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Parallel quorum-sensing system in Vibrio cholerae prevents signal interference inside the host
Samit Watve1, Kelsey Barrasso1,2, Sarah A Jung1,2
1Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America.
Plos Pathogens
|February 15, 2020
Summary
Ethanolamine, an intestinal metabolite, interferes with Vibrio cholerae quorum sensing (QS) by interacting with the CqsR receptor. This interference is masked by redundant QS pathways, ensuring robust host colonization.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Bacteria utilize quorum sensing (QS) for population density-dependent regulation of virulence.
- Vibrio cholerae employs four histidine kinases (LuxPQ, CqsS, CqsR, VpsS) as QS receptors.
- Redundancy in QS receptors suggests a mechanism to prevent interference, but environmental triggers remain unclear.
Purpose of the Study:
- To identify natural molecules that interfere with Vibrio cholerae QS.
- To investigate the role of CqsR in host colonization and QS interference.
- To elucidate the mechanism by which ethanolamine affects QS.
Main Methods:
- Generation and analysis of V. cholerae mutants lacking specific QS receptors.
- Identification of ethanolamine as a QS interfering molecule.
- Biochemical assays to determine ethanolamine's interaction with the CqsR receptor's CACHE domain.
- Assessment of QS gene expression and host colonization in response to ethanolamine.
Main Results:
- Mutants expressing only CqsR showed defects in large intestine colonization.
- Ethanolamine was identified as an intestinal metabolite that interferes with CqsR-mediated QS.
- Ethanolamine specifically binds to the CqsR CACHE domain, inducing premature QS response.
- Mutations disrupting CqsR signal sensing abolished ethanolamine's effect.
- V. cholerae lacking ethanolamine production remained proficient in QS.
Conclusions:
- Ethanolamine acts as an external cue interfering with CqsR signaling.
- The presence of parallel QS pathways masks ethanolamine's inhibitory effect, ensuring robust V. cholerae colonization.
- Understanding QS interference mechanisms is crucial for controlling bacterial virulence.
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