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. GPR97 (G protein-coupled receptor 97), also known as PB99 or PGR26, is a 549 amino acid multi-pass membrane protein that contains one GPS domain and belongs to the G-protein coupled receptor 2 family. GPR97 functions as an orphan receptor that is thought to play a role in signaling events throughout the cell.