Article thumbnail

Toxin on a stick: Modular CDI toxin delivery systems play roles in bacterial competition

By Stephanie K Aoki, Stephen J Poole, Christopher S Hayes and David A Low

Abstract

Contact-dependent growth inhibition (CDI) is the first contact-dependent competition system identified in bacteria. CDI is mediated by the CdiA/CdiB two-partner secretion system, and the BamA outer membrane protein serves as the CDI receptor on target cells. A small immunity protein, CdiI, is required to protect inhibitor cells from their own CDI system. Recent results from our group show that CDI systems are present in a number of important gram-negative plant and animal pathogens. The C-terminal region of CdiA (CdiA-CT) is polymorphic and contains growth inhibitory activity. The CdiA-CT from uropathogenic Escherichia coli 536 is a tRNase whereas a CdiA-CT from Dickeya dadantii 3937 has DNase activity. Accordingly, these bacteria contain distinct CdiI proteins that specifically bind and inactivate cognate CdiA-CT. Remarkably, CdiA-CTs are modular: one CdiA “stick” can deliver different CdiA-CT toxins. We discuss these findings as well as results showing that CDI plays an important role in intra-strain bacterial competition in the natural world. A detailed mechanistic understanding of CDI could facilitate development of probiotics and antimicrobials that target specific pathogens

Topics: Article Addendum
Publisher: Landes Bioscience
OAI identifier: oai:pubmedcentral.nih.gov:3173679
Provided by: PubMed Central
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://www.pubmedcentral.nih.g... (external link)

  • To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.

    Suggested articles