neuromedin B receptor, member of the class A family of seven-transmembrane G protein-coupled receptors
The neuromedin B receptor (NMBR), also known as BB1, is a G-protein coupled receptor whose endogenous ligand is the neuropeptide neuromedin B. Neuromedin B is a potent mitogen and growth factor for normal and cancerous lung and for gastrointestinal epithelial tissues. NMBR is widely distributed in the CNS, with especially high levels in olfactory nucleus and thalamic regions. The receptor couples primarily to a pertussis-toxin-insensitive G protein of the Gq/11 family, which leads to the activation of phospholipase C. NMBR belongs to the bombesin subfamily of G-protein coupled receptors, whose members also include gastrin-releasing peptide receptor (GRPR) and bombesin receptor subtype 3 (BRS-3). Bombesin is a tetradecapeptide, originally isolated from frog skin.
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.",