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Gastric mucin secretion in response to beta-adrenergic G protein-coupled receptor activation is mediated by SRC

B L Słomiany1, A Słomiany

  • 1Research Center University of Medicine and Dentistry of New Jersey, Newark, NJ 07103-2400, USA. slomiabr@umdnj.edu

Journal of Physiology and Pharmacology : an Official Journal of the Polish Physiological Society
|June 30, 2005
PubMed

Insights

Beta-adrenergic stimulation of gastric mucin secretion involves epidermal growth factor receptor (EGFR) transactivation. Src kinase is crucial for this EGFR signaling pathway, highlighting EGFR

Area of Science:

  • Gastroenterology
  • Cellular Signaling
  • Molecular Biology

Background:

  • G protein-coupled receptor (GPCR) activation integrates regulatory signals into cellular pathways.
  • Receptor tyrosine kinases (RTKs) are often involved in these signaling integrations.
  • Gastric mucin secretion is regulated by complex cellular signaling cascades.

Purpose of the Study:

  • To investigate the role of epidermal growth factor receptor (EGFR) in beta-adrenergic agonist-induced gastric mucin secretion.
  • To elucidate the specific signaling molecules and kinases involved in this pathway.

Main Methods:

  • Utilized [(3)H]glucosamine-labeled gastric mucosal cells to measure mucin secretion.
  • Employed specific inhibitors: PD153035 (EGFR kinase inhibitor), wortmannin (PI3K inhibitor), and PP2 (Src kinase inhibitor).
  • Assessed the impact of these inhibitors on mucin secretion stimulated by beta-adrenergic agonists, cAMP, and forskolin.

Main Results:

  • Beta-adrenergic agonist-stimulated mucin secretion was inhibited by EGFR and PI3K inhibitors.
  • EGFR and PI3K inhibitors also reduced responses to cAMP and adenylate cyclase activator forskolin.
  • Src kinase inhibition blocked beta-adrenergic agonist-induced mucin secretion, indicating its role in EGFR transactivation.
  • ERK inhibition did not affect mucin secretion, suggesting it is not the primary pathway.

Conclusions:

  • EGFR acts as a critical convergence point for beta-adrenergic GPCR signaling in gastric mucin secretion.
  • Src kinase is essential for the EGFR transactivation required for this process.
  • The findings reveal a novel signaling mechanism regulating gastric mucosal defense.

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