This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: 104/6/770    most recent CIRCRESAHA.108.187880v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Soto, D. Articles by Xiang, Y. Search for Related Content PubMed PubMed Citation Articles by Soto, D. Articles by Xiang, Y. Related Collections Cell biology/structural biology Cell signalling/signal transduction Imaging

(Circulation Research. 2009;104:770.)
© 2009 American Heart Association, Inc.

Cellular Biology

Dynamic Protein Kinase A Activities Induced by β-Adrenoceptors Dictate Signaling Propagation for Substrate Phosphorylation and Myocyte Contraction

Dagoberto Soto, Vania De Arcangelis, Jin Zhang, Yang Xiang

From the Department of Molecular and Integrative Physiology (D.S., V.D.A., Y.X.), University of Illinois at Urbana Champaign; and Department of Pharmacology and Molecular Sciences (J.Z.), John Hopkins University School of Medicine, Baltimore, Md.

Correspondence to Yang Xiang, Department of Molecular and Integrative Physiology, University of Illinois at Urbana Champaign, 407 S Goodwin Ave, Urbana, IL 61801. E-mail kevinyx{at}illinois.edu

cAMP/protein kinase (PK)A activation represents a key signaling mechanism for neurohormonal stimulation of diversified physiological processes. Using real-time, fluorescence resonance energy transfer-based imaging of PKA activity in neonatal cardiac myocytes, we report that sustained activation of PKA induced by β-adrenoceptor (βAR) dictates signaling propagation for substrate phosphorylation and myocyte contraction. Activation of βARs in wild-type myocytes induces strong and sustained PKA activities, which are rapidly attenuated on washing away agonist or adding antagonist to the cells. The sustained PKA activities promote signaling propagation to the sarcoplasmic reticulum for phosphorylation of phospholamban and increases in myocyte contraction. Addition of antagonist after βAR stimulation significantly attenuates PKA phosphorylation of phospholamban and rapidly reduces contraction rate increases. Moreover, stimulation of β₁AR subtype induces PKA activities similar to those in wild-type cells. In contrast, stimulation of β₂AR subtype induces strong initial activation of PKA similar to those induced by β₁AR; however, the activities are rapidly decreased to baseline levels. The transient PKA activities are sufficient for phosphorylation of the overexpressed β₂ARs under agonist stimulation, but not phospholamban. Further analysis reveals that phosphodiesterase 4 is the major family that shapes PKA activities under βAR stimulation. Inhibition of phosphodiesterase 4 extends β₂AR-induced PKA activities, promotes PKA phosphorylation of phospholamban, and ultimately enhances myocyte contraction responses. Together, our data have revealed insights into kinetics of PKA activities in signaling propagation under neurohormonal stimulation.

Key Words: protein kinase A phosphorylation • adrenergic receptor • phospholamban • contraction

This article has been cited by other articles:

				R. Liu, B. Ramani, D. Soto, V. De Arcangelis, and Y. Xiang Agonist Dose-dependent Phosphorylation by Protein Kinase A and G Protein-coupled Receptor Kinase Regulates {beta}2 Adrenoceptor Coupling to Gi Proteins in Cardiomyocytes J. Biol. Chem., November 20, 2009; 284(47): 32279 - 32287. [Abstract] [Full Text] [PDF]