Activation of yeast plasma membrane ATPase by phorbol ester

Abstract
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.