Dynamics of the Bacillus subtilis Min System.

Area of Science:

• Microbiology
• Cell Biology
• Biophysics

Background:

• The Min system regulates bacterial cell division site selection in rod-shaped bacteria.
• In Escherichia coli, the Min system oscillates pole-to-pole, creating a midcell minimum.
• In Bacillus subtilis, the Min system was thought to form a stationary bipolar gradient.

Purpose of the Study:

• To investigate the dynamic localization of the Min system in Bacillus subtilis.
• To determine if the Min system in B. subtilis exhibits dynamic behavior similar to E. coli.
• To understand the role of active septation in Min protein dynamics.

Main Methods:

• Construction of functional Min protein fusions via allelic exchange in B. subtilis.
• State-of-the-art imaging techniques to observe Min protein dynamics.
• Physical and mathematical modeling using measured diffusion constants.

Main Results:

• The Min system in B. subtilis localizes dynamically to active division sites, often in clusters.
• Observed Min protein enrichment at the septum is explained by physical modeling.
• Mathematical modeling indicates a dynamic equilibrium state for Min protein localization.

Conclusions:

• The Min system in B. subtilis exhibits dynamic behavior, localizing to active division sites.
• The molecular mechanisms of Min protein dynamics are conserved between E. coli and B. subtilis.
• The Min system plays a major role in controlling active division sites, not cell pole areas.