A new assembly pathway for the cytokinetic Z ring from a dynamic helical structure in vegetatively growing cells of Bacillus subtilis

Mol Microbiol. 2007 Apr;64(2):487-99. doi: 10.1111/j.1365-2958.2007.05673.x.


The earliest event in bacterial cell division is the formation of a Z ring, composed of the tubulin-like FtsZ protein, at the division site at midcell. This ring then recruits several other division proteins and together they drive the formation of a division septum between two replicated chromosomes. Here we show that, in addition to forming a cytokinetic ring, FtsZ localizes in a helical-like pattern in vegetatively growing cells of Bacillus subtilis. FtsZ moves rapidly within this helix-like structure. Examination of FtsZ localization in individual live cells undergoing a single cell cycle suggests a new assembly mechanism for Z ring formation that involves a cell cycle-mediated multistep remodelling of FtsZ polymers. Our observations suggest that initially FtsZ localizes in a helical pattern, with movement of FtsZ within this structure occurring along the entire length of the cell. Next, movement of FtsZ in a helical-like pattern is restricted to a central region of the cell. Finally the FtsZ ring forms precisely at midcell. We further show that another division protein, FtsA, shown to interact with FtsZ prior to Z ring formation in B. subtilis, also localizes to similar helical patterns in vegetatively growing cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / cytology*
  • Bacillus subtilis / growth & development*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism*
  • Cytokinesis*
  • Cytoskeletal Proteins / chemistry*
  • Cytoskeletal Proteins / metabolism*
  • Microbial Viability
  • Models, Biological
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Transport
  • Recombinant Fusion Proteins / metabolism
  • Spores, Bacterial / cytology
  • Time Factors


  • Bacterial Proteins
  • Cytoskeletal Proteins
  • FtsA protein, Bacteria
  • FtsZ protein, Bacteria
  • Recombinant Fusion Proteins