Current bombesin receptor nomenclature and general characteristics See text for references.
| Receptor Code | Mammalian Bombesin Receptor | ||
|---|---|---|---|
| BB1 | BB2 | BB3 | |
| Previous names | NMB-R, NMB-preferring receptor | GRP-R, GRP-preferring receptor | BRS-3, bombesin receptor subtype 3 |
| Cloned from mammals | Human, rat, mouse, monkey | Human, rat, mouse, monkey, chimpanzee, dog, sheep | Human, rat, mouse, monkey, sheep |
| Gene location | Chr 6p21 (human) | Chr Xp22 (human) | Chr Xq25 (human) |
| Structural information | 390 aa (human) | 384 aa (human) | 399 aa (human) |
| Natural ligands | NMB > GRP | GRP > NMB | Unknown (low-affinity NMB, GRP, all Bn natural related peptides) |
| Selective agonist | NMB, NMB30 | GRP | [d-Tyr6,Apa-4Cl11,Phe13,Nle14]bombesin 6–14, Ac-Phe,Trp,Ala,His(tBzl),Nip,Gly,Arg-NH2 |
| Selective antagonists | PD 168368 | [d-Phe6,Cpa14,ψ13–14]Bn6–14, JMV641, JMV594, BW2258U89, Ac-GRP20–26 methyl ester | None |
| Principal transduction | Gq/11 | Gq/11 | Gq/11 |
| Preferred radioligand | 125I-BH-[d-Tyr0]-NMB, 125I-[Tyr4]-Bn | 125I-[GRP], 125I-[Tyr4]-Bn, 125I-[d-Tyr6]-Bn6–13 methyl ester | 125I- [d-Phe6,β-Ala11,Phe13,Nle14]Bn6–14 |
| Tissue functions | CNS (regulate TSH release, satiety), GI tract (motility); regulate stress responses | CNS (thermoregulation, regulate circadian rhythm, satiety); GI tract [hormone release, motility, regulate secretions (pancreas, gastric acid, islets)]; immunologic (chemoattractant, lymphocyte function); fetal development (lung) | Regulate energy homeostasis, glucose/insulin regulation; satiety; lung development and response to injury: present myenteric/submucosa ganglia, cells of Cajal proposed to be involved in GI motility |
| Diseases | Altered hypo-, hyperthyroidism; autocrine tumor growth factor (lung/colon tumors, carcinoids, others) | Tumor growth effects–morphogen, autocrine growth factor (lung, colon, prostate, breast, head-neck tumors, others); lung diseases (bronchopulmonary dysplasia, tobacco injury) | Tumor growth factor (lung, others) |
| Phenotype of knockout | Reduced hypothermic effect to NMB; abnormal behaviors, dysregulation of thyroid-pituitary axis, altered CNS 5-HT system with stress | Altered satiety, thermoregulation, abnormal behaviors, altered insulin release | Mild obesity, hypertension, impaired glucose metabolism reduced metabolic rate, increased feeding behavior, altered lung response to injury |
aa, amino acids