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Updated: Nov 23, 2025
Fluorescence Live-cell Imaging of the Complete Vegetative Cell Cycle of the Slow-growing Social Bacterium Myxococcus xanthus
Published on: June 20, 2018
PlpA, a PilZ-like protein, regulates directed motility of the bacterium Myxococcus xanthus
Connor B Pogue1, Tianyi Zhou1, Beiyan Nan1
1Department of Biology, Texas A&M University, College Station, TX 77843, USA.
Abstract:
The rod-shaped bacterium Myxococcus xanthus moves on surfaces along its long cell axis and reverses its moving direction regularly. Current models propose that the asymmetric localization of a Ras-like GTPase, MglA, to leading cell poles determines the moving direction of cells. However, cells are still motile in the mutants where MglA localizes symmetrically, suggesting the existence of additional regulators that control moving direction. In this study, we identified PlpA, a PilZ-like protein that regulates the direction of motility. PlpA and MglA localize into opposite asymmetric patterns. Deletion of the plpA gene abolishes the asymmetry of MglA localization, increases the frequency of cellular reversals and leads to severe defects in cell motility. By tracking the movements of single motor particles, we demonstrated that PlpA and MglA co-regulated the direction of gliding motility through direct interactions with the gliding motor. PlpA inhibits the reversal of individual gliding motors while MglA promotes motor reversal. By counteracting MglA near lagging cell poles, PlpA reinforces the polarity axis of MglA and thus stabilizes the direction of motility.
Insights
Researchers discovered PlpA, a protein regulating bacterial movement direction in Myxococcus xanthus. PlpA and MglA proteins interact to control cell motility and direction, preventing frequent reversals.
Area of Science:
- Microbiology
- Cell Biology
- Bacterial Motility
Background:
- Myxococcus xanthus exhibits directional movement and regular reversals.
- Asymmetric localization of Ras-like GTPase MglA is thought to determine cell direction.
- MglA's symmetric localization in mutants still allows motility, indicating other regulators exist.
Purpose of the Study:
- Identify novel regulators of Myxococcus xanthus motility direction.
- Investigate the role of PlpA in controlling cell movement and reversals.
- Elucidate the interaction between PlpA and MglA in regulating motility.
Main Methods:
- Genetic analysis of Myxococcus xanthus mutants.
- Protein localization studies using microscopy.
- Single motor particle tracking to analyze motility dynamics.
Main Results:
- PlpA, a PilZ-like protein, was identified as a motility regulator.
- PlpA and MglA exhibit opposing asymmetric localization patterns.
- PlpA deletion disrupts MglA asymmetry, increases reversals, and impairs motility.
- PlpA and MglA directly interact with the gliding motor, with PlpA inhibiting and MglA promoting motor reversal.
Conclusions:
- PlpA is a key regulator of Myxococcus xanthus motility direction.
- PlpA and MglA form a regulatory system controlling gliding motor reversal.
- PlpA stabilizes motility direction by counteracting MglA at lagging cell poles.
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