title: A novel alkali-tolerant Yarrowia lipolytica strain for dissecting Na+-coupled phosphate transport systems in yeasts.
abstract: The newly isolated osmo-, salt- and alkali-tolerant Yarrowia lipolytica yeast strain is remarkable by its capacity to grow at alkaline pH values (pH 9.7), which makes it an excellent model system for studying Na(+)-coupled phosphate transport systems in yeast cells grown at alkaline conditions. In cells Y. lipolytica grown at pH 9.7, phosphate uptake was mediated by several kinetically discrete Na(+)-dependent systems that are specifically activated by Na(+) ions. One of these, a low-affinity transporter, operated at high-phosphate concentrations. The other two, derepressible, high-affinity, high-capacity systems, functioned during phosphate starvation. Both H(+)- and Na(+)-coupled high-affinity phosphate transport systems of Y. lipolytica cells were under the dual control of the prevailing extracellular phosphate concentrations and pH values. The contribution of the Na(+)/P(i)-cotransport systems into the total cellular phosphate uptake activity was progressively increased with increasing pH, reaching its maximum at pH > or = 9.
authors.affiliation: Laboratory of Biological Oxidation, AN Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia. renata_z@inbi.ras.ru
authors.forename: Renata
authors.initials: R
authors.lastname: Zvyagilskaya
authors.forename: Bengt L
authors.initials: BL
authors.lastname: Persson
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010710:Phosphates / Q000378:metabolism*; D012964:Sodium / Q000502:physiology*; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters / Q000502:physiology; D025062:Yarrowia / Q000187:drug effects / Q000502:physiology*
chemical_list: D000468:Alkalies; D010710:Phosphates; D050608:Sodium-Phosphate Cotransporter Proteins; D027981:Symporters; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D012964:Sodium