G-protein coupled receptor for glutamate. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling activates a phosphatidylinositol-calcium second messenger system and generates a calcium-activated chloride current. Plays an important role in the regulation of synaptic plasticity and the modulation of the neural network activity. Interacts with RYR1, RYR2, ITPR1, SHANK1 and SHANK3. The PPXXF motif binds HOMER1, HOMER2 and HOMER3. Interacts with SIAH1 and TAMALIN. Interacts with NCDN. Interacts with NECAB2. Interacts with CAMK2A (By similarity). Widely distributed in neuronal cells of the central nervous system. Activated by quisqualate > glutamate > ibotenate > trans-1- aminocyclopentyl-1,3-dicarboxylate. Belongs to the G-protein coupled receptor 3 family.