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Blood, 1 September 2007, Vol. 110, No. 5, pp. 1475-1482. Prepublished online as a Blood First Edition Paper on March 28, 2007; DOI 10.1182/blood-2006-10-052522. This Article Full Text (PDF) All Versions of this Article: blood-2006-10-052522v1 110/5/1475    most recent Alert me when this article is cited Alert me if a correction is posted 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 Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Zhang, W. Articles by Colman, R. W Search for Related Content PubMed PubMed Citation Articles by Zhang, W. Articles by Colman, R. W Social Bookmarking                   What's this?  Previous Article  |  Next Article  Submitted October 20, 2006 Accepted March 20, 2007 Thrombin regulates intracellular cAMP concentration in human platelets through phosphorylation/activation of PDE3A Wei Zhang and Robert W Colman* Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, United States * Corresponding author; email: colmanr{at}temple.edu. Thrombin-induced cAMP reduction potentates several steps in platelet activation, including Ca++ mobilization, cytoskeletal reorganization, and fibrinogen receptor conformation. We now reinvestigate the signaling pathways by which intracellular cAMP content is controlled following platelet activation by thrombin. When washed human platelets were stimulated with thrombin, cAMP-dependent phosphodiesterase (PDE3A) activity was significantly increased. A non-selective PDE inhibitor, 3-Isobutyl-1-methylxanthine (IBMX), and the PDE3 selective inhibitors milrinone and cilostazol each suppressed thrombin-induced cAMP-dependent PDE responses, but not two different PDE2 inhibitors. Selective inhibition of PDE3A resulted in reversal of thrombin-induced cAMP reduction indicating that thrombin activated PDE3A. In synergy with inhibition of adenylate cyclase by thrombin, activated PDE3A accelerates cAMP hydrolysis and maximally reduces the cAMP content. Thrombin-induced PDE3A activation was diminished concomitantly with dephosphorylation of PDE3A by protein-phosphatase 1 (PP1). An Akt inhibitor blocked PDE3A activation and constrained thrombin-induced cAMP reduction. A P2Y12 inhibitor also reduced thrombin-induced cAMP reduction. The combination of both reversed cAMP decrease by thrombin. Thrombin-mediated phosphorylated PDE3A was isolated by liquid chromatography, detected by a mAb against Akt-phosphorylated substrate, and verified by immunoprecipitation study. The predominant isoform phosphorylated by Akt was the 136 kDa species. We suggest that activation/phosphorylation of PDE3A via Akt signaling pathway participates in regulating cAMP during thrombin activation of platelets. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: R. W. Hunter, C. MacKintosh, and I. Hers Protein Kinase C-mediated Phosphorylation and Activation of PDE3A Regulate cAMP Levels in Human Platelets J. Biol. Chem., May 1, 2009; 284(18): 12339 - 12348. [Abstract] [Full Text] [PDF] S. S. Smyth, D. S. Woulfe, J. I. Weitz, C. Gachet, P. B. Conley, S. G. Goodman, M. T. Roe, A. Kuliopulos, D. J. Moliterno, P. A. French, et al. G-Protein-Coupled Receptors as Signaling Targets for Antiplatelet Therapy Arterioscler Thromb Vasc Biol, April 1, 2009; 29(4): 449 - 457. [Abstract] [Full Text] [PDF] D. Li, S. August, and D. S. Woulfe GSK3{beta} is a negative regulator of platelet function and thrombosis Blood, April 1, 2008; 111(7): 3522 - 3530. [Abstract] [Full Text] [PDF]

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