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Updated: Jun 15, 2025
Fluorescence Live-cell Imaging of the Complete Vegetative Cell Cycle of the Slow-growing Social Bacterium Myxococcus xanthus
Published on: June 20, 2018
Functional investigation of the two ClpPs and three ClpXs in Myxococcus xanthus DK1622
Tianyu Wan1, Ying Cao1, Ya-Jun Lai1
1State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China.
Abstract:
ClpXP is a protease complex that plays important roles in protein quality control and cell cycle regulation, but the functions of multiple ClpXs and multiple ClpPs in M. xanthus remain unknown. The genome of Myxococcus xanthus DK1622 contains two clpPs and three clpXs. The clpP1 and clpX1 genes are cotranscribed and are both essential, while the other copies are isolated in the genome and are deletable. The deletion of clpX2 caused the mutant to be deficient in fruiting body development, while the clpX3 gene is involved in resistance to thermal stress. Both ClpPs possess catalytic active sites, but only ClpP1 shows in vitro peptidase activity on the typical substrate Suc-LY-AMC. All of these clpP and clpX genes exhibit strong transcriptional upregulation in the stationary phase, and the transcription of the three clpX genes appears to be coordinated. Our results demonstrated that multiple ClpPs and multiple ClpXs are functionally divergent and may assist in the environmental adaptation and functional diversification of M. xanthus.IMPORTANCEClpXP is an important protease complex of bacteria and is involved in various physiological processes. Myxococcus xanthus DK1622 possesses two ClpPs and three ClpXs with unclear functions. We investigated the functions of these genes and demonstrated the essential roles of clpP1 and clpX1. Only ClpP1 has in vitro peptidase activity on Suc-LY-AMC, and the isolated clpX copies participate in distinct cellular processes. All of these genes exhibited significant transcriptional upregulation in the stationary phase. Divergent functions appear in multiple ClpPs and multiple ClpXs in M. xanthus DK1622.
Insights
Multiple ClpP and ClpX protease components in Myxococcus xanthus exhibit distinct functions. Essential ClpP1 and ClpX1 are vital, while other copies aid adaptation and stress resistance.
Area of Science:
- Bacterial protein homeostasis
- Molecular microbiology
- Enzyme function
Background:
- The ClpXP protease complex is crucial for bacterial protein quality control and cell cycle regulation.
- Myxococcus xanthus DK1622 possesses two ClpP and three ClpX genes with largely unknown functions.
Purpose of the Study:
- To elucidate the distinct roles of multiple ClpP and ClpX components in Myxococcus xanthus.
- To investigate the functional divergence and regulation of these protease genes.
Main Methods:
- Gene deletion and mutational analysis to assess phenotypic consequences.
- In vitro peptidase activity assays using Suc-LY-AMC substrate.
- Transcriptional analysis to study gene expression patterns.
Main Results:
- ClpP1 and ClpX1 are essential genes, with ClpP1 exhibiting in vitro peptidase activity.
- ClpX2 deletion impairs fruiting body development, while ClpX3 confers thermal stress resistance.
- All ClpP and ClpX genes are upregulated in the stationary phase, with coordinated transcription of ClpX genes.
Conclusions:
- Multiple ClpPs and ClpXs in M. xanthus are functionally divergent.
- These divergent proteases contribute to environmental adaptation and functional diversification.
- The coordinated regulation suggests complex roles in stationary phase physiology.
