VIIa/tissue factor interaction results in a tissue factor cytoplasmic domain-independent activation of protein synthesis, p70, and p90 S6 kinase phosphorylation.
FVIIa binding to tissue factor (TF) and subsequent signal transduction have now been implicated in a variety of pathophysiological processes, including cytokine production during sepsis, tumor angiogenesis and neoangiogenesis, and leukocyte diapedesis. The molecular details, however, by which FVIIa/TF affects gene expression and cellular physiology, remain obscure. Here we show that FVIIa induces a transient phosphorylation of p70/p85(S6K) and p90(RSK) in BHK cells stably transfected with either full-length TF or with a cytoplasmic domain-truncated TF but not in wild type BHK cells. Phosphorylation of these kinases was also observed in HaCaT cells, expressing endogenous TF. Phosphorylation of p70/p85(S6K) coincided with protein kinase B and GSK-3beta phosphorylation. Activation of p70/p85(S6K) was sensitive to inhibitors of phosphatidylinositol 3-kinase and to rapamycin, whereas phosphorylation of p90(RSK) was sensitive to PD98059. FVIIa stimulation of p70/p85(S6K) and p90(RSK) correlated with phosphorylation of the eukaryotic initiation factor eIF-4E, up-regulation of protein levels of eEF1alpha and eEF2, and enhanced [(35)S]methionine incorporation. These effects were not influenced by inhibitors of thrombin or FXa generation and were strictly dependent on the presence of the extracellular domain of TF, but they did not require the intracellular portion of TF. We propose that a TF cytoplasmic domain-independent stimulation of protein synthesis via activation of S6 kinase contributes to FVIIa effects in pathophysiology.
Versteeg
Henri H
HH
Laboratory for Experimental Internal Medicine and the Department of Oncology, Academic Medical Center, Meibergdreef 9, AZ Amsterdam NL-1105, The Netherlands.
Sørensen
Brit B
BB
Slofstra
Sjoukje H
SH
Van den Brande
Jan H M
JH
Stam
Jord C
JC
van Bergen en Henegouwen
Paul M P
PM
Richel
Dick J
DJ
Petersen
Lars C
LC
Peppelenbosch
Maikel P
MP
D000818:Animals; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D006224:Cricetinae; D003593:Cytoplasm / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D039561:Eukaryotic Initiation Factor-4E; D015942:Factor VIIa / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3; D006801:Humans; D010448:Peptide Initiation Factors / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism; D013925:Thromboplastin / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
D004791:Enzyme Inhibitors; D039561:Eukaryotic Initiation Factor-4E; D005419:Flavonoids; D010448:Peptide Initiation Factors; D011506:Proteins; D011518:Proto-Oncogene Proteins; D013925:Thromboplastin; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019893:Ribosomal Protein S6 Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D015942:Factor VIIa; D013917:Thrombin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D020123:Sirolimus