title: Identification of the fnx1+ and fnx2+ genes for vacuolar amino acid transporters in Schizosaccharomyces pombe.
abstract: We have identified the Schizosaccharomyces pombe SPBC3E7.06c gene (fnx2(+)) from a homology search with the fnx1(+) gene involving in G(0) arrest upon nitrogen starvation. Green fluorescent protein-fused Fnx1p and Fnx2p localized exclusively to the vacuolar membrane. Uptake of histidine or isoleucine by S. pombe cells was inhibited by concanamycin A, a specific inhibitor of the vacuolar H(+)-ATPase. Amino acid uptake was also defective in the vacuolar ATPase mutant, suggesting that vacuolar compartmentalization is critical for amino acid uptake by whole cells. In both Deltafnx1 and Deltafnx2 mutant cells, uptake of lysine, isoleucine or asparagine was impaired. These results suggest that fnx1(+) and fnx2(+) are involved in vacuolar amino acid uptake in S. pombe.
authors.affiliation: Faculty of Agriculture, Ehime University, Ehime 790-8566, Japan.
authors.forename: Soracom
authors.initials: S
authors.lastname: Chardwiriyapreecha
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Shimazu
authors.forename: Tomotake
authors.initials: T
authors.lastname: Morita
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sekito
authors.forename: Koichi
authors.initials: K
authors.lastname: Akiyama
authors.forename: Kaoru
authors.initials: K
authors.lastname: Takegawa
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Kakinuma
mesh_terms: D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D001692:Biological Transport; D007425:Intracellular Membranes / Q000201:enzymology*; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D012568:Schizosaccharomyces / Q000201:enzymology* / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology*
chemical_list: D026905:Amino Acid Transport Systems; D000596:Amino Acids; C114071:FNX1 protein, S pombe; C530830:FNX2 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins