FIG. 5.
Flow-cytometric analysis of β-integrin expression and activity in ILK-deficient endothelial cells. ILKflox/flox endothelial cells were either left uninfected (U) or transduced with AdGFP or AdCre. Flow-cytometric analysis was performed by using an antibody specific for the active conformation of β1 integrins before (A) and after (B) manganese stimulation (Mn, 2 mM, 5 min, 37°C). We observed a 26% decrease in mean fluorescence intensity (MFI) in AdCre-transduced, as opposed to uninfected or AdGFP-transduced, endothelial cells. Addition of Mn enhanced β1-integrin activation by 39% in uninfected endothelial cells, 49% in AdGFP-transduced endothelial cells, and 72% in AdCre-transduced endothelial cells. Surface expression of total β1 and β3 integrins as determined by flow cytometric analysis was unchanged (C and D, respectively). Analysis was limited to the viable cell population as determined by propidium iodide staining. Representative data from one of five independent experiments are shown.