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PMID:23357388
| Citation |
Houppert, AS, Bohman, L, Merritt, PM, Cole, CB, Caulfield, AJ, Lathem, WW and Marketon, MM (2013) RfaL is required for Yersinia pestis type III secretion and virulence. Infect. Immun. 81:1186-97 |
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| Abstract |
Yersinia pestis, the causative agent of plague, uses a type III secretion system (T3SS) to inject cytotoxic Yop proteins directly into the cytosol of mammalian host cells. The T3SS can also be activated in vitro at 37°C in the absence of calcium. The chromosomal gene rfaL (waaL) was recently identified as a virulence factor required for proper function of the T3SS. RfaL functions as a ligase that adds the terminal N-acetylglucosamine to the lipooligosaccharide core of Y. pestis. We previously showed that deletion of rfaL prevents secretion of Yops in vitro. Here we show that the divalent cations calcium, strontium, and magnesium can partially or fully rescue Yop secretion in vitro, indicating that the secretion phenotype of the rfaL mutant may be due to structural changes in the outer membrane and the corresponding feedback inhibition on the T3SS. In support of this, we found that the defect can be overcome by deleting the regulatory gene lcrQ. Consistent with a defective T3SS, the rfaL mutant is less virulent than the wild type. We show here that the virulence defect of the mutant correlates with a decrease in both T3SS gene expression and ability to inject innate immune cells, combined with an increased sensitivity to cationic antimicrobial peptides. |
| Links |
PubMed PMC3639585 Online version:10.1128/IAI.01417-12 |
| Keywords |
Animals; Bacterial Load; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Bacterial Secretion Systems; Cations, Divalent/metabolism; Disease Models, Animal; Female; Gene Deletion; Ligases/genetics; Ligases/metabolism; Membrane Transport Proteins/genetics; Membrane Transport Proteins/metabolism; Metals/metabolism; Mice; Mice, Inbred C57BL; Plague/microbiology; Plague/pathology; Spleen/microbiology; Virulence; Virulence Factors/genetics; Virulence Factors/metabolism; Yersinia pestis/genetics; Yersinia pestis/pathogenicity |
Significance
Annotations
| Gene product | Qualifier | GO Term | Evidence Code | with/from | Aspect | Extension | Notes | Status |
|---|---|---|---|---|---|---|---|---|
| GO:0030254: protein secretion by the type III secretion system |
ECO:0007122: |
P |
Figure S1A shows the dependence on RfaL in the presence of calcium for secretion of late-phase type III secretion system proteins in Yersinia pestis through secretion assays followed by western blotting using anti YopD (early T3SS protein) and YopE (late T3SS protein) in WT, RfaL mutant, and RfaL complemented strains. YopD is still secreted in RfaL mutant in the absence of calcium, but to a lesser extent. submitted a new term request for an evidence code describing secretion assays - waiting on term. |
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Notes
See also
References
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