May regulate AMPA receptor content at nascent synapses, and have a role in postsynaptic development and maturation. Homodimer. Interacts with GRIA1 and GRIA2 (By similarity). Shuttles between the cell surface and early endosome membrane. Enriched in the cerebellum and also expressed in the neocortex and modestly in the hippocampus (at protein level) (PubMed:26660156). Expressed in hippocampal neurons, both in cell body and neurites, however its presence is enriched at excitatory synapses and also found in postsynaptic cells (PubMed:20152115). Expressed during synaptogenesis with levels peaking during the second week of postnatal development (PubMed:20152115). Expression increases between postnatal days 7 and 14 and remains high at postnatal day 21 and at 2 months of age (PubMed:26660156). As development proceeds, an increasing percentage becomes localized to excitatory synapses (PubMed:20152115). Belongs to the CD225/Dispanin family.