depression and increased by induction of long-term potentiation (By similarity). 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. GRIA1 subfamily.