bombesin receptor signaling pathway

Definition

Target type: biologicalprocess

A G protein-coupled receptor signaling pathway initiated by a bombesin binding to its receptor, and ending with the regulation of a downstream cellular process, e.g. transcription. [GOC:mah]

The bombesin receptor signaling pathway is a complex cascade of events initiated by the binding of bombesin-like peptides to G protein-coupled receptors (GPCRs) on the cell surface. These receptors, known as bombesin receptors (BB) or gastrin-releasing peptide receptors (GRPR), belong to the bombesin receptor family. The activation of these receptors triggers a series of intracellular signaling events, leading to various cellular responses.

The process begins with the binding of bombesin or its analogs to the extracellular domain of the receptor. This interaction induces a conformational change in the receptor, leading to the activation of the intracellular signaling cascade. The activated receptor interacts with heterotrimeric G proteins, specifically Gq/11 proteins, leading to the dissociation of the alpha subunit from the beta-gamma subunit complex.

The activated alpha subunit of Gq/11 protein stimulates the activity of phospholipase C-beta (PLC-β), an enzyme that hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol triphosphate (IP3). DAG activates protein kinase C (PKC), a serine/threonine kinase, while IP3 binds to IP3 receptors on the endoplasmic reticulum (ER), causing the release of calcium ions (Ca2+) into the cytoplasm.

The increase in intracellular Ca2+ levels, along with DAG-mediated activation of PKC, further amplifies the signaling cascade. This leads to the activation of various downstream signaling pathways, including the mitogen-activated protein kinase (MAPK) pathway, the phosphoinositide 3-kinase (PI3K)/Akt pathway, and the Ras/Raf/MEK/ERK pathway.

These signaling pathways regulate a wide range of cellular functions, including cell proliferation, differentiation, migration, and survival. The bombesin receptor signaling pathway is implicated in various physiological and pathological processes, including gastrointestinal function, neurotransmission, and cancer development.

The precise biological effects of bombesin receptor signaling vary depending on the cell type, the specific receptor subtype involved, and the context of the signaling cascade. However, the overall effect of this pathway is to promote cell growth, survival, and proliferation, making it a potential target for therapeutic intervention in various diseases, including cancer.'
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Proteins (2)

Compounds (9)