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New functional test for the TFPIα cofactor activity of Protein S working in synergy with FV-Short

Dahlbäck, Björn LU ; Guo, Li Jun LU ; Zöller, Bengt LU and Tran, Sinh LU (2019) In Journal of Thrombosis and Haemostasis
Abstract

Essentials Protein S and FV-Short are synergistic cofactors to Tissue Factor Pathway Inhibitor α (TFPIα). An assay for the TFPIα synergistic cofactor activity of protein S with FV-Short was developed. The assay was specific for the synergistic TFPIα-cofactor activity of free protein S. Protein S deficient individuals with known mutations were correctly distinguished from controls. Summary: Background Protein S is an anticoagulant cofactor to both activated protein C and tissue factor pathway inhibitor (TFPIα). The TFPIα-cofactor activity of protein S is stimulated by a short isoform of factor V (FV-Short), the two proteins functioning in synergy. Objective Using the synergistic TFPIα-cofactor activity between protein S and FV-Short to... (More)

Essentials Protein S and FV-Short are synergistic cofactors to Tissue Factor Pathway Inhibitor α (TFPIα). An assay for the TFPIα synergistic cofactor activity of protein S with FV-Short was developed. The assay was specific for the synergistic TFPIα-cofactor activity of free protein S. Protein S deficient individuals with known mutations were correctly distinguished from controls. Summary: Background Protein S is an anticoagulant cofactor to both activated protein C and tissue factor pathway inhibitor (TFPIα). The TFPIα-cofactor activity of protein S is stimulated by a short isoform of factor V (FV-Short), the two proteins functioning in synergy. Objective Using the synergistic TFPIα-cofactor activity between protein S and FV-Short to develop a functional test for plasma protein S. Patients/Methods TFPIα-mediated inhibition of FXa in the presence of FV-Short, protein S and negatively charged phospholipid vesicles was monitored in time by synthetic substrate S2765. TFPIα, FXa and FV-Short were purified proteins, whereas diluted plasma from protein S deficient patients or controls were used as source for protein S. Results The assay was specific for free protein S demonstrating good correlation to free protein S plasma levels (r = 0.92) with a Y-axis intercept of −5%. Correlation to concentrations of total protein S (free and C4BPβ+-bound) was lower (r = 0.88) and the Y-axis intercept was +46%, which is consistent with the specificity for free protein S. The test distinguished protein S-deficient individuals from 6 families with known ProS1 mutations from family members having no mutation. Protein S levels of warfarin-treated protein S deficient cases were lower than protein S in cases treated with warfarin for other causes. Conclusions We describe a new assay measuring the TFPIα-cofactor activity of plasma protein S. The test identifies type I/III protein S deficiencies and will be a useful tool to detect type II protein S deficiency having defective TFPIα-cofactor activity.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
deep venous thrombosis, factor V, factor X, protein S, TFPI
in
Journal of Thrombosis and Haemostasis
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • scopus:85062797499
ISSN
1538-7933
DOI
10.1111/jth.14405
language
English
LU publication?
yes
id
3c83e146-7ab6-419f-aa3e-bdfe78d9b531
date added to LUP
2019-03-20 14:48:06
date last changed
2019-04-23 04:47:04
@article{3c83e146-7ab6-419f-aa3e-bdfe78d9b531,
  abstract     = {<p>Essentials Protein S and FV-Short are synergistic cofactors to Tissue Factor Pathway Inhibitor α (TFPIα). An assay for the TFPIα synergistic cofactor activity of protein S with FV-Short was developed. The assay was specific for the synergistic TFPIα-cofactor activity of free protein S. Protein S deficient individuals with known mutations were correctly distinguished from controls. Summary: Background Protein S is an anticoagulant cofactor to both activated protein C and tissue factor pathway inhibitor (TFPIα). The TFPIα-cofactor activity of protein S is stimulated by a short isoform of factor V (FV-Short), the two proteins functioning in synergy. Objective Using the synergistic TFPIα-cofactor activity between protein S and FV-Short to develop a functional test for plasma protein S. Patients/Methods TFPIα-mediated inhibition of FXa in the presence of FV-Short, protein S and negatively charged phospholipid vesicles was monitored in time by synthetic substrate S2765. TFPIα, FXa and FV-Short were purified proteins, whereas diluted plasma from protein S deficient patients or controls were used as source for protein S. Results The assay was specific for free protein S demonstrating good correlation to free protein S plasma levels (r = 0.92) with a Y-axis intercept of −5%. Correlation to concentrations of total protein S (free and C4BPβ+-bound) was lower (r = 0.88) and the Y-axis intercept was +46%, which is consistent with the specificity for free protein S. The test distinguished protein S-deficient individuals from 6 families with known ProS1 mutations from family members having no mutation. Protein S levels of warfarin-treated protein S deficient cases were lower than protein S in cases treated with warfarin for other causes. Conclusions We describe a new assay measuring the TFPIα-cofactor activity of plasma protein S. The test identifies type I/III protein S deficiencies and will be a useful tool to detect type II protein S deficiency having defective TFPIα-cofactor activity.</p>},
  author       = {Dahlbäck, Björn and Guo, Li Jun and Zöller, Bengt and Tran, Sinh},
  issn         = {1538-7933},
  keyword      = {deep venous thrombosis,factor V,factor X,protein S,TFPI},
  language     = {eng},
  month        = {02},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Journal of Thrombosis and Haemostasis},
  title        = {New functional test for the TFPIα cofactor activity of Protein S working in synergy with FV-Short},
  url          = {http://dx.doi.org/10.1111/jth.14405},
  year         = {2019},
}