bombesin receptor subtype 3, member of the class A family of seven-transmembrane G protein-coupled receptors
BRS-3 is classified as an orphan receptor and belongs to the bombesin subfamily of G-protein coupled receptors, whose members also include neuromedin B receptor (NMBR) and gastrin-releasing peptide receptor (GRPR). Bombesin is a tetradecapeptide, originally isolated from frog skin. Mammalian bombesin-related peptides are widely distributed in the gastrointestinal and central nervous systems. The bombesin family receptors couple primarily to the G proteins of G(q/11) family. BRS-3 interacts with known naturally-occurring bombesin-related peptides with low affinity; however, no endogenous high-affinity ligand to the receptor has been identified. BRS-3 is suggested to play a role in sperm cell division and maturation.
Comment:based on the structures of some class A family members with bound ligands (peptides or chemicals), agonists, or antagonists
Comment:Small-molecule chemical ligands tend to bind deeper within the receptor core, compared to a peptide ligand neurotensin, which binds towards the extracellular surface of its receptor.
Jiyao W et al.(2023). "The conserved domain database in 2023.",