Protein kinase A activity was reduced in the ΔshoA, ΔmsbA, ΔopyA, and double null mutants. The strains were grown for 24 or 48 h in MM plus 1% glucose. The results shown represent the means of measurements of three independent repetitions ± standard deviation. The data were analyzed (Prism, GraphPad) using two-way ANOVA followed by Bonferroni posttests. The levels of significance compared to the wild-type results are indicated as follows: *, P < 0.1; **, P < 0.01; ***, P < 0.001.