FtsZ placement in nucleoid-free bacteria

PLoS One. 2014 Mar 17;9(3):e91984. doi: 10.1371/journal.pone.0091984. eCollection 2014.

Abstract

We describe the placement of the cytoplasmic FtsZ protein, an essential component of the division septum, in nucleoid-free Escherichia coli maxicells. The absence of the nucleoid is accompanied in maxicells by degradation of the SlmA protein. This protein, together with the nucleoid, prevents the placement of the septum in the regions occupied by the chromosome by a mechanism called nucleoid occlusion (NO). A second septum placement mechanism, the MinCDE system (Min) involving a pole-to-pole oscillation of three proteins, nonetheless remains active in maxicells. Both Min and NO act on the polymerization of FtsZ, preventing its assembly into an FtsZ-ring except at midcell. Our results show that even in the total absence of NO, Min oscillations can direct placement of FtsZ in maxicells. Deletion of the FtsZ carboxyl terminal domain (FtsZ*), a central hub that receives signals from a variety of proteins including MinC, FtsA and ZipA, produces a Min-insensitive form of FtsZ unable to interact with the membrane-anchoring FtsA and ZipA proteins. This protein produces a totally disorganized pattern of FtsZ localization inside the maxicell cytoplasm. In contrast, FtsZ*-VM, an artificially cytoplasmic membrane-anchored variant of FtsZ*, forms helical or repetitive ring structures distributed along the entire length of maxicells even in the absence of NO. These results show that membrane anchoring is needed to organize FtsZ into rings and underscore the role of the C-terminal hub of FtsZ for their correct placement.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cell Division
  • Cytoplasm / metabolism
  • Cytoskeletal Proteins / chemistry
  • Cytoskeletal Proteins / genetics*
  • Cytoskeletal Proteins / metabolism*
  • Escherichia coli / genetics*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Nitric Oxide / metabolism
  • Protein Interaction Domains and Motifs
  • Protein Transport
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • Bacterial Proteins
  • Carrier Proteins
  • Cytoskeletal Proteins
  • Escherichia coli Proteins
  • FtsZ protein, Bacteria
  • Recombinant Fusion Proteins
  • SlmA protein, E coli
  • Nitric Oxide

Grants and funding

This work was supported through grants from European Commission HEALTH-F3-2009-223431 (DIVINOCELL) (http://ec.europa.eu/research/index.cfm) to MV, Ministerio de Ciencia e Innovación BIO2011-28941-C03-01 (http://www.idi.mineco.gob.es/) to MV, and Human Frontier Science Program RGP0050/2010 (http://www.hfsp.org/) to MV and WM. PN acknowledges a fellowship from Programa Juan de la Cierva Ministerio de Educación y Ciencia. MP acknowledges a fellowship from Programa de Formación de Personal Investigador Ministerio de Educación y Ciencia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.