title: phoU inactivation in Pseudomonas aeruginosa enhances accumulation of ppGpp and polyphosphate.
abstract: Inorganic polyphosphate (polyP) is a linear polymer composed of several molecules of orthophosphate (Pi) linked by energy-rich phosphoanhydride bonds. In Pseudomonas aeruginosa, Pi is taken up by the ABC transporter Pst, encoded by an operon consisting of five genes. The first four genes encode proteins involved in the transport of Pi and the last gene of the operon, phoU, codes for a protein which exact function is unknown. We show here that the inactivation of phoU in P. aeruginosa enhanced Pi removal from the medium and polyP accumulation. The phoU mutant also accumulated high levels of the alarmone guanosine tetraphosphate (ppGpp), which in turn increased the buildup of polyP. In addition, phoU inactivation had several pleiotropic effects, such as reduced growth rate and yield and increased sensitivity to antibiotics and stresses. However, biofilm formation was not affected by the phoU mutation.
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Luiz Gustavo
authors.initials: LG
authors.lastname: de Almeida
authors.affiliation: Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Julia Helena
authors.initials: JH
authors.lastname: Ortiz
authors.affiliation: Departamento de Engenharia Química, Escola Politécnica, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: René P
authors.initials: RP
authors.lastname: Schneider
authors.affiliation: Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil benys@usp.br.
authors.forename: Beny
authors.initials: B
authors.lastname: Spira
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D055786:Gene Knockout Techniques; D006159:Guanosine Tetraphosphate / Q000378:metabolism*; D009876:Operon; D011122:Polyphosphates / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011122:Polyphosphates; D006159:Guanosine Tetraphosphate