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Filamin-A is required for the incorporation of tissue factor into cell-derived microvesicles

Authors :
Mary E. W. Collier
Camille Ettelaie
Anthony Maraveyas
Source :
Thrombosis and Haemostasis. 111:647-655
Publication Year :
2014
Publisher :
Georg Thieme Verlag KG, 2014.

Abstract

SummaryWe previously reported that the incorporation of tissue factor (TF) into cell-derived microvesicles (MVs) is regulated by the phosphorylation of the cytoplasmic domain of TF. Since the cytoskeletal protein filamin-A is known to bind to the cytoplasmic domain of TF in a phosphorylation-dependent manner, the involvement of filamin-A in the incorporation of TF into MVs was examined. Endothelial cells were transfected to express TF, whereas MDA-MB-231 cells were used to examine endogenously expressed TF. MV release was induced by activating protease-activated receptor-2 (PAR2). Partial suppression of filamin-A expression using two different filamin-A siRNA sequences resulted in significant reductions in the incorporation of TF antigen into MVs as determined by TF-ELISA and western blot analysis, and was reflected in reduced thrombin-generation and FXa-generation capacities of these MVs. Deletion of the cytoplasmic domain of TF also resulted in reduced incorporation of TF into MVs, whereas the suppression of filamin-A expression had no additional effect on the incorporation of truncated TF into MVs. Partial suppression of filamin-A expression had no effect on the number and size distribution of the released MVs. However, >90% suppression of filamin-A expression resulted in increased MV release, possibly as a result of increased instability of the plasma membrane and underlying cytoskeleton. In conclusion, the presence of filamin-A appears to be essential for the incorporation of TF into MVs following PAR2 activation, but is not required for the process of MV formation and release following PAR2 activation.

Details

ISSN :
2567689X and 03406245
Volume :
111
Database :
OpenAIRE
Journal :
Thrombosis and Haemostasis
Accession number :
edsair.doi.dedup.....8eacb0fc3db595a080cc1044a66f56f7