title: Polyamine uptake by DUR3 and SAM3 in Saccharomyces cerevisiae.
abstract: It has been reported that GAP1 and AGP2 catalyze the uptake of polyamines together with amino acids in Saccharomyces cerevisiae. We have looked for polyamine-preferential uptake proteins in S. cerevisiae. DUR3 catalyzed the uptake of polyamines together with urea, and SAM3 was found to catalyze the uptake of polyamines together with S-adenosylmethionine, glutamic acid, and lysine. Polyamine uptake was greatly decreased in both DUR3- and SAM3-deficient cells. The K(m) values for putrescine and spermidine of DUR3 were 479 and 21.2 mum, respectively, and those of SAM3 were 433 and 20.7 mum, respectively. Polyamine stimulation of cell growth of a polyamine requiring mutant, which is deficient in ornithine decarboxylase, was not influenced by the disruption of GAP1 and AGP2, but it was diminished by the disruption of DUR3 and SAM3. Furthermore, the polyamine stimulation of cell growth of a polyamine-requiring mutant was completely inhibited by the disruption of both DUR3 and SAM3. The results indicate that DUR3 and SAM3 are major polyamine uptake proteins in yeast. We previously reported that polyamine transport protein kinase 2 regulates polyamine transport. It was found that DUR3 (but not SAM3) was activated by phosphorylation of Thr(250), Ser(251), and Thr(684) by polyamine transport protein kinase 2.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uemura
authors.forename: Keiko
authors.initials: K
authors.lastname: Kashiwagi
authors.forename: Kazuei
authors.initials: K
authors.lastname: Igarashi
mesh_terms: D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems / Q000235:genetics / Q000502:physiology*; D015317:Biogenic Polyamines / Q000378:metabolism*; D001692:Biological Transport; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D026905:Amino Acid Transport Systems; D015317:Biogenic Polyamines; C515373:DUR3 protein, S cerevisiae; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C429746:SAM3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins