Expression of the V656L and V656A mutants is similar to that of the WT. PM vesicles were solubilized in SDS-PAGE sample buffer at 37°C for 30 min. We used 10 μg of protein to produce the Western blot. Each is a representative example from three independent experiments. Lane 1, WT; lane 2, Δpdr5 strain; lane 3, V656A mutant; lane 4, V656L mutant. Values are the ratios of the Pdr5 signal to the Pma1 signal, computed from Image J software as described in the experimental procedures.