Beta-blockers alprenolol and carvedilol stimulate beta-arrestin-mediated EGFR transactivation

Proc Natl Acad Sci U S A. 2008 Sep 23;105(38):14555-60. doi: 10.1073/pnas.0804745105. Epub 2008 Sep 11.

Abstract

Recent evidence suggests that binding of agonist to its cognate receptor initiates not only classical G protein-mediated signaling, but also beta-arrestin-dependent signaling. One such beta-arrestin-mediated pathway uses the beta(1)-adrenergic receptor (beta(1)AR) to transactivate the EGFR. To determine whether beta-adrenergic ligands that do not activate G protein signaling (i.e., beta-blockers) can stabilize the beta(1)AR in a signaling conformation, we screened 20 beta-blockers for their ability to stimulate beta-arrestin-mediated EGFR transactivation. Here we show that only alprenolol (Alp) and carvedilol (Car) induce beta(1)AR-mediated transactivation of the EGFR and downstream ERK activation. By using mutants of the beta(1)AR lacking G protein-coupled receptor kinase phosphorylation sites and siRNA directed against beta-arrestin, we show that Alp- and Car-stimulated EGFR transactivation requires beta(1)AR phosphorylation at consensus G protein-coupled receptor kinase sites and beta-arrestin recruitment to the ligand-occupied receptor. Moreover, pharmacological inhibition of Src and EGFR blocked Alp- and Car-stimulated EGFR transactivation. Our findings demonstrate that Alp and Car are ligands that not only act as classical receptor antagonists, but can also stimulate signaling pathways in a G protein-independent, beta-arrestin-dependent fashion.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adrenergic beta-Antagonists / pharmacology*
  • Alprenolol / pharmacology*
  • Animals
  • Arrestins / metabolism*
  • Carbazoles / pharmacology*
  • Carvedilol
  • Cell Line, Transformed
  • Dose-Response Relationship, Drug
  • Enzyme Activation / drug effects
  • Enzymes / metabolism
  • ErbB Receptors / metabolism*
  • Erlotinib Hydrochloride
  • Genes, erbB-1 / genetics
  • Heart / drug effects
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Phosphorylation / drug effects
  • Propanolamines / pharmacology*
  • Quinazolines / pharmacology
  • Signal Transduction / drug effects
  • Transcriptional Activation / drug effects*
  • beta-Arrestins

Substances

  • Adrenergic beta-Antagonists
  • Arrestins
  • Carbazoles
  • Enzymes
  • Propanolamines
  • Quinazolines
  • beta-Arrestins
  • Carvedilol
  • Alprenolol
  • Erlotinib Hydrochloride
  • ErbB Receptors
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3