Bombesin Receptor 3 Antibodies

The bombesin BB₃ receptor (BRS-3), encoded by BRS3, is a class A G protein-coupled receptor with no established endogenous ligand. The endogenous mammalian bombesin-related peptides gastrin-releasing peptide and neuromedin B have low affinity for BB₃. The receptor can couple to Gq/11, activating phospholipase C and increasing intracellular calcium. BB₃ is expressed in selected brain regions, including the hypothalamus, and has also been detected in pancreatic islets. In mice, loss of BRS-3 leads to increased food intake, reduced energy expenditure, and obesity, while pharmacological activation can stimulate glucose-dependent insulin secretion in isolated islets. The mechanisms governing BB₃ phosphorylation, desensitization, and trafficking are less well characterized than those of the BB₂ receptor. The selective small-molecule agonist MK-5046 reached phase 1 testing, in which transient increases in blood pressure were observed. No BB₃-selective ligand is currently approved for therapeutic use. BB3 receptor desensitization, β-arrestin recruitment and internalization are regulated by phosphorylation of carboxyl-terminal threonine360/serine361 (pT360/pS361-BB3),  threonine363/threonine364 (pT363/pT364-BB3) and threonine370 (pT370-BB3). This nomenclature refers to the human BB3 receptor. For more information on BB3 pharmacology please refer to the IUPHAR database. For further reading refer to:

Jensen RT, Battey JF, Spindel ER, Benya RV. International Union of Pharmacology. LXVIII. Mammalian bombesin receptors: nomenclature, distribution, pharmacology, signaling, and functions in normal and disease states. Pharmacol Rev. 2008 Mar;60(1):1-42. doi: 10.1124/pr.107.07108. Epub 2007 Nov 30. PMID: 18055507; PMCID: PMC2517428.