Document Detail


Activity-dependent reversible inactivation of the general amino acid permease.
MedLine Citation:
PMID:  16885415     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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, Gap1p(K9R,K16R), is constitutively localized to the plasma membrane. Here, we report that amino acid transport activity of Gap1p(K9R,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 Gap1p(K9R,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.
Authors:
April L Risinger; Natalie E Cain; Esther J Chen; Chris A Kaiser
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2006-08-02
Journal Detail:
Title:  Molecular biology of the cell     Volume:  17     ISSN:  1059-1524     ISO Abbreviation:  Mol. Biol. Cell     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-25     Completed Date:  2007-01-26     Revised Date:  2010-09-15    
Medline Journal Info:
Nlm Unique ID:  9201390     Medline TA:  Mol Biol Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4411-9     Citation Subset:  IM    
Affiliation:
Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Transport Systems / metabolism*
Amino Acids / pharmacokinetics*,  toxicity
Cell Membrane / enzymology
Enzyme Activation
Enzyme Inhibitors / pharmacology
Gene Expression Regulation, Fungal*
Protein Transport / drug effects
Saccharomyces cerevisiae / enzymology*,  growth & development
Saccharomyces cerevisiae Proteins / metabolism*
Grant Support
ID/Acronym/Agency:
GM56933/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Amino Acid Transport Systems; 0/Amino Acids; 0/Enzyme Inhibitors; 0/GAP1 protein, S cerevisiae; 0/Saccharomyces cerevisiae Proteins
Comments/Corrections

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