title: The biochemical characterization of two phosphate transport systems in Phytomonas serpens.
abstract: Inorganic phosphate (Pi) is an essential nutrient for all organisms because it is required for a variety of biochemical processes, such as signal transduction and the synthesis of phosphate-containing biomolecules. Assays of32Piuptake performed in the absence or in the presence of Na+indicated the existence of a Na+-dependent and a Na+-independent Pitransporter in Phytomonas serpens. Phylogenetic analysis of two hypothetical protein sequences of Phytomonas (EM1) showed similarities to the high-affinity Pitransporters of Saccharomyces cerevisiae: Pho84, a Na+-independent Pitransporter, and Pho89, a Na+-dependent Pitransporter. Plasma membrane depolarization by FCCP, an H+ionophore, strongly decreased Piuptake via both Na+-independent and Na+-dependent carriers, indicating that a membrane potential is essential for Piinflux. In addition, the furosemide-sensitive Na+-pump activity in the cells grown in low Piconditions was found to be higher than the activity detected in the plasma membrane of cells cultivated at high Piconcentration, suggesting that the up-regulation of the Na+-ATPase pump could be related to the increase of Piuptake by the Pho89p Na+:Pisymporter. Here we characterize for the first time two inorganic phosphate transporters powered by Na+and H+gradients and activated by low Piavailability in the phytopathogen P. serpens.
authors.affiliation: Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Vieira-Bernardo
authors.affiliation: Instituto de Ciências Exatas, Departamento de Química, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brazil.
authors.forename: André Luiz
authors.initials: AL
authors.lastname: Gomes-Vieira
authors.affiliation: Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Carvalho-Kelly
authors.affiliation: Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil.
authors.forename: Thais
authors.initials: T
authors.lastname: Russo-Abrahão
authors.affiliation: Laboratório de Bioquímica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ, Brazil. Electronic address: meyer@bioqmed.ufrj.br.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D017136:Ion Transport; D007700:Kinetics; D008564:Membrane Potentials; D010710:Phosphates / Q000378:metabolism*; D028081:Proton-Phosphate Symporters / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D050608:Sodium-Phosphate Cotransporter Proteins / Q000235:genetics / Q000378:metabolism*; D014351:Trypanosomatina / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D027682:Cation Transport Proteins; D010710:Phosphates; D028081:Proton-Phosphate Symporters; D012333:RNA, Messenger; D016053:RNA, Protozoan; D050608:Sodium-Phosphate Cotransporter Proteins; D006859:Hydrogen; D012964:Sodium; D000251:Adenosine Triphosphatases; C021838:sodium-translocating ATPase
keywords: H(+)-dependent phosphate transport; Na(+)-dependent phosphate transport; Phytomonas serpens