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. GPR101 (G protein-coupled receptor 101), also known as GPCR6, is a 508 amino acid multi-pass membrane protein that belongs to the G-protein coupled receptor 1 family. GPR101 functions as an orphan receptor that is thought to play a role in signaling events throughout the cell. Expressed predominantly in brain, GPR101 participates in a wide range of activities in the CNS via modulation of cAMP levels.