SK regulates PECAM-1 expression and phosphorylation levels. (A) Flow cytometry profile of the cell surface expression of PECAM-1 in ECs^EV (open curve) and ECs^SK (shaded curve) analyzed 48 hours after infection. MFI indicates mean fluorescent intensity. (B) Western blot for PECAM-1 and β-catenin expression in these cells. (C) Cell surface expression of PECAM (▦) and VE-cadherin (VE Cadh; □), as indicated by the median fluorescence intensity, in ECs^SK and ECs^EV. The figure shows the pooled data from 3 separate experiments normalized to EV = 1. *P less than .001 for ECs^SK compared with ECs^EV. Bars represent 95% confidence intervals. (D) PECAM-1 phosphorylation (top) as detected by an antiphosphotyrosine antibody and total PECAM-1 (bottom) in ECs. (E) Flow cytometry profile of cell surface expression of PECAM-1 on ECs^EV (open curve) and ECs^SK (shaded curve) analyzed 96 hours after infection including 48 hours of growth in SF conditions.