title: Vacuolar transporter Avt4 is involved in excretion of basic amino acids from the vacuoles of Saccharomyces cerevisiae.
abstract: Basic amino acids (lysine, histidine and arginine) accumulated in Saccharomyces cerevisiae vacuoles should be mobilized to cytosolic nitrogen metabolism under starvation. We found that the decrease of vacuolar basic amino acids in response to nitrogen starvation was impaired by the deletion of AVT4 gene encoding a vacuolar transporter. In addition, overexpression of AVT4 reduced the accumulation of basic amino acids in vacuoles under nutrient-rich condition. In contrast to AVT4, the deletion and overexpression of AVT3, which encodes the closest homologue of Avt4p, did not affect the contents of vacuolar basic amino acids. Consistent with these, arginine uptake into vacuolar membrane vesicles was decreased by Avt4p-, but not by Avt3p-overproduction, whereas various neutral amino acids were excreted from vacuolar membrane vesicles in a manner dependent on either Avt4p or Avt3p. These results suggest that Avt4p is a vacuolar amino acid exporter involving in the recycling of basic amino acids.
authors.affiliation: a Laboratory of Molecular Physiology and Genetics, Faculty of Agriculture , Ehime University , Matsuyama , Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sekito
authors.forename: Soracom
authors.initials: S
authors.lastname: Chardwiriyapreecha
authors.forename: Naoko
authors.initials: N
authors.lastname: Sugimoto
authors.forename: Masaya
authors.initials: M
authors.lastname: Ishimoto
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kawano-Kawada
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Kakinuma
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D026923:Amino Acid Transport Systems, Basic / Q000737:chemistry / Q000378:metabolism*; D024361:Amino Acids, Basic / Q000378:metabolism*; D001692:Biological Transport; D007425:Intracellular Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D026923:Amino Acid Transport Systems, Basic; D024361:Amino Acids, Basic; C000595992:Avt4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000255:Adenosine Triphosphate
keywords: Saccharomyces cerevisiae; amino acid transporter; vacuole