Activity-dependent reversible inactivation of the general amino acid permease

April L. Risinger, Natalie E. Cain, Esther J. Chen, Chris A. Kaiser

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


The general amino acid permease, Gap1p, of Saccharomyces cerevisiae transports all naturally occurring amino acids into yeast cells for use as a nitrogen source. Previous studies have shown that a nonubiquitinateable form of the permease, Gap1pK9R,K16R, is constitutively localized to the plasma membrane. Here, we report that amino acid transport activity of Gap1pK9R,K16R can be rapidly and reversibly inactivated at the plasma membrane by the presence of amino acid mixtures. Surprisingly, we also find that addition of most single amino acids is lethal to Gap1pK9R,K16R- expressing cells, whereas mixtures of amino acids are less toxic. This toxicity appears to be the consequence of uptake of unusually large quantities of a single amino acid. Exploiting this toxicity, we isolated gap1 alleles deficient in transport of a subset of amino acids. Using these mutations, we show that Gap1p inactivation at the plasma membrane does not depend on the presence of either extracellular or intracellular amino acids, but does require active amino acid transport by Gap1p. Together, our findings uncover a new mechanism for inhibition of permease activity in response to elevated amino acid levels and provide a physiological explanation for the stringent regulation of Gap1p activity in response to amino acids.

Original languageEnglish (US)
Pages (from-to)4411-4419
Number of pages9
JournalMolecular Biology of the Cell
Issue number10
StatePublished - Oct 2006
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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