Document Detail


Escherichia coli cyclomodulin Cif induces G2 arrest of the host cell cycle without activation of the DNA-damage checkpoint-signalling pathway.
MedLine Citation:
PMID:  16848790     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The cycle inhibiting factor (Cif) belongs to a family of bacterial toxins and effector proteins, the cyclomodulins, that deregulate the host cell cycle. Upon injection into HeLa cells by the enteropathogenic Escherichia coli (EPEC) type III secretion system, Cif induces a cytopathic effect characterized by the recruitment of focal adhesion plates and the formation of stress fibres, an irreversible cell cycle arrest at the G(2)/M transition, and sustained inhibitory phosphorylation of mitosis inducer, CDK1. Here, we report that the reference typical EPEC strain B171 produces a functional Cif and that lipid-mediated delivery of purified Cif into HeLa cells induces cell cycle arrest and actin stress fibres, implying that Cif is necessary and sufficient for these effects. EPEC infection of intestinal epithelial cells (Caco-2, IEC-6) also induces cell cycle arrest and CDK1 inhibition. The effect of Cif is strikingly similar to that of cytolethal distending toxin (CDT), which inhibits the G(2)/M transition by activating the DNA-damage checkpoint pathway. However, in contrast to CDT, Cif does not cause phosphorylation of histone H2AX, which is associated with DNA double-stranded breaks. Following EPEC infection, the checkpoint effectors ATM/ATR, Chk1 and Chk2 are not activated, the levels of the CDK-activating phosphatases Cdc25B and Cdc25C are not affected, and Cdc25C is not sequestered in host cell cytoplasm. Hence, Cif activates a DNA damage-independent signalling pathway that leads to inhibition of the G(2)/M transition.
Authors:
Frédéric Taieb; Jean-Philippe Nougayrède; Claude Watrin; Ascel Samba-Louaka; Eric Oswald
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-07-11
Journal Detail:
Title:  Cellular microbiology     Volume:  8     ISSN:  1462-5814     ISO Abbreviation:  Cell. Microbiol.     Publication Date:  2006 Dec 
Date Detail:
Created Date:  2006-11-09     Completed Date:  2007-01-25     Revised Date:  2011-11-02    
Medline Journal Info:
Nlm Unique ID:  100883691     Medline TA:  Cell Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1910-21     Citation Subset:  IM    
Affiliation:
UMR 1225, IHAP, INRA-ENVT, 23 Chemin des Capelles, BP 87614, 31000 Toulouse, France. f.taieb@envt.fr
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MeSH Terms
Descriptor/Qualifier:
Animals
Bacterial Toxins / metabolism
Caco-2 Cells
Cell Cycle*
Cell Cycle Proteins / metabolism
DNA Breaks, Double-Stranded
DNA Damage
Escherichia coli / metabolism,  pathogenicity*
Escherichia coli Proteins / metabolism*
G2 Phase
Hela Cells
Humans
Intestinal Mucosa / microbiology*
Protein Kinases / metabolism
Protein-Serine-Threonine Kinases / metabolism
Rabbits
Rats
Signal Transduction
cdc25 Phosphatases / metabolism
Chemical
Reg. No./Substance:
0/Bacterial Toxins; 0/Cell Cycle Proteins; 0/Cif protein, E coli; 0/Escherichia coli Proteins; 0/cytolethal distending toxin; EC 2.7.-/Protein Kinases; EC 2.7.1.11/checkpoint kinase 2; EC 2.7.11.1/Checkpoint kinase 1; EC 2.7.11.1/Protein-Serine-Threonine Kinases; EC 3.1.3.16/CDC25B protein, human; EC 3.1.3.48/CDC25C protein, human; EC 3.1.3.48/cdc25 Phosphatases

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