The PomXYZ Proteins Self-Organize on the Bacterial Nucleoid to Stimulate Cell Division

Publication date: 8 May 2017
Source:Developmental Cell, Volume 41, Issue 3
Author(s): Dominik Schumacher, Silke Bergeler, Andrea Harms, Janet Vonck, Sabrina Huneke-Vogt, Erwin Frey, Lotte Søgaard-Andersen
Cell division site positioning is precisely regulated to generate correctly sized and shaped daughters. We uncover the strategy used by the social bacterium Myxococcus xanthus to position the FtsZ cytokinetic ring at midcell. PomX, PomY, and the nucleoid-binding ParA/MinD ATPase PomZ self-assemble forming a large nucleoid-associated complex that localizes at the division site before FtsZ to directly guide and stimulate division. PomXYZ localization is generated through self-organized biased random motion on the nucleoid toward midcell and constrained motion at midcell. Experiments and theory show that PomXYZ motion is produced by diffusive PomZ fluxes on the nucleoid into the complex. Flux differences scale with the intracellular asymmetry of the complex and are converted into a local PomZ concentration gradient across the complex with translocation toward the higher PomZ concentration. At midcell, fluxes equalize resulting in constrained motion. Flux-based mechanisms may represent a general paradigm for positioning of macromolecular structures in bacteria.

Teaser

Schumacher et al. find that the PomXYZ complex self-organizes on the bacterial nucleoid and promotes positioning of the cytokinetic ring. Diffusive fluxes of PomZ into the complex scale with intracellular asymmetry and are converted into a local PomZ concentration gradient that promotes biased motion toward and constrained motion at midcell.


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