Physiological regulation of the derepressible phosphate transporter in Saccharomyces cerevisiae.

The extracellular phosphate concentration permissive for the expression of different amounts of the active high-affinity Pho84 phosphate transporter in the plasma membrane as well as the PHO84 messenger RNA levels in low-phosphate-grown Saccharomyces cerevisiae cells is very narrow and essential for a tight regulation of the transporter. The Pho84 transporter undergoes a rapid degradation once the supply of phosphate and/or carbon source is exhausted.