The function of ENSG00000152208 (GRID2, glutamate ionotropic receptor delta type subunit 2) is as follows. Member of the ionotropic glutamate receptor family, which plays a crucial role in synaptic organization and signal transduction in the central nervous system (PubMed:34936451, PubMed:27418511, PubMed:40957579). Although it shares structural features with ionotropic glutamate receptors, does not bind glutamate as a primary ligand (PubMed:34936451). 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 NRX1B-CBLN1-GRID2 triad complex (PubMed:27418511). In the presence of neurexins and cerebellins, forms cation-selective channels that are proposed to be gated by glycine and D-serine (PubMed:34936451). Cation-selective ion channel activity can be triggered by GRM1 in Purkinje cells (PubMed:24357660, PubMed:27276689). {ECO:0000269|PubMed:24357660, ECO:0000269|PubMed:27276689, ECO:0000269|PubMed:27418511, ECO:0000269|PubMed:34936451, ECO:0000269|PubMed:40957579}.