Target type: molecularfunction
Combining with bombesin to initiate a change in cell activity. [GOC:ai]
Bombesin receptor activity refers to the ability of a protein to bind and respond to bombesin-like peptides, a family of neuropeptides that exert diverse biological functions, including neurotransmission, cell proliferation, and regulation of gastrointestinal function. Bombesin receptors are G protein-coupled receptors (GPCRs), meaning they signal through heterotrimeric G proteins upon ligand binding. The activation of these receptors leads to the activation of downstream signaling cascades, ultimately mediating cellular responses.
Bombesin receptors, also known as gastrin-releasing peptide receptors (GRPRs), are expressed in a variety of tissues, including the brain, lungs, gastrointestinal tract, pancreas, and skin. Their diverse distribution reflects their diverse biological roles.
**Molecular Function:**
- **Ligand Binding:** Bombesin receptors bind to bombesin-like peptides, including bombesin, gastrin-releasing peptide (GRP), and neuromedin B. These peptides exhibit varying affinities for different receptor subtypes.
- **G Protein Coupling:** Upon ligand binding, bombesin receptors activate G proteins, primarily Gq/11, leading to the activation of phospholipase C (PLC).
- **Phospholipase C Activation:** PLC hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol trisphosphate (IP3).
- **Calcium Signaling:** IP3 increases intracellular calcium levels by releasing calcium from intracellular stores.
- **Protein Kinase C Activation:** DAG activates protein kinase C (PKC), a family of serine/threonine kinases involved in various cellular processes.
- **Other Signaling Pathways:** Bombesin receptor activation also triggers other signaling pathways, including the mitogen-activated protein kinase (MAPK) pathway and the phosphoinositide 3-kinase (PI3K) pathway.
**Biological Functions:**
- **Neurotransmission:** Bombesin receptors are involved in neurotransmission in the central and peripheral nervous systems, influencing behaviors like feeding, stress response, and anxiety.
- **Cell Proliferation:** Bombesin receptor activation promotes cell proliferation in a variety of cell types, including cancer cells.
- **Gastrointestinal Function:** Bombesin receptors regulate gastric acid secretion, pancreatic enzyme secretion, and intestinal motility.
- **Other Functions:** Bombesin receptors have been implicated in other biological processes, including wound healing, inflammation, and pain perception.
**Clinical Significance:**
- **Cancer Therapeutics:** Bombesin receptors are overexpressed in various cancer types, making them potential targets for cancer diagnosis and therapy. Radiolabeled bombesin analogs have shown promise in imaging and treating certain cancers.
- **Gastrointestinal Disorders:** Bombesin receptor antagonists have been explored as potential therapeutic agents for gastrointestinal disorders, such as gastroesophageal reflux disease (GERD) and irritable bowel syndrome (IBS).
**Conclusion:**
Bombesin receptor activity plays a crucial role in diverse physiological processes, making these receptors important targets for drug development and therapeutic interventions.'
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Protein | Definition | Taxonomy |
---|---|---|
Bombesin receptor subtype-3 | A bombesin receptor subtype-3 that is encoded in the genome of human. [PRO:WCB, UniProtKB:P32247] | Homo sapiens (human) |
Neuromedin-B receptor | A neuromedin-B receptor that is encoded in the genome of human. [PRO:WCB, UniProtKB:P28336] | Homo sapiens (human) |
Compound | Definition | Classes | Roles |
---|---|---|---|
omeprazole | 5-methoxy-2-{[(4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl}-1H-benzimidazole : A member of the class of benzimidazoles that is 1H-benzimidazole which is substituted by a [4-methoxy-3,5-dimethylpyridin-2-yl)methyl]sulfinyl group at position 2 and a methoxy group at position 5. omeprazole : A racemate comprising equimolar amounts of (R)- and (S)-omeprazole. Omeprazole: A 4-methoxy-3,5-dimethylpyridyl, 5-methoxybenzimidazole derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits an H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. | aromatic ether; benzimidazoles; pyridines; sulfoxide | |
omeprazole sulfide | omeprazole sulfide: omeprazole metabolite; structure given in first source | benzimidazoles | |
harmalan | harmalan: structure given in first source | harmala alkaloid | |
1-methyl-6-methoxy-dihydro-beta-carboline | |||
harmine | harmine : A harmala alkaloid in which the harman skeleton is methoxy-substituted at C-7. Harmine: Alkaloid isolated from seeds of PEGANUM HARMALA; ZYGOPHYLLACEAE. It is identical to banisterine, or telepathine, from Banisteria caapi and is one of the active ingredients of hallucinogenic drinks made in the western Amazon region from related plants. It has no therapeutic use, but (as banisterine) was hailed as a cure for postencephalitic PARKINSON DISEASE in the 1920's. | harmala alkaloid | anti-HIV agent; EC 1.4.3.4 (monoamine oxidase) inhibitor; metabolite |
pd 176252 | PD 176252: a non-peptide gastrin-releasing peptide (BB2) receptor antagonist; structure in first source | ||
pd 168368 | PD 168368: a neuromedin B receptor antagonist; structure in first source | ||
bombesin | |||
mk 5046 |