Figure 7.

TER recovery after calcium switch is impaired after Rap1 knockdown or expression of RapGAP. ARPE-19 cells grown on Transwell filters were infected with adenovirus to express negative control RNAi, Rap1 RNAi, or RapGAP protein. Initial (t = 0) TER measurements were taken 48 hours post virus addition. Cells were then treated with EGTA for 30 minutes to disrupt cell-cell junctions, followed by washout and readdition of calcium-containing media for the indicated times to allow for junctional reassembly. The graph shows the average change in TER (ohms per cm²), relative to control cells at t = 0. Data points are the average ± SD from n = 4 wells (*P < 0.02, comparing both Rap1-knockdown and RapGAP-expressing cells to control). Shown is one representative from three independently performed experiments.