SciLifeLab The Svedberg seminar series 2014-06-02
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, School of Medicine, Baltimore, MD, US
Bacterial cell division in superresolution
Cell division is essential for the survival and development of all organisms. In prokaryotes, the FtsZ protein, a tubulin-like GTPase, plays a central role. FtsZ is highly conserved across bacterial species and has been identified as a novel drug target for antimicrobial therapy. In vivo FtsZ assembles into a supramolecular ring-like structure (hence named the Z-ring) at the leading edge of the invaginating membrane. The Z-ring serves as an essential scaffold to recruit all other division proteins and generates contractile force for cytokinesis. Despite the essential role of the Z-ring in bacterial cell division, it is not known what the structure of the Z-ring is or how the contractile force is generated.
We employ the newly developed single-molecule-based superresolution imaging technique to characterize the three-dimensional structure of the Z-ring in E. coli. We found that the Z-ring is likely composed of a loose bundle of FtsZ protofilaments that randomly overlap with each other in three dimensions. During constriction, the Z-ring condenses and finally collapses toward the end of septum closure . Furthermore, we found that the Z-ring is secured in a multi-layered protein network extending from membrane to chromosome. This extended protein network may play important roles in placing the Z-ring at the midcell, maintaining its structural integrity, and coordinate cell wall constriction with chromosome segregation.
Host: Johan Elf