Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa

Inorganic phosphate (Pi) is a central signaling molecule that modulates virulence in various pathogens. In Pseudomonas aeruginosa, low Pi concentrations induce transcriptional alterations that increase virulence. Also, under low Pi levels, P. aeruginosa exhibits Pi chemotaxis—a process mediated by t...

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Main Authors:	Rico-Jiménez, Miriam, Reyes-Darias, Jose Antonio, Ortega, Álvaro, Díez Peña, Ana Isabel, Morel, Bertrand, Krell, Tino
Format:	Online
Language:	English
Published:	Nature Publishing Group 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926252/

id	pubmed-4926252
recordtype	oai_dc
spelling	pubmed-49262522016-07-01 Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa Rico-Jiménez, Miriam Reyes-Darias, Jose Antonio Ortega, Álvaro Díez Peña, Ana Isabel Morel, Bertrand Krell, Tino Article Inorganic phosphate (Pi) is a central signaling molecule that modulates virulence in various pathogens. In Pseudomonas aeruginosa, low Pi concentrations induce transcriptional alterations that increase virulence. Also, under low Pi levels, P. aeruginosa exhibits Pi chemotaxis—a process mediated by the two non-paralogous receptors CtpH and CtpL. Here we show that the two receptors operate via different mechanisms. We demonstrate that the ligand binding domain (LBD) of CtpH but not CtpL binds Pi directly. We identify the periplasmic ligand binding protein PstS as the protein that binds in its Pi loaded state to CtpL, resulting in receptor stimulation. PstS forms part of the Pi transporter and has thus a double function in Pi transport and chemotaxis. The affinity of Pi for CtpH was modest whereas that for PstS very high, which may explain why CtpH and CtpL mediate chemotaxis to high and low Pi concentrations, respectively. The pstS/ctpH double mutant was almost devoid of Pi taxis, indicating that PstS is the only CtpL Pi-shuttle. Chemotaxis mechanisms based on indirect ligand recognition were unambiguously identified in enterobacteria. The discovery of a similar mechanism in a different bacterial order, involving a different chemoreceptor type and chemoeffector suggests that such systems are widespread. Nature Publishing Group 2016-06-29 /pmc/articles/PMC4926252/ /pubmed/27353565 http://dx.doi.org/10.1038/srep28967 Text en Copyright © 2016, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Rico-Jiménez, Miriam Reyes-Darias, Jose Antonio Ortega, Álvaro Díez Peña, Ana Isabel Morel, Bertrand Krell, Tino
spellingShingle	Rico-Jiménez, Miriam Reyes-Darias, Jose Antonio Ortega, Álvaro Díez Peña, Ana Isabel Morel, Bertrand Krell, Tino Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
author_facet	Rico-Jiménez, Miriam Reyes-Darias, Jose Antonio Ortega, Álvaro Díez Peña, Ana Isabel Morel, Bertrand Krell, Tino
author_sort	Rico-Jiménez, Miriam
title	Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
title_short	Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
title_full	Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
title_fullStr	Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
title_full_unstemmed	Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa
title_sort	two different mechanisms mediate chemotaxis to inorganic phosphate in pseudomonas aeruginosa
description	Inorganic phosphate (Pi) is a central signaling molecule that modulates virulence in various pathogens. In Pseudomonas aeruginosa, low Pi concentrations induce transcriptional alterations that increase virulence. Also, under low Pi levels, P. aeruginosa exhibits Pi chemotaxis—a process mediated by the two non-paralogous receptors CtpH and CtpL. Here we show that the two receptors operate via different mechanisms. We demonstrate that the ligand binding domain (LBD) of CtpH but not CtpL binds Pi directly. We identify the periplasmic ligand binding protein PstS as the protein that binds in its Pi loaded state to CtpL, resulting in receptor stimulation. PstS forms part of the Pi transporter and has thus a double function in Pi transport and chemotaxis. The affinity of Pi for CtpH was modest whereas that for PstS very high, which may explain why CtpH and CtpL mediate chemotaxis to high and low Pi concentrations, respectively. The pstS/ctpH double mutant was almost devoid of Pi taxis, indicating that PstS is the only CtpL Pi-shuttle. Chemotaxis mechanisms based on indirect ligand recognition were unambiguously identified in enterobacteria. The discovery of a similar mechanism in a different bacterial order, involving a different chemoreceptor type and chemoeffector suggests that such systems are widespread.
publisher	Nature Publishing Group
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926252/
_version_	1613601360989650944

Two different mechanisms mediate chemotaxis to inorganic phosphate in Pseudomonas aeruginosa

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