INVESTIGADORES
GARCIA VESCOVI Eleonora
artículos
Título:
The phosphatase activity is the target for Mg2+ regulation of the sensor protein PhoQ in Salmonella
Autor/es:
CASTELLI, M. E.; GARCÍA VÉSCOVI, E.; SONCINI, F. C.
Revista:
JOURNAL OF BIOLOGICAL CHEMISTRY
Editorial:
American Society for Biochemistry and Molecular Biology
Referencias:
Año: 2000 vol. 275 p. 22948 - 22954
ISSN:
0021-9258
Resumen:
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.