Expression of the UGA4 gene encoding the delta-aminolevulinic and gamma-aminobutyric acids permease in Saccharomyces cerevisiae is controlled by amino acid-sensing systems.

In yeasts, several sensing systems localized to the plasma membrane which transduce information regarding the availability and quality of nitrogen and carbon sources and work in parallel with the intracellular nutrient-sensing systems, regulate the expression and activity of proteins involved in nutrient uptake and utilization. The aim of this work was to establish whether the cellular signals triggered by amino acids modify the expression of the UGA4 gene which encodes the delta-aminolevulinic (ALA) and gamma-aminobutyric (GABA) acids permease. In the present paper, we demonstrate that extracellular amino acids regulate UGA4 expression and that this effect seems to be mediated by the amino acid sensor complex SPS (SSY1, PTR3, SSY5).