Glutamate receptor, ionotropic, delta 2, also known as GluD2, GluRδ2, or δ2, is a protein that in humans is encoded by the GRID2gene.[5][6] This protein together with GluD1 belongs to the delta receptor subtype of ionotropic glutamate receptors. They possess 14–24% sequencehomology with AMPA, kainate, and NMDA subunits, but, despite their name, have been found not to directly promote neuronal activation in response to glutamate or various other glutamate agonists.[7]
delta iGluRs have long been considered orphan receptors as their endogenousligand was unknown. They are now believed to bind glycine and D-serine but these do not result in channel opening.[8][9]