Yeast Agp2p and Agp3p function as amino acid permeases in poor nutrient conditions

Biochem Biophys Res Commun. 2004 Jan 16;313(3):745-51. doi: 10.1016/j.bbrc.2003.11.172.


The gene AGP2 and the ORF YFL055w (here named AGP3) are classified as members of the yeast amino acid permease gene family. Analysis of the growth of multiply-mutant strains in which these genes are disrupted shows that both encode permeases capable of supplying branched chain, and other, amino acids as nitrogen source. Both Agp2p and Agp3p are low affinity permeases for leucine (Kmapp 0.2-0.5 mM) and are expressed at lower levels than other permeases on all media tested. Thus, it appears that these two permeases can function as low affinity, relatively non-specific, permeases with redundant functions in the cell. Transcription of AGP2 and AGP3 is very low but is increased in cells lacking other functional general amino acid permeases (Gap1p or Agp1p). These results suggest Agp2p and Agp3p function in amino acid transport when nitrogen sources are limiting and/or other permeases are inactive.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Transport Systems / chemistry
  • Amino Acid Transport Systems / physiology*
  • Biological Transport
  • Cell Membrane / metabolism
  • Cloning, Molecular
  • Culture Media / pharmacology
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Fungal
  • Genotype
  • Kinetics
  • Leucine / pharmacokinetics
  • Membrane Transport Proteins / chemistry
  • Nitrogen / metabolism
  • Open Reading Frames
  • Plasmids / metabolism
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology*
  • Symporters / physiology*
  • Transcription, Genetic


  • Agp2 protein, S cerevisiae
  • Agp3 protein, S cerevisiae
  • Amino Acid Transport Systems
  • Culture Media
  • Membrane Transport Proteins
  • Saccharomyces cerevisiae Proteins
  • Symporters
  • Leucine
  • Nitrogen