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Phosphorylation of coagulation factor XI by a casein kinase released by activated human platelets increases its susceptibility to activation by factor XIIa and thrombin.
Thromb Haemost. 1999 Oct; 82(4):1283-8.TH

Abstract

Previous studies suggest that activated platelets facilitate the cleavage of factor XI by both factor XIIa and thrombin. Extracellular phosphorylation is a mechanism by which the function of plasma proteins can be regulated. Phosphorylation is mediated by a casein kinase which is released by activated platelets concomitant with large amounts of ATP and Ca2+. The purpose of this study was to investigate if factor XI is phosphorylated by a platelet casein kinase and whether phosphorylation may affect its activation properties. It was shown that supernatants from platelets which contain platelet casein kinase phosphorylated factor XI. By Western blot analysis it was shown that phosphorylation of factor XI substantially increased its susceptibility to cleavage by factor XIIa, and, to a lesser extent, by thrombin. The generated factor XIa was functionally active in that it cleaved the chromogenic substrate S2366, and in that factor XIa-antithrombin and thrombin-antithrombin complexes were generated when phosphorylated factor XI was added to blood plasma. The present study indicates that platelet-mediated phosphorylation of factor XI enhances the cleavage of factor XI into XIa and that the generated XIa possesses functional activity. Phosphorylation of factor XI might be an essential regulatory mechanism by which platelets mediate amplification of the coagulation cascade.

Authors+Show Affiliations

Department of Clinical Immunology and Transfusion Medicine, University Hospital, Uppsala, Sweden. Kristina.Nilsson_Ekdahl@KlinImm.uu.seNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10544914

Citation

Ekdahl, K N., et al. "Phosphorylation of Coagulation Factor XI By a Casein Kinase Released By Activated Human Platelets Increases Its Susceptibility to Activation By Factor XIIa and Thrombin." Thrombosis and Haemostasis, vol. 82, no. 4, 1999, pp. 1283-8.
Ekdahl KN, Elgue G, Nilsson B. Phosphorylation of coagulation factor XI by a casein kinase released by activated human platelets increases its susceptibility to activation by factor XIIa and thrombin. Thromb Haemost. 1999;82(4):1283-8.
Ekdahl, K. N., Elgue, G., & Nilsson, B. (1999). Phosphorylation of coagulation factor XI by a casein kinase released by activated human platelets increases its susceptibility to activation by factor XIIa and thrombin. Thrombosis and Haemostasis, 82(4), 1283-8.
Ekdahl KN, Elgue G, Nilsson B. Phosphorylation of Coagulation Factor XI By a Casein Kinase Released By Activated Human Platelets Increases Its Susceptibility to Activation By Factor XIIa and Thrombin. Thromb Haemost. 1999;82(4):1283-8. PubMed PMID: 10544914.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Phosphorylation of coagulation factor XI by a casein kinase released by activated human platelets increases its susceptibility to activation by factor XIIa and thrombin. AU - Ekdahl,K N, AU - Elgue,G, AU - Nilsson,B, PY - 1999/11/2/pubmed PY - 1999/11/2/medline PY - 1999/11/2/entrez SP - 1283 EP - 8 JF - Thrombosis and haemostasis JO - Thromb Haemost VL - 82 IS - 4 N2 - Previous studies suggest that activated platelets facilitate the cleavage of factor XI by both factor XIIa and thrombin. Extracellular phosphorylation is a mechanism by which the function of plasma proteins can be regulated. Phosphorylation is mediated by a casein kinase which is released by activated platelets concomitant with large amounts of ATP and Ca2+. The purpose of this study was to investigate if factor XI is phosphorylated by a platelet casein kinase and whether phosphorylation may affect its activation properties. It was shown that supernatants from platelets which contain platelet casein kinase phosphorylated factor XI. By Western blot analysis it was shown that phosphorylation of factor XI substantially increased its susceptibility to cleavage by factor XIIa, and, to a lesser extent, by thrombin. The generated factor XIa was functionally active in that it cleaved the chromogenic substrate S2366, and in that factor XIa-antithrombin and thrombin-antithrombin complexes were generated when phosphorylated factor XI was added to blood plasma. The present study indicates that platelet-mediated phosphorylation of factor XI enhances the cleavage of factor XI into XIa and that the generated XIa possesses functional activity. Phosphorylation of factor XI might be an essential regulatory mechanism by which platelets mediate amplification of the coagulation cascade. SN - 0340-6245 UR - https://www.unboundmedicine.com/medline/citation/10544914/Phosphorylation_of_coagulation_factor_XI_by_a_casein_kinase_released_by_activated_human_platelets_increases_its_susceptibility_to_activation_by_factor_XIIa_and_thrombin_ DB - PRIME DP - Unbound Medicine ER -