positive regulation of histamine secretion by mast cell

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of histamine secretion by mast cell. [GO_REF:0000058, GOC:als, GOC:TermGenie, PMID:18253931]

Positive regulation of histamine secretion by mast cells is a complex process involving a cascade of signaling events. It begins with the activation of mast cells by various stimuli, including allergens, pathogens, and certain medications. This activation triggers a series of intracellular signaling pathways, leading to the release of histamine from preformed granules within the mast cell.

1. **Stimulus Recognition:** Mast cells express a diverse array of receptors on their surface, including FcεRI (high-affinity IgE receptor), FcγRI (high-affinity IgG receptor), and TLRs (Toll-like receptors). Binding of allergens, pathogens, or other stimuli to these receptors initiates the signaling cascade.

2. **Signal Transduction:** Upon receptor engagement, intracellular signaling pathways are activated. The most prominent pathway involves the activation of tyrosine kinases such as Syk and Lyn. These kinases phosphorylate downstream signaling molecules, including phospholipase Cγ (PLCγ).

3. **Calcium Release:** PLCγ hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol (DAG) and inositol trisphosphate (IP3). IP3 binds to its receptor on the endoplasmic reticulum (ER), triggering the release of calcium ions (Ca2+) into the cytoplasm.

4. **Granule Exocytosis:** The increase in intracellular Ca2+ concentration activates protein kinase C (PKC), which phosphorylates various proteins involved in granule exocytosis. This includes the fusion of granules containing histamine with the plasma membrane, releasing histamine into the extracellular environment.

5. **Histamine Release:** Histamine is a potent vasoactive amine that plays a crucial role in inflammatory responses. It exerts its effects by binding to histamine receptors (H1, H2, and H3) on target cells, leading to a range of physiological responses such as vasodilation, bronchoconstriction, and increased mucus secretion.

In summary, positive regulation of histamine secretion by mast cells involves a complex interplay of receptors, signaling molecules, and intracellular processes. This process is tightly regulated to ensure an appropriate inflammatory response to diverse stimuli.'
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Proteins (1)

Compounds (2)