Bombesin Receptor 2 Antibodies

The bombesin BB₂ receptor, also known as the gastrin-releasing peptide receptor (GRPR), is a class A G protein-coupled receptor encoded by GRPR. Gastrin-releasing peptide (GRP) is its preferred endogenous agonist, and the amphibian peptide bombesin also activates the receptor with high potency. BB₂ couples predominantly to Gq/11, activating phospholipase C and increasing intracellular calcium. The receptor is expressed in the central nervous system, gastrointestinal tract, and pancreas, where it contributes to neuronal signaling, gastrointestinal motility, and secretion. Agonist stimulation induces phosphorylation of serine and threonine residues in the receptor’s C-terminal tail and promotes β-arrestin recruitment, desensitization, and internalization. BB₂ is overexpressed in subsets of prostate and breast cancers, making it a target for molecular imaging and radionuclide therapy. The antagonist-based radioligand gallium-68–labeled NeoB has been studied clinically as a PET tracer for BB₂-expressing tumors. Its therapeutic counterpart, lutetium-177–labeled NeoB, has entered phase 1/2a testing in patients with advanced solid tumors. No BB₂-targeted drug is currently approved for therapeutic use. BB2 receptor desensitization, β-arrestin recruitment and internalization are regulated by phosphorylation of carboxyl-terminal threonine359/serine360 (pT359/pS360-BB2) and serine363/threonine364 (pS363/pT364-BB2). This nomenclature refers to the human BB2 receptor. This phosphorylation motif is highly conserved across species but corresponds to pT360/pS361-BB2 and pS364/pT365-BB2 in mice and rats. For more information on BB2 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.