Figure 4

Effect of tumour necrosis factor (TNF)-α and confluence on discontinuous adherens junction (AJ), stress fibres and focal adhesions. (A) Effect of TNF-α on actin filament, β-catenin and paxillin distribution. Confluent human umbilical vein endothelial cells (HUVECs) were starved for 4 h and then, as indicated, stimulated with 10 ng/ml TNF-α for 20 h. In parallel, subconfluent HUVECs were also starved and stimulated with TNF-α. Cells were fixed and distribution of F-actin, β-catenin and paxillin was analyzed by immunofluorescence. Bottom panels show the red boxed areas indicated in merged images at higher magnification. (B) Distribution of F-actin, VE-cadherin and phospho-Y(118)-paxillin in TNF-α-stimulated confluent HUVECs. Arrowheads indicate discontinuous AJ, whereas arrows indicate focal adhesions detected by phospho-paxillin staining.