siRNA-mediated depletion of αSNAP prevents formation of the paracellular barrier and AJ/TJ assembly, and selectively downregulates p120 catenin and E-cadherin expression.

<p>(<b>A</b>) Immunoblotting analysis shows that two different αSNAP-specific siRNA duplexes (D1 & D2) dramatically decrease its protein expression in SK-CO15 cells on day 3 post-transfection. (<b>B</b>) TEER measurements demonstrate that αSNAP-depleted SK-CO15 cell monolayers fail to develop the paracellular barrier. (<b>C</b>) Immunofluorescence labeling shows formation of normal β-catenin-based AJs and occludin-based TJs (arrows) in control SK-CO15 cell monolayers on day 4 post-transfection. By contrast, αSNAP-depleted cells have significant intracellular accumulation of β-catenin and fragmented TJ strands (arrowheads). (<b>D</b>) Immunoblotting analysis shows that selective αSNAP depletion increases the level of TJ proteins but dramatically downregulates p120 catenin and E-cadherin expression in SK-CO15 cells on day 4 post-transfection; *p<0.05, ^#p<0.01 compared to the control siRNA-treated group (n = 3). Scale bar, 20 µM.