dc.contributor.author | PRESTON, ROGER | en |
dc.contributor.author | O'DONNELL, JAMES | en |
dc.contributor.author | JOHNSON, JENNIFER | en |
dc.contributor.author | HARMON, SHONA | en |
dc.contributor.author | NI AINLE, FIONNUALA | en |
dc.date.accessioned | 2010-11-12T10:33:50Z | |
dc.date.available | 2010-11-12T10:33:50Z | |
dc.date.issued | 2008 | en |
dc.date.submitted | 2008 | en |
dc.identifier.citation | Harmon, S, Preston, RJ, Ainle, FN, Johnson, JA, Cunningham, MS, Smith, OP, White, B, O'Donnell, JS, Dissociation of activated protein C functions by elimination of protein S cofactor enhancement., The Journal of Biological Chemistry, 283, 45, 2008, 30531 - 30539 | en |
dc.identifier.issn | 0021-9258 | en |
dc.identifier.other | Y | en |
dc.identifier.uri | http://hdl.handle.net/2262/41144 | |
dc.description | PUBLISHED | en |
dc.description.abstract | Activated protein C (APC) plays a critical anticoagulant role in vivo by inactivating procoagulant factor Va and factor VIIIa and thus down-regulating thrombin generation. In addition, APC bound to the endothelial cell protein C receptor can initiate protease-activated receptor-1 (PAR-1)-mediated cytoprotective signaling. Protein S constitutes a critical cofactor for the anticoagulant function of APC but is not known to be involved in regulating APC-mediated protective PAR-1 signaling. In this study we utilized a site-directed mutagenesis strategy to characterize a putative protein S binding region within the APC Gla domain. Three single amino acid substitutions within the APC Gla domain (D35T, D36A, and A39V) were found to mildly impair protein S-dependent anticoagulant activity (<2-fold) but retained entirely normal cytoprotective activity. However, a single amino acid substitution (L38D) ablated the ability of protein S to function as a cofactor for this APC variant. Consequently, in assays of protein S-dependent factor Va proteolysis using purified proteins or in the plasma milieu, APC-L38D variant exhibited minimal residual anticoagulant activity compared with wild type APC. Despite the location of Leu-38 in the Gla domain, APC-L38D interacted normally with endothelial cell protein C receptor and retained its ability to trigger PAR-1 mediated cytoprotective signaling in a manner indistinguishable from that of wild type APC. Consequently, elimination of protein S cofactor enhancement of APC anticoagulant function represents a novel and effective strategy by which to separate the anticoagulant and cytoprotective functions of APC for potential therapeutic gain. | en |
dc.description.sponsorship | This work was supported by a Health Research Board Fellowship PD/2006/24 (to R. J. S. P.), an Irish Heart Foundation grant (to J. S. O. D.), a Children's Medical Research Foundation Award (to F. N. A. and O. P. S.), and Science Foundation Ireland President of Ireland Young Researcher Award 06/Y12/0925 (to J. S. O. D.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked ?advertisement? in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. | en |
dc.format.extent | 30531 | en |
dc.format.extent | 30539 | en |
dc.language.iso | en | en |
dc.relation.ispartofseries | The Journal of Biological Chemistry | en |
dc.relation.ispartofseries | 283 | en |
dc.relation.ispartofseries | 45 | en |
dc.rights | Y | en |
dc.subject | Clinical medicine | en |
dc.subject | Hematology | en |
dc.subject | anticoagulant function | en |
dc.title | Dissociation of activated protein C functions by elimination of protein S cofactor enhancement. | en |
dc.type | Journal Article | en |
dc.type.supercollection | scholarly_publications | en |
dc.type.supercollection | refereed_publications | en |
dc.identifier.peoplefinderurl | http://people.tcd.ie/prestonr | en |
dc.identifier.peoplefinderurl | http://people.tcd.ie/jodonne | en |
dc.identifier.rssinternalid | 55649 | en |
dc.identifier.doi | http://dx.doi.org/10.1074/jbc.M802338200 | en |
dc.identifier.rssuri | http://dx.doi.org/10.1074/jbc.M802338200 | en |
dc.contributor.sponsor | Health Research Board (HRB) | en |