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Proc Natl Acad Sci U S A. 2016 Feb 23;113(8):E1044-53. doi: 10.1073/pnas.1514296113. Epub 2016 Feb 1.

Defining the rate-limiting processes of bacterial cytokinesis.

Author information

1
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
2
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205 xiao@jhmi.edu.

Abstract

Bacterial cytokinesis is accomplished by the essential 'divisome' machinery. The most widely conserved divisome component, FtsZ, is a tubulin homolog that polymerizes into the 'FtsZ-ring' ('Z-ring'). Previous in vitro studies suggest that Z-ring contraction serves as a major constrictive force generator to limit the progression of cytokinesis. Here, we applied quantitative superresolution imaging to examine whether and how Z-ring contraction limits the rate of septum closure during cytokinesis in Escherichia coli cells. Surprisingly, septum closure rate was robust to substantial changes in all Z-ring properties proposed to be coupled to force generation: FtsZ's GTPase activity, Z-ring density, and the timing of Z-ring assembly and disassembly. Instead, the rate was limited by the activity of an essential cell wall synthesis enzyme and further modulated by a physical divisome-chromosome coupling. These results challenge a Z-ring-centric view of bacterial cytokinesis and identify cell wall synthesis and chromosome segregation as limiting processes of cytokinesis.

KEYWORDS:

FtsZ; cell wall synthesis; cytokinesis; force generation; superresolution

PMID:
26831086
PMCID:
PMC4776500
DOI:
10.1073/pnas.1514296113
[Indexed for MEDLINE]
Free PMC Article

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