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Regulation of chemotaxis by the cytoplasmic domain of tissue factor

Journal: Thrombosis and Haemostasis
ISSN: 0340-6245
DOI: http://dx.doi.org/10.1160/TH04-07-0405
Issue: 2005: 93/1 (Jan) pp. 1-185
Pages: 27-34

Regulation of chemotaxis by the cytoplasmic domain of tissue factor

Agneta Siegbahn, Matilda Johnell, Brit B. Sorensen, Lars C. Petersen, Carl-Henrik Heldin
Department of Medical Sciences, Clinical Chemistry, Akademiska Hospital and Ludwig Institute for Cancer Research, Biomedical Centre, Uppsala Sweden, Haemostasis Biology, Health Care Discovery, Novo Nordisk A/S, Maaloev, Denmark

Summary

We previously demonstrated that FVIIa bound to tissue factor (TF) induces a hyperchemotactic response towards PDGF-BB. The aim of the present study was to investigate the role of the cytoplasmic domain of TF in cell migration. Porcine aortic endothelial (PAE) cells expressing human PDGF β-receptors (PAE/ PDGFR β) were transfected for expression of human wildtype TF (PAE/PDGFRβ,TF), a construct lacking the cytoplasmic domain (PAE/PDGFRβ,TFΔ cyto), a construct with alanine replacement of serine 258 (PAE/PDGFRβ,TFS258A), or a construct with alanine replacement of serine 253, 258 and 263 in the cytoplasmic domain (PAE/PDGFRβ,TF3SA). All stably transfected cell lines expressed functional TF. Chemotaxis was analyzed in a modified Boyden chamber assay. PAE/PDGFRβ,TF cells stimulated with FVIIa migrated towards a 100-fold lower concentration of PDGF-BB than in the absence of FVIIa,however,hyperchemotaxis was not seen in PAE/PDGFRβ,TFΔ cyto cells. PAE/ PDGFRβ/TFS258A and PAE/PDGFRβ,TF3SA cells responded to low levels of PDGF-BB, but migrated a significantly shorter distance than PAE/PDGFRβ,TF cells. Thus, hyperchemotaxis towards PDGF-BB is likely to depend in part on phosphorylation of the cytoplasmic domain of TF.We conclude that the cytoplasmic domain of TF plays a pivotal role in modulating cellular migration response.Our results suggest that the FVIIa/TF complex mediates intracellular signaling by alternative signal transduction pathway(s).