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. GPR174 (G protein-coupled receptor 174), also known as FKSG79, is a 333 amino acid multi-pass membrane protein that belongs to the G-protein coupled receptor 1 family and is thought to function as a receptor for G protein-coupled purines.