ZapA and ZapB form an FtsZ-independent structure at midcell

Mol Microbiol. 2017 May;104(4):652-663. doi: 10.1111/mmi.13655. Epub 2017 Mar 26.


Cell division in Escherichia coli begins with the polymerization of FtsZ into a ring-like structure, the Z-ring, at midcell. All other division proteins are thought to require the Z-ring for recruitment to the future division site. Here, it is reported that the Z-ring associated proteins ZapA and ZapB form FtsZ-independent structures at midcell. Upon Z-ring disruption by the FtsZ polymerization antagonist SulA, ZapA remained at midcell as a cloud-like accumulation. Using ZapA(N60Y), a variant defective for interaction with FtsZ, it was established that these ZapA structures form without a connection to the Z-ring. Furthermore, midcell accumulations of GFP-ZapA(N60Y) often preceded Z-rings at midcell and required ZapB to assemble, suggesting that ZapB polymers form the foundation of these structures. In the absence of MatP, a DNA-binding protein that links ZapB to the chromosomal terminus region, cloud-like ZapA structures still formed but failed to track with the chromosome terminus and did not consistently precede FtsZ at midcell. Taken together, the results suggest that FtsZ-independent structures of ZapA-ZapB provide additional positional cues for Z-ring formation and may help coordinate its assembly with chromosome replication and segregation.

MeSH terms

  • Bacterial Proteins / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Division / genetics
  • Cytoskeletal Proteins / metabolism
  • DNA-Binding Proteins / metabolism
  • Escherichia coli / genetics
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Polymerization
  • Protein Binding


  • Bacterial Proteins
  • Carrier Proteins
  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • ZapA protein, E coli
  • ZapB protein, E coli