Stuttering Min oscillations within E. coli bacteria: A stochastic polymerization model

TL;DR

This study presents a stochastic 3D polymerization model to analyze Min protein oscillations in E. coli, revealing how filament dynamics influence oscillation speed and stuttering frequency.

Contribution

The paper introduces a novel 3D off-lattice stochastic model to explain Min oscillation stuttering and its dependence on filament processes, advancing understanding of bacterial cell division regulation.

Findings

Processivity, tip-protection, and fragmentation influence stuttering and oscillation speed.

Short MinD filaments correlate with infrequent stuttering in standard oscillations.

Higher stuttering rates suggest longer MinD filaments, useful for experimental diagnostics.

Abstract

We have developed a 3D off-lattice stochastic polymerization model to study subcellular oscillation of Min proteins in the bacteria Escherichia coli, and used it to investigate the experimental phenomenon of Min oscillation stuttering. Stuttering was affected by the rate of immediate rebinding of MinE released from depolymerizing filament tips (processivity), protection of depolymerizing filament tips from MinD binding, and fragmentation of MinD filaments due to MinE. Each of processivity, protection, and fragmentation reduces stuttering, speeds oscillations, and reduces MinD filament lengths. Neither processivity or tip-protection were, on their own, sufficient to produce fast stutter-free oscillations. While filament fragmentation could, on its own, lead to fast oscillations with infrequent stuttering; high levels of fragmentation degraded oscillations. The infrequent stuttering observed in standard Min oscillations are consistent with short filaments of MinD, while we expect that mutants that exhibit higher stuttering frequencies will exhibit longer MinD filaments. Increased stuttering rate may be a useful diagnostic to find observable MinD polymerization in experimental conditions.