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. GPR110 (G protein-coupled receptor 110), also known as PGR19, is a 911 amino acid protein that belongs to the G-protein coupled receptor 2 family and LN-TM7 subfamily. Characterized as an adhesion GPCR, GPR110 is a multipass membrane-bound protein with a long amino-terminus that contains multiple domains. One of these domains is the GPCR proteolytic site (GPS), which is essential for proteolytic cleavage of the amino-terminus and for cell surface expression.