Activation of yeast plasma membrane ATPase by phorbol ester.

Addition of 12-O-tetradecanoylphorbol-13-acetate (TPA) to yeast cells produces a 2-fold activation of the plasma membrane ATPase. The activation is reversible and time-and dose-dependent. The activated enzyme shows an increased affinity for its substrate, ATP, and its optimum pH is shifted to a more alkaline range. These changes are similar to those observed in the reported activation by glucose. Upon incubation of yeast cells with 32Pi incorporation of radioactivity in a membrane polypeptide of 105 kDa is observed after addition of either glucose or TPA.