Figure 5. Effect of ATP on transepithelial electrical properties of fhRPE monolayers. Representative recordings from monolayers expressing endogenous hBest1 (control) or overexpressing hBest1 or hBest1^W93C (W93C) in response to a 50 µM ATP stimulus are shown in A. TEP (B) increased in controls and cells expressing hBest1^W93C in response to ATP, but diminished significantly in cells overexpressing hBest1. Vertical bars in the recordings in A correspond to the voltage deflection induced by a 10 µA bipolar current pulse used to determine TER (C), which diminished precipitously in monolayers overexpressing hBest1. I_sc (D) was calculated from TEP and TER. Data are representative of ≥4 experiments.