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Blood, 1 December 2007, Vol. 110, No. 12, pp. 3900-3908. Prepublished online as a Blood First Edition Paper on August 28, 2007; DOI 10.1182/blood-2007-07-101469. This Article Full Text Full Text (PDF) All Versions of this Article: blood-2007-07-101469v1 110/12/3900    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 Pendurthi, U. R. Articles by Rao, L. V. M. Search for Related Content PubMed PubMed Citation Articles by Pendurthi, U. R. Articles by Rao, L. V. M. Related Collections Hemostasis, Thrombosis, and Vascular Biology Related Articles in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  HEMOSTASIS, THROMBOSIS, AND VASCULAR BIOLOGY Tissue factor activation: is disulfide bond switching a regulatory mechanism? Usha R. Pendurthi1, Samit Ghosh1, Samir K. Mandal1, and L. Vijaya Mohan Rao1 1 Biomedical Research Division, University of Texas Health Science Center at Tyler A majority of tissue factor (TF) on cell surfaces exists in a cryptic form (ie, coagulation function inactive) but retains its functionality in cell signaling. Recent studies have suggested that cryptic TF contains unpaired cysteine thiols and that activation involves the formation of the disulfide bond Cys186-Cys 209 and that protein disulfide isomerase (PDI) regulates TF coagulant and signaling activities by targeting this disulfide bond. This study was carried out to investigate the validity of this novel concept. Although treatment of MDA 231 tumor cells, fibroblasts, and stimulated endothelial cells with the oxidizing agent HgCl2 markedly increased the cell-surface TF coagulant activity, the increase is associated with increased anionic phospholipids at the cell surface. Annexin V, which binds to anionic phospholipids, attenuated the increased TF coagulant activity. It is noteworthy that treatment of cells with reducing agents also increased the cell surface TF activity. No evidence was found for either detectable expression of PDI at the cell surface or association of TF with PDI. Furthermore, reduction of PDI with the gene silencing had no effect on either TF coagulant or cell signaling functions. Overall, the present data undermine the recently proposed hypothesis that PDI-mediated disulfide exchange plays a role in regulating TF procoagulant and cell signaling functions. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Articles in Blood Online: Critical importance of the cell system when studying tissue factor de-encryption Hai Po Helena Liang and Philip J. Hogg Blood 2008 112: 912-913. [Full Text] [PDF] Response: Tissue factor de-encryption: the cell model system Usha R. Pendurthi and L. Vijaya Mohan Rao Blood 2008 112: 913. [Full Text] [PDF] Encryption remains cryptic James H. Morrissey Blood 2007 110: 3822-3823. [Full Text] [PDF] This article has been cited by other articles: H. Kothari, P. Sen, U. R. Pendurthi, and L. V. M. Rao Bovine protein disulfide isomerase-enhanced tissue factor coagulant function: is phospholipid contaminant in it the real culprit? Blood, March 15, 2008; 111(6): 3295 - 3296. [Full Text] [PDF]

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