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Blood, 1 December 2007, Vol. 110, No. 12, pp. 3909-3916. Prepublished online as a Blood First Edition Paper on September 6, 2007; DOI 10.1182/blood-2007-06-096651. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2007-06-096651v1 110/12/3909    most recent 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 Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Bae, J.-S. Articles by Rezaie, A. R. Search for Related Content PubMed PubMed Citation Articles by Bae, J.-S. Articles by Rezaie, A. R. Related Collections Hemostasis, Thrombosis, and Vascular Biology Signal Transduction Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  HEMOSTASIS, THROMBOSIS, AND VASCULAR BIOLOGY The ligand occupancy of endothelial protein C receptor switches the protease-activated receptor 1-dependent signaling specificity of thrombin from a permeability-enhancing to a barrier-protective response in endothelial cells Jong-Sup Bae1, Likui Yang1, Chandrashekhara Manithody1, and Alireza R. Rezaie1 1 Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, MO Recent studies have indicated that activated protein C (APC) may exert its cytoprotective and anti-inflammatory activities through the endothelial protein C receptor (EPCR)-dependent cleavage of protease-activated receptor 1 (PAR-1) on vascular endothelial cells. Noting that (1) the activation of protein C on endothelial cells requires thrombin, (2) relative to APC, thrombin cleaves PAR-1 with approximately 3 to 4 orders of magnitude higher catalytic efficiency, and (3) PAR-1 is a target for the proinflammatory activity of thrombin, it is not understood how APC can elicit a protective signaling response through the cleavage of PAR-1 when thrombin is present. In this study, we demonstrate that EPCR is associated with caveolin-1 in lipid rafts of endothelial cells and that its occupancy by the -carboxyglutamic acid (Gla) domain of protein C/APC leads to its dissociation from caveolin-1 and recruitment of PAR-1 to a protective signaling pathway through coupling of PAR-1 to the pertussis toxin–sensitive Gi-protein. Thus, when EPCR is bound by protein C, the PAR-1 cleavage-dependent protective signaling responses in endothelial cells can be mediated by either thrombin or APC. These results provide a new paradigm for understanding how PAR-1 and EPCR participate in protective signaling events in endothelial cells. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: R. A. Schuepbach, C. Feistritzer, L. F. Brass, and M. Riewald Activated protein C-cleaved protease activated receptor-1 is retained on the endothelial cell surface even in the presence of thrombin Blood, March 1, 2008; 111(5): 2667 - 2673. [Abstract] [Full Text] [PDF]

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