Limits...
Calprotectin Increases the Activity of the SaeRS Two Component System and Murine Mortality during Staphylococcus aureus Infections.

Cho H, Jeong DW, Liu Q, Yeo WS, Vogl T, Skaar EP, Chazin WJ, Bae T - PLoS Pathog. (2015)

Bottom Line: The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression.During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality.These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

View Article: PubMed Central - PubMed

Affiliation: Indiana University School of Medicine-Northwest, Gary, Indiana, United States of America.

ABSTRACT
Calprotectin, the most abundant cytoplasmic protein in neutrophils, suppresses the growth of Staphylococcus aureus by sequestering the nutrient metal ions Zn and Mn. Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus. The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression. During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality. These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

No MeSH data available.


Related in: MedlinePlus

Cu and Zn inhibit the autokinase activity of SaeS.(A) The effect of Fe, Zn and Cu on the autokinase activity of SaeS. MBP-SaeS (3 μM) was autophosphorylated with [γ-32P]-ATP for 15 min in the presence of various concentrations of FeSO4, ZnSO4, and CuSO4. Then the phosphorylation of SaeS was measured by SDS-PAGE and autoradiograph (top) and quantified (bottom). (B) The effect of Zn on the autokinase activity of SaeS in purified cell membranes. Cell membranes (25 μg) containing overexpressed SaeS were used as a source of SaeS. The experiment was carried out as described above. The autoradiograph (top) and quantification of the results (bottom) are shown.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4492782&req=5

ppat.1005026.g002: Cu and Zn inhibit the autokinase activity of SaeS.(A) The effect of Fe, Zn and Cu on the autokinase activity of SaeS. MBP-SaeS (3 μM) was autophosphorylated with [γ-32P]-ATP for 15 min in the presence of various concentrations of FeSO4, ZnSO4, and CuSO4. Then the phosphorylation of SaeS was measured by SDS-PAGE and autoradiograph (top) and quantified (bottom). (B) The effect of Zn on the autokinase activity of SaeS in purified cell membranes. Cell membranes (25 μg) containing overexpressed SaeS were used as a source of SaeS. The experiment was carried out as described above. The autoradiograph (top) and quantification of the results (bottom) are shown.

Mentions: As a sensor kinase, SaeS possesses autokinase, phosphotransferase, and phosphatase activities. To further understand the metal-mediated repression of the SaeRS TCS, we purified MBP (maltose-binding protein)-SaeS and examined the response of the enzymatic activities of SaeS to the metal ions. The autophosphorylation of SaeS was significantly inhibited by 10 μM Zn or 50 μM Cu (Fig 2A), suggesting that the divalent Zn and Cu ions represses the autokinase activity of SaeS. Fe did not inhibit the SaeS autokinase activity until the concentration reaches 500 μM, indicating that, at its physiological concentration, Fe does not inhibit SaeS autokinase activity. Neither the transfer of phosphoryl group from SaeS to SaeR (i.e., phosphotransferase activity) nor the level of phosphorylated SaeR (i.e., phosphatase activity) was affected by the metal ions (S1 Fig), suggesting that Cu and Zn specifically inhibit the autokinase activity of SaeS. Since SaeS is embedded in the cell membrane, we overexpressed SaeS in the strain USA300, purified the cell membranes and repeated the autokinase assay for Zn with the purified cell membranes. As shown in Fig 2B, Zn inhibited the phosphorylation of SaeS in the cell membrane in a concentration-dependent manner.


Calprotectin Increases the Activity of the SaeRS Two Component System and Murine Mortality during Staphylococcus aureus Infections.

Cho H, Jeong DW, Liu Q, Yeo WS, Vogl T, Skaar EP, Chazin WJ, Bae T - PLoS Pathog. (2015)

Cu and Zn inhibit the autokinase activity of SaeS.(A) The effect of Fe, Zn and Cu on the autokinase activity of SaeS. MBP-SaeS (3 μM) was autophosphorylated with [γ-32P]-ATP for 15 min in the presence of various concentrations of FeSO4, ZnSO4, and CuSO4. Then the phosphorylation of SaeS was measured by SDS-PAGE and autoradiograph (top) and quantified (bottom). (B) The effect of Zn on the autokinase activity of SaeS in purified cell membranes. Cell membranes (25 μg) containing overexpressed SaeS were used as a source of SaeS. The experiment was carried out as described above. The autoradiograph (top) and quantification of the results (bottom) are shown.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492782&req=5

ppat.1005026.g002: Cu and Zn inhibit the autokinase activity of SaeS.(A) The effect of Fe, Zn and Cu on the autokinase activity of SaeS. MBP-SaeS (3 μM) was autophosphorylated with [γ-32P]-ATP for 15 min in the presence of various concentrations of FeSO4, ZnSO4, and CuSO4. Then the phosphorylation of SaeS was measured by SDS-PAGE and autoradiograph (top) and quantified (bottom). (B) The effect of Zn on the autokinase activity of SaeS in purified cell membranes. Cell membranes (25 μg) containing overexpressed SaeS were used as a source of SaeS. The experiment was carried out as described above. The autoradiograph (top) and quantification of the results (bottom) are shown.
Mentions: As a sensor kinase, SaeS possesses autokinase, phosphotransferase, and phosphatase activities. To further understand the metal-mediated repression of the SaeRS TCS, we purified MBP (maltose-binding protein)-SaeS and examined the response of the enzymatic activities of SaeS to the metal ions. The autophosphorylation of SaeS was significantly inhibited by 10 μM Zn or 50 μM Cu (Fig 2A), suggesting that the divalent Zn and Cu ions represses the autokinase activity of SaeS. Fe did not inhibit the SaeS autokinase activity until the concentration reaches 500 μM, indicating that, at its physiological concentration, Fe does not inhibit SaeS autokinase activity. Neither the transfer of phosphoryl group from SaeS to SaeR (i.e., phosphotransferase activity) nor the level of phosphorylated SaeR (i.e., phosphatase activity) was affected by the metal ions (S1 Fig), suggesting that Cu and Zn specifically inhibit the autokinase activity of SaeS. Since SaeS is embedded in the cell membrane, we overexpressed SaeS in the strain USA300, purified the cell membranes and repeated the autokinase assay for Zn with the purified cell membranes. As shown in Fig 2B, Zn inhibited the phosphorylation of SaeS in the cell membrane in a concentration-dependent manner.

Bottom Line: The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression.During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality.These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

View Article: PubMed Central - PubMed

Affiliation: Indiana University School of Medicine-Northwest, Gary, Indiana, United States of America.

ABSTRACT
Calprotectin, the most abundant cytoplasmic protein in neutrophils, suppresses the growth of Staphylococcus aureus by sequestering the nutrient metal ions Zn and Mn. Here we show that calprotectin can also enhance the activity of the SaeRS two component system (TCS), a signaling system essential for production of over 20 virulence factors in S. aureus. The activity of the SaeRS TCS is repressed by certain divalent ions found in blood or neutrophil granules; however, the Zn bound-form of calprotectin relieves this repression. During staphylococcal encounter with murine neutrophils or staphylococcal infection of the murine peritoneal cavity, calprotectin increases the activity of the SaeRS TCS as well as the production of proinflammatory cytokines such as IL-1β and TNF-α, resulting in higher murine mortality. These results suggest that, under certain conditions, calprotectin can be exploited by S. aureus to increase bacterial virulence and host mortality.

No MeSH data available.


Related in: MedlinePlus