Z-ring Dynamics in E. coli

by Guy Allis

Dept of Physics, Ben Gurion University

at Biological and soft-matter physics

Tue, 20 Sep 2022, 15:00
Sacta-Rashi Building for Physics (54), room 207

Abstract

Bacterial cell division has been extensively studied for many years, especially for rod-shaped Escherichia coli. The FtsZ protein is a principal component of the cell division machinery, the divisome, as it coordinates the assembly of the proteins involved in septum wall synthesis necessary to ensure successful cell septation. During division, FtsZ polymerizes on the cytoplasmic face of the inner cell membrane to form a ring-like structure, the Z-ring, at the mid-cell region and recruits more than 30 different proteins to the division site. The current perception of the Z-ring is that of a rotating structure resulting from the treadmilling of its FtsZ filaments. Elements of this structure are highly dynamic and its motion correlates with the dynamics of the peptidoglycan synthesizing enzymes contained in the divisome. It remains an open question as to how this dynamic Z-ring is associated with septum formation and how it leads to the emergence of symmetric constriction. In our research, we address this question by tracking FtsZ clusters of live E. coli cells using customized image analysis algorithms. We find that the motion of the FtsZ clusters is significantly more complex than a simple rotation including tracks that are localized, others that display rapid changes in the direction of motion and also tracks that are apparently random in nature. Using Mean-Square Displacement (MSD) analysis we find that the motion of the FtsZ clusters is mainly diffusive rather than directed. We also present preliminary results using a superresolution approach to the imaging of the Z-ring, namely, Super–Resolution Radial Fluctuations (SRRF), an image processing approach that would allow resolving the finner structure of the Z-ring, which is typically below the optical resolution (~250 nm).

Created on 12-09-2022 by Feingold, Mario (mario)
Updaded on 12-09-2022 by Feingold, Mario (mario)