Fig. 4.

Cigarette smoke extract and PP2A inhibition alter endothelial cell permeability and occluding phosphorylation. (A) FITC permeability assays were conducted on human microvascular endothelial cells monolayers grown to 100% confluence on 3-µm pore collagen-coated PTFE membranes that were treated with 5% CSE for 2, 4, 6, 18 and 24 h. (B) FITC permeability assays were conducted on human microvascular endothelial cell monolayers grown to 100% confluence on 3-µm pore collagen-coated PTFE membranes that were treated with 1-µM Fostriecin for 24 h. (C) Occludin protein was immunoprecipitated from the endothelial cell lysates using a specific antibody. Immunoblots for p-threonine and total occludin were conducted on the immunoprecipitated protein.