Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
The Journal of Biological Chemistry
Year: 2008  |  Volume: 283  |  Issue: 4  |  Page No.: 1799 - 1807

Norepinephrine- and Epinephrine-induced Distinct β2-Adrenoceptor Signaling Is Dictated by GRK2 Phosphorylation in Cardiomyocytes

Yongyu Wang, Vania De Arcangelis, Xiaoguang Gao, Biswarathan Ramani, Yi-sook Jung and Yang Xiang    

Abstract: Agonist-dependent activation of G protein-coupled receptors induces diversified receptor cellular and signaling properties. Norepinephrine (NE) and epinephrine (Epi) are two endogenous ligands that activate adrenoceptor (AR) signals in a variety of physiological stress responses in animals. Here we use cardiomyocyte contraction rate response to analyze the endogenous β2AR signaling induced by Epi or NE in cardiac tissue. The Epi-activated β2AR induced a rapid contraction rate increase that peaked at 4 min after stimulation. In contrast, the NE-activated β2AR induced a much slower contraction rate increase that peaked at 10 min after stimulation. Whereas both drugs activated β2AR coupling to Gs proteins, only Epi-activated receptors were capable of coupling to Gi proteins. Subsequent studies showed that the Epi-activated β2AR underwent a rapid phosphorylation by G protein-coupled receptor kinase 2 (GRK2) and subsequent dephosphorylation on serine residues 355 and 356, which was critical for sufficient receptor recycling and Gi coupling. In contrast, the NE-activated β2ARs underwent slow GRK2 phosphorylation, receptor internalization and recycling, and failed to couple to Gi. Moreover, inhibiting β2AR phosphorylation by βARK C terminus or dephosphorylation by okadaic acid prevented sufficient recycling and Gi coupling. Together, our data revealed that distinct temporal phosphorylation of β2AR on serine 355 and 356 by GRK2 plays a critical role for dictating receptor cellular events and signaling properties induced by Epi or NE in cardiomyocytes. This study not only helps us understand the endogenous agonist-dependent β2AR signaling in animal heart but also offers an example of how G protein-coupled receptor signaling may be finely regulated by GRK in physiological settings.

View Fulltext    |   Related Articles   |   Back
   
 
 
 
  Related Articles

No Article Found
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility