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Selective interference of beta-arrestin 1 with kappa and delta but not mu opioid receptor/G protein coupling

Z J Cheng1, Q M Yu, Y L Wu

  • 1Shanghai Institute of Cell Biology, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.

The Journal of Biological Chemistry
|September 12, 1998
PubMed

Insights

Beta-arrestin 1 (beta-arr1) differentially regulates opioid receptor signaling. It attenuates kappa and delta opioid receptor responses by interfering with G protein coupling, but not mu opioid receptors.

Area of Science:

  • Pharmacology
  • Molecular Biology
  • Cell Signaling

Background:

  • Opioid receptors (kappa, delta, mu) mediate diverse physiological effects.
  • Beta-arrestin 1 (beta-arr1) is known to regulate G protein-coupled receptor (GPCR) signaling.
  • The specific role of beta-arr1 in modulating opioid receptor subtypes requires further elucidation.

Purpose of the Study:

  • To investigate the role of beta-arrestin 1 (beta-arr1) in the regulation of kappa, delta, and mu opioid receptor responsiveness.
  • To determine how beta-arr1 expression affects opioid receptor-mediated signaling pathways, including cAMP production and G protein activation.
  • To identify the structural determinants within opioid receptors responsible for beta-arr1 interaction.

Main Methods:

  • Human embryonic kidney 293 cells were cotransfected with opioid receptor subtypes and beta-arrestin 1.
  • Functional assays measured cAMP production and G protein activation in response to specific opioid receptor agonists.
  • Site-directed mutagenesis was employed to truncate or modify opioid receptor carboxyl termini.

Main Results:

  • Beta-arrestin 1 (beta-arr1) significantly attenuated kappa and delta opioid receptor-mediated inhibition of cAMP production and G protein activation.
  • Beta-arr1 expression increased EC50 values by 100-fold for kappa and delta agonists and reduced maximal responses by 30-40%.
  • Mu opioid receptor-mediated signaling remained unaffected by beta-arr1 coexpression, and truncation/modification of receptor carboxyl termini altered beta-arr1 sensitivity.

Conclusions:

  • Beta-arrestin 1 (beta-arr1) differentially regulates opioid receptor responsiveness, primarily by interfering with kappa and delta receptor/G protein coupling.
  • The carboxyl terminus of opioid receptors, including its phosphorylation status, is critical for mediating the effects of beta-arr1.
  • These findings highlight a mechanism for differential modulation of opioid receptor signaling pathways by beta-arrestin 1.

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