FIGURE 2.

VPA does not cause a vma⁻ phenotype. A, wild-type (WT) BY4741 and isogenic vma3Δ, vph1Δ, and stv1Δ mutant cells were precultured in SM I+, washed twice to remove inositol, and spotted in a 10-fold dilution series on SM in the presence or absence of 75 μm inositol and 2 mm VPA. Media were buffered to either pH 5.5 or 7.5. CaCl₂ (100 mm) was added to unbuffered medium. Cells were grown for 3–4 days at 30 °C. B, inositol rescues VPA sensitivity of V-ATPase V₀ deletion mutants. Wild-type (WT) BY4741 and isogenic vmaΔ mutant cells were precultured in SM I+, washed twice to remove inositol, and spotted in a 10-fold dilution series on SM in the presence or absence of 75 μm inositol and 2 mm VPA. Cells were grown for 3–4 days at 30 °C. The experiments were done twice in duplicate.