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The essential Rhodobacter sphaeroides CenKR two-component system regulates cell division and envelope biosynthesis
Bryan D Lakey1,2, Kevin S Myers1, François Alberge1
1Wisconsin Energy Institute, Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
Plos Genetics
|June 29, 2022
Summary
Researchers identified an essential bacterial cell envelope kinase and regulator (CenKR) in Rhodobacter sphaeroides. This system directly controls cell envelope maintenance and outer membrane protein complex genes, impacting bacterial morphology.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Physiology
Background:
- Bacterial two-component systems (TCSs) regulate diverse cellular processes via signal transduction.
- Many TCSs are well-characterized in Gram-negative bacteria like E. coli, but less is known about their function in α-proteobacteria.
- Understanding extracytoplasmic regulation in α-proteobacteria is crucial due to the lack of known homologs to common TCSs.
Purpose of the Study:
- To identify and characterize a novel essential TCS in the α-proteobacterium Rhodobacter sphaeroides.
- To elucidate the role of this TCS in cell envelope maintenance and morphology.
- To identify direct and indirect targets of this TCS.
Main Methods:
- Genetic manipulation and biochemical assays to study phosphotransfer between TCS components.
- In vivo activity modulation of the TCS.
- Chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) to identify target genes.
- Analysis of morphological changes upon TCS modulation.
Main Results:
- Identification of an essential TCS, CenKR (Cell envelope Kinase and Regulator), in R. sphaeroides.
- Demonstration that modulation of CenKR activity leads to significant morphological changes.
- ChIP-seq and RNA-seq revealed that CenKR directly regulates genes involved in cell envelope maintenance, including subunits of the Tol-Pal complex.
- Indirect regulation of peptidoglycan biosynthetic genes was also observed.
Conclusions:
- CenKR is essential for cell envelope maintenance in R. sphaeroides.
- This study reports the first TCS shown to directly control Tol-Pal machinery gene expression in Gram-negative bacteria.
- Homologs of CenKR likely play similar roles in other α-proteobacteria, potentially regulating unknown cell envelope processes.
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