Receptor for glutamate. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. The postsynaptic actions of Glu are mediated by a variety of receptors that are named according to their selective agonists. Promotes synaptogenesis and mediates the D-Serine-dependent long term depression signals and AMPA receptor endocytosis of cerebellar parallel fiber-Purkinje cell (PF-PC) synapses through the beta-NRX1-CBLN1-GRID2 triad complex. Tetramer; dimer of dimers (By similarity). Interacts with EML2, MAGI2 (via PDZ domains) and AP4M1 (By similarity). Interacts with BECN1, GOPC, GRID2IP, SHANK1 and SHANK2 (PubMed:12372286, PubMed:15207857, PubMed:17027646). Interacts with CBLN2, but not with CBLN4 (PubMed:22220752). Interacts with CBLN1 (via C1q domain); the interaction is CBLN1-NRX1 complex formation-dependent; CBLN1-binding is calcium-independent; CBLN1 hexamers anchor GRID2 N-terminal domain dimers to monomeric NRXN1 isoform beta; promotes synaptogenesis and mediates the D-Serine-dependent long term depression signals and AMPA receptor endocytosis (PubMed:20395510, PubMed:21410790, PubMed:22220752, PubMed:29782851). Expressed selectively in cerebellar Purkinje cells where it is localized in dendritic spines. The PDZ-binding motif mediates interaction with GOPC. Defects in Grid2 are the cause of the Lurcher phenotype. Heterozygous animals display a characteristic swaying of the hind quarters and jerky up and down movements following cerebellar Purkinje cell degeneration during postnatal development. Homozygous animals die shortly after birth because of a massive loss of midbrain and hindbrain neurons during late embryogenesis. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. GRID2 subfamily.