Abstract
The histidine sensor kinase (HK) QseC senses autoinducer 3 (AI-3) and the adrenergic hormones epinephrine and norepinephrine. Upon sensing these signals, QseC acts through three response regulators (RRs) to regulate the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). The QseB, QseF, and KdpE RRs that are phosphorylated by QseC constitute a tripartite signaling cascade having different and overlapping targets, including flagella and motility, the type three secretion system encoded by the locus of enterocyte effacement (LEE), and Shiga toxin. We modeled the tertiary structure of QseC's periplasmic sensing domain and aligned the sequences from 12 different species to identify the most conserved amino acids. We selected eight amino acids conserved in all of these QseC homologues. The corresponding QseC site-directed mutants were expressed and still able to autophosphorylate; however, four mutants demonstrated an increased basal level of phosphorylation. These mutants have differential flagellar, motility, LEE, and Shiga toxin expression phenotypes. We selected four mutants for more in-depth analyses and found that they differed in their ability to phosphorylate QseB, KdpE, and QseF. This suggests that these mutations in the periplasmic sensing domain affected the region downstream of the QseC signaling cascade and therefore can influence which pathway QseC regulates.
| Original language | English (US) |
|---|---|
| Article number | e00861-16 |
| Journal | Journal of Bacteriology |
| Volume | 199 |
| Issue number | 8 |
| DOIs | |
| State | Published - Apr 1 2017 |
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Keywords
- EHEC
- Enterohemorrhagic E. coli
- LEE
- QseC
- Two-component system
ASJC Scopus subject areas
- Microbiology
- Molecular Biology
Cite this
Genetic and mechanistic analyses of the periplasmic domain of the enterohemorrhagic Escherichia coli QseC histidine sensor kinase. / Parker, Christopher T.; Russell, Regan; Njoroge, Jacqueline W.; Jimenez, Angel G.; Taussig, Ron; Sperandio, Vanessa.
In: Journal of Bacteriology, Vol. 199, No. 8, e00861-16, 01.04.2017.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Genetic and mechanistic analyses of the periplasmic domain of the enterohemorrhagic Escherichia coli QseC histidine sensor kinase
AU - Parker, Christopher T.
AU - Russell, Regan
AU - Njoroge, Jacqueline W.
AU - Jimenez, Angel G.
AU - Taussig, Ron
AU - Sperandio, Vanessa
PY - 2017/4/1
Y1 - 2017/4/1
N2 - The histidine sensor kinase (HK) QseC senses autoinducer 3 (AI-3) and the adrenergic hormones epinephrine and norepinephrine. Upon sensing these signals, QseC acts through three response regulators (RRs) to regulate the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). The QseB, QseF, and KdpE RRs that are phosphorylated by QseC constitute a tripartite signaling cascade having different and overlapping targets, including flagella and motility, the type three secretion system encoded by the locus of enterocyte effacement (LEE), and Shiga toxin. We modeled the tertiary structure of QseC's periplasmic sensing domain and aligned the sequences from 12 different species to identify the most conserved amino acids. We selected eight amino acids conserved in all of these QseC homologues. The corresponding QseC site-directed mutants were expressed and still able to autophosphorylate; however, four mutants demonstrated an increased basal level of phosphorylation. These mutants have differential flagellar, motility, LEE, and Shiga toxin expression phenotypes. We selected four mutants for more in-depth analyses and found that they differed in their ability to phosphorylate QseB, KdpE, and QseF. This suggests that these mutations in the periplasmic sensing domain affected the region downstream of the QseC signaling cascade and therefore can influence which pathway QseC regulates.
AB - The histidine sensor kinase (HK) QseC senses autoinducer 3 (AI-3) and the adrenergic hormones epinephrine and norepinephrine. Upon sensing these signals, QseC acts through three response regulators (RRs) to regulate the expression of virulence genes in enterohemorrhagic Escherichia coli (EHEC). The QseB, QseF, and KdpE RRs that are phosphorylated by QseC constitute a tripartite signaling cascade having different and overlapping targets, including flagella and motility, the type three secretion system encoded by the locus of enterocyte effacement (LEE), and Shiga toxin. We modeled the tertiary structure of QseC's periplasmic sensing domain and aligned the sequences from 12 different species to identify the most conserved amino acids. We selected eight amino acids conserved in all of these QseC homologues. The corresponding QseC site-directed mutants were expressed and still able to autophosphorylate; however, four mutants demonstrated an increased basal level of phosphorylation. These mutants have differential flagellar, motility, LEE, and Shiga toxin expression phenotypes. We selected four mutants for more in-depth analyses and found that they differed in their ability to phosphorylate QseB, KdpE, and QseF. This suggests that these mutations in the periplasmic sensing domain affected the region downstream of the QseC signaling cascade and therefore can influence which pathway QseC regulates.
KW - EHEC
KW - Enterohemorrhagic E. coli
KW - LEE
KW - QseC
KW - Two-component system
UR - http://www.scopus.com/inward/record.url?scp=85017110802&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85017110802&partnerID=8YFLogxK
U2 - 10.1128/JB.00861-16
DO - 10.1128/JB.00861-16
M3 - Article
C2 - 28138098
AN - SCOPUS:85017110802
VL - 199
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 8
M1 - e00861-16
ER -