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Updated: Jul 10, 2026
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Biomimetic Materials to Characterize Bacteria-host Interactions
Published on: November 16, 2015
A photosensory two-component system regulates bacterial cell attachment.
Erin B Purcell1, Dan Siegal-Gaskins, David C Rawling
1Departments of Biochemistry and Molecular Biology and Physics, and The Committee on Microbiology, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA.
Summary
Blue light activates bacterial LOV-histidine kinase LovK, regulating cell attachment in Caulobacter crescentus. This photoreceptor
Area of Science:
- Microbiology
- Molecular Biology
- Photobiology
Background:
- Flavin-binding LOV domains are blue-light sensors in eukaryotes, regulating development and circadian rhythms.
- LOV domains are also found in bacterial sensor histidine kinases, but their prokaryotic function is poorly understood.
- Caulobacter crescentus possesses a two-component system, LovK (LOV-histidine kinase) and LovR (response regulator).
Purpose of the Study:
- To elucidate the function of the prokaryotic LOV-histidine kinase, LovK, and its regulator, LovR, in Caulobacter crescentus.
- To investigate the role of light in regulating bacterial cell-cell attachment via the LovK-LovR system.
Main Methods:
- Biochemical characterization of LovK's light-dependent activity (ATPase, autophosphorylation).
- Genetic analysis using gene deletion (lovR) and overexpression (lovK and lovR) strains.
- Microscopy and cell attachment assays under varying light conditions.
Main Results:
- LovK binds flavin, undergoes a photocycle, and shows light-enhanced enzymatic activity.
- Deletion of lovR impairs cell attachment; lovK-lovR overexpression increases cell-cell attachment, dependent on phosphorylation sites.
- Blue light significantly enhances cell-cell attachment in the lovK-lovR overexpression strain.
- A conserved cysteine in LovK's LOV domain is crucial for light-dependent regulation and enhanced attachment.
Conclusions:
- The LovK-LovR system in Caulobacter crescentus functions as a blue-light-regulated two-component system.
- Light modulates bacterial intercellular adhesion through the photoreceptor LovK and response regulator LovR.
- This study defines a novel light-sensing mechanism controlling bacterial behavior in prokaryotes.
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