Cross-linking FtsZ polymers into coherent Z rings

Alex Dajkovic, Sebastien Pichoff, Joe Lutkenhaus, Denis Wirtz

Research output: Contribution to journalArticlepeer-review

Abstract

A key event in bacterial cytokinesis is the formation of the Z ring, which serves as a mechanical scaffold that recruits other cytokinetic proteins to establish functional divisomes. This scaffolding function of Z rings is essential throughout cytokinesis, but the underlying molecular interactions are poorly understood. Here we report that a widely conserved FtsZ binding protein, ZapA, has cytological, biochemical and biophysical properties that argue for the importance of cross-linking interactions between FtsZ polymers in the coherence of Z rings. Escherichia coli zapA null mutant cells have Z rings that are structurally looser and many helical precursors of Z rings fail to coalesce into coherent rings. Biophysical behaviour of FtsZ in the presence of ZapA reveals that ZapA not only bundles, but also cross-links FtsZ polymers, which makes it the first cross-linking protein of the bacterial cytoskeleton. Cross-linking in vitro occurs at the stoichiometry of FtsZ-ZapA interaction at the Z rings in vivo, where nearly all intracellular ZapA is dynamically associated. ZapA also stabilizes longitudinal bonds between FtsZ monomers since it promotes the polymerization of FtsZ mutants with lesions at the polymerization interface and since it reverses the inhibitory effects of SulA, a known antagonist of FtsZ longitudinal interactions.

Original languageEnglish (US)
Pages (from-to)651-668
Number of pages18
JournalMolecular Microbiology
Volume78
Issue number3
DOIs
StatePublished - Nov 2010

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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