A novel membrane-bound toxin for cell division, CptA (YgfX), inhibits polymerization of cytoskeleton proteins, FtsZ and MreB, in Escherichia coli

Hisako Masuda, Qian Tan, Naoki Awano, Yoshihiro Yamaguchi, Masayori Inouye

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

Nearly all free-living bacteria carry toxin-antitoxin (TA) systems on their genomes, through which cell growth and death are regulated. Toxins target a variety of essential cellular functions, including DNA replication, translation, and cell division. Here, we identified a novel toxin, YgfX, on the Escherichia coli genome. The toxin, consisting of 135 residues, is composed of the N-terminal membrane domain, which encompasses two transmembrane segments, and the C-terminal cytoplasmic domain. Upon YgfX expression, the cells were initially elongated and then the middle portion of the cells became inflated to form a lemon shape. YgfX was found to interact with MreB and FtsZ, two essential cytoskeletal proteins in E. coli. The cytoplasmic domain [YgfX(C)] was found to be responsible for the YgfX toxicity, as purified YgfX(C) was found to block the polymerization of FtsZ and MreB in vitro. YgfY, located immediately upstream of YgfX, was shown to be the cognate antitoxin; notably, YgfX is the first membrane-associating toxin in bacterial TA systems. We propose to rename the toxin and the antitoxin as CptA and CptB (for Cytoskeleton Polymerization inhibiting Toxin), respectively.

Original languageEnglish (US)
Pages (from-to)174-181
Number of pages8
JournalFEMS Microbiology Letters
Volume328
Issue number2
DOIs
StatePublished - Mar 2012

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology
  • Genetics

Keywords

  • Cell morphology
  • Growth inhibition
  • Toxin-antitoxin

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