title: Possible involvement of protein phosphatase type 2A in tumor necrosis factor alpha-induced tissue factor expression in endothelial cells.
abstract: The involvement of protein Ser/Thr phosphatase types 2A (PP2A) and 1 (PP1) in tumor necrosis factor alpha (TNF alpha)-induced tissue factor (TF) expression of human umbilical vein endothelial cells (HUVEC) was investigated. PP2A was more abundant than PP1 in the cytosol of HUVEC. CAL-A (0.5 nM) and OKA (2 nM), cell permeable inhibitors of PP1 and PP2A, augmented TNF alpha-induced TF expression, although TF expression induced by either TPA or thrombin was unchanged in the presence of GAL-A. Addition of CAL-A (0.5 nM) to TNF alpha-stimulated cultures led to an increase in the accumulation of TF transcripts. CAL-A (0.5 nM) also augmented the TNF alpha-induced phosphorylation of I kappa B-alpha, an inhibitor of NF-kappa B. Since PP2A is more sensitive to OKA than PP1, these results suggest that PP2A may be involved in regulating TNF alpha-induced TF expression in HUVEC through I kappa B-alpha dephosphorylation.
authors.affiliation: MIE UNIV,SCH MED,DEPT INTERNAL MED 2,TSU,MIE 514,JAPAN.
authors.forename: S
authors.initials: S
authors.lastname: Nagaya
authors.forename: K
authors.initials: K
authors.lastname: Nakai
authors.forename: M
authors.initials: M
authors.lastname: Shimura
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Shiku
authors.forename: M
authors.initials: M
authors.lastname: Nishikawa