title: Active tissue factor pathway inhibitor is expressed on the surface of coated platelets.
abstract: The incorporation of blood-borne forms of tissue factor (TF) into a growing blood clot is necessary for normal fibrin generation and stabilization of the blood clot. Tissue factor pathway inhibitor (TFPI) is the primary physiologic inhibitor of tissue factor and is present within platelets. Expression of TFPI on the platelet surface may be the optimal location for it to abrogate blood-borne TF activity that incorporates within the blood clot, balancing the need for adequate hemostasis while preventing development of occlusive thrombosis. TFPI is produced by megakaryocytes but is not expressed on the platelet surface. Activation of platelets with thrombin receptor activation peptide does not cause release or surface expression of TFPI, demonstrating that TFPI is not stored within platelet alpha granules. TFPI is expressed on the platelet surface following dual-agonist activation with convulxin plus thrombin to produce coated platelets. In association with its expression on the surface of coated platelets TFPI is also released in microvesicles or as a soluble protein.
authors.affiliation: Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI 53201-2178, USA.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Maroney
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Haberichter
authors.forename: Paul
authors.initials: P
authors.lastname: Friese
authors.forename: Maureen L
authors.initials: ML
authors.lastname: Collins
authors.forename: Josephine P
authors.initials: JP
authors.lastname: Ferrel
authors.forename: George L
authors.initials: GL
authors.lastname: Dale
authors.forename: Alan E
authors.initials: AE
authors.lastname: Mast
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism; D008533:Megakaryocytes / Q000378:metabolism; D051379:Mice; D020033:Protein Isoforms / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D012995:Solubility; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D007527:Isoenzymes; D008074:Lipoproteins; D020033:Protein Isoforms; D012333:RNA, Messenger; C051928:lipoprotein-associated coagulation inhibitor; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase