The phosphatase activity is the target for Mg2+ regulation of the sensor protein PhoQ in Salmonella

CASTELLI, M. E.; GARCÍA VÉSCOVI, E.; SONCINI, F. C.

JOURNAL OF BIOLOGICAL CHEMISTRY

American Society for Biochemistry and Molecular Biology

Año: 2000 vol. 275 p. 22948 - 22954

0021-9258

The PhoP/PhoQ two-component system controls the expression of essential virulence traits in the pathogenic bacterium Salmonella enterica serovar Typhimurium. Environmental deprivation of Mg21 activates the PhoP/PhoQ signal transduction cascade, which results in an increased expression of genes necessary for survival inside the host. It was previously demonstrated that the interaction of Mg21 with the periplasmic domain of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 2 the PhoP/PhoQ signal transduction cascade, which results in an increased expression of genes necessary for survival inside the host. It was previously demonstrated that the interaction of Mg21 with the periplasmic domain of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 2 21 activates the PhoP/PhoQ signal transduction cascade, which results in an increased expression of genes necessary for survival inside the host. It was previously demonstrated that the interaction of Mg21 with the periplasmic domain of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 2 21 with the periplasmic domain of PhoQ promotes a conformational change in the sensor protein that leads to the down-regulation of PhoP-activated genes. We have now examined the regulatory effect of Mg21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg212 membrane-bound PhoQ. We demonstrated that Mg212 21 on the putative activities of the membrane-bound PhoQ. We demonstrated that Mg2121 promotes a phospho-PhoP phosphatase activity in the sensor protein. This activity depends on the intactness of the conserved His-277, suggesting that the phosphatase active site overlaps the H box. The integrity of the N-terminal domain of PhoQ was essential for the induction of the phosphatase activity, because Mg21 did not stimulate the release of inorganic phosphate from phospho- PhoP in a fusion protein that lacks this sensing domain. These findings reveal that the sensor PhoQ harbors a phospho-PhoP phosphatase activity, and that this phosphatase activity is the target of the extracellular Mg21-triggered regulation of the PhoP/PhoQ system.2 stimulate the release of inorganic phosphate from phospho- PhoP in a fusion protein that lacks this sensing domain. These findings reveal that the sensor PhoQ harbors a phospho-PhoP phosphatase activity, and that this phosphatase activity is the target of the extracellular Mg21-triggered regulation of the PhoP/PhoQ system.2 21 did not stimulate the release of inorganic phosphate from phospho- PhoP in a fusion protein that lacks this sensing domain. These findings reveal that the sensor PhoQ harbors a phospho-PhoP phosphatase activity, and that this phosphatase activity is the target of the extracellular Mg21-triggered regulation of the PhoP/PhoQ system.21-triggered regulation of the PhoP/PhoQ system.