Fig. 6. Effect of VX-809 on the surface expression of the mutants. Treatment with VX-809 produced an increase in protein expression at the cell surface (A). Ezrin was used as an internal control. Note that ezrin is an intracellular protein, and the failure to detect any ezrin in the biotinylated fraction demonstrates convincingly that the plasma membrane was intact during the biotinylation experiment. The surface protein expression of ABCA4 and the mutants A1038V and G1961E are significantly increased after treatment with VX809. (B) total lysate values are shown for comparison.