TRANSCRIPTIONAL REGULATION BY GLUCOSE OF THE YEAST PMA1 GENE ENCODING THE PLASMA-MEMBRANE H+-ATPASE

The yeast plasma membrane H+-ATPase generates a membrane electrochemical gradient which is required for the secondary uptake of nutrients. Although the ATPase has previously been shown to be post-translationally regulated in response to the availability of glucose, there has been no evidence to date for transcriptional regulation of the ATPase gene (PMA1). In this work, we have examined the pool of newly synthesized ATPase that accumulates in secretory vesicles en route to the cell surface in the temperature-sensitive secretory mutant sec6-4, and have observed changes in the level of ATPase polypeptide as a function of the glucose concentration in the growth medium. In parallel, there were rapid and reversible changes in the levels of ATPase mRNA. Finally, when cells were grown on a variety of carbon sources, the amount of ATPase polypeptide was proportional to the specific growth rate, suggesting that PMA1 expression is adjusted according to the metabolic state of the cell. These results complement the findings of Capieaux et al. (Capieaux, E., Vignais, M.-L., Sentenac, A. and Goffeau, A. (1989). J. Biol. Chem. 264, 7437-7446), who show that the transcriptional factor TUF/RAP1 binds to upstream activating sequences in the PMA1 gene. Taken together, the results suggest a model in which transcriptional regulation of the ATPase gene by glucose is mediated by TUF/RAP1.