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, such as adenylate cyclase. Signaling inhibits adenylate cyclase activity (By similarity). Signaling stimulates TRPM1 channel activity and Ca(2+) uptake. Required for normal vision. Homodimer. Subject to trafficking from the endoplasmic reticulum to the Golgi apparatus and then to the cell membrane. Detected in melanocytes. The disease is caused by variants affecting the gene represented in this entry. Belongs to the G-protein coupled receptor 3 family.