67 research outputs found
Phosphate Starvation Triggers Production and Secretion of an Extracellular Lipoprotein in Caulobacter crescentus
Life in oligotrophic environments necessitates quick adaptive responses to a sudden lack of nutrients. Secretion of specific degradative enzymes into the extracellular medium is a means to mobilize the required nutrient from nearby sources. The aquatic bacterium Caulobacter crescentus must often face changes in its environment such as phosphate limitation. Evidence reported in this paper indicates that under phosphate starvation, C. crescentus produces a membrane surface-anchored lipoprotein named ElpS subsequently released into the extracellular medium. A complete set of 12 genes encoding a type II secretion system (T2SS) is located adjacent to the elpS locus in the C. crescentus genome. Deletion of this T2SS impairs release of ElpS in the environment, which surprisingly remains present at the cell surface, indicating that the T2SS is not involved in the translocation of ElpS to the outer membrane but rather in its release. Accordingly, treatment with protease inhibitors prevents release of ElpS in the extracellular medium suggesting that ElpS secretion relies on a T2SS-secreted protease. Finally, secretion of ElpS is associated with an increase in alkaline phosphatase activity in culture supernatants, suggesting a role of the secreted protein in inorganic phosphate mobilization. In conlusion, we have shown that upon phosphate starvation, C. crescentus produces an outer membrane bound lipoprotein, ElpS, which is further cleaved and released in the extracellular medium in a T2SS-dependent manner. Our data suggest that ElpS is associated with an alkaline phosphatase activity, thereby allowing the bacterium to gather inorganic phosphates from a poor environment
Characterization and cytotoxic effect of aqua-(2,2′,2′′-nitrilotriacetato)-oxo-vanadium salts on human osteosarcoma cells
Vanadium pentoxide effects on stress responses in wine Saccharomyces cerevisiae strain UE-ME3
Effects of oxotungstates and oxomolybdates on growth of S-cerevisiae.
Crans DC, Rosu C, Müller A, Willsky GR, Nomiya K. Effects of oxotungstates and oxomolybdates on growth of S-cerevisiae. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY. 2002;223:229-INOR
Are the Multiple Signal Transduction Pathways of the Pho Regulon Due to Cross Talk or Cross Regulation?
Cloning and characterization of the alkaline phosphatase positive regulator gene (phoB) of Escherichia coli
Production of extracellular alkaline phosphatase by Escherichia coli K-12 periplasmic-leaky mutants carrying phoA + Plasmids
- …