G protein-coupled receptors (GPRs), also known as seven transmembrane receptors, heptahelical receptors or 7TM receptors, comprise a superfamily of proteins that play a role in many different stimulus-response pathways. G protein coupled receptors translate extracellular signals into intracellular signals (G protein activation) and they respond to a variety of signaling molecules, such as hormones and neurotransmitters. GPR88 (G protein-coupled receptor 88), also known as STRG, is a 384 amino acid multi-pass membrane protein that localizes to the cell membrane and belongs to the G protein coupled receptor family. Expressed exclusively in striatum, GPR88 functions as an orphan receptor that may be involved in signaling pathways throughout the cell. Human GPR88 shares 95% sequence identity with its rat counterpart, suggesting a conserved role between species.