Document Detail


Intoxication of epithelial cells by plasmid-encoded toxin requires clathrin-mediated endocytosis.
MedLine Citation:
PMID:  17768228     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It has been shown that the autotransporter plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli (EAEC) produces cytotoxic and enterotoxic effects. Both effects can be explained by the proteolytic activity of Pet on its intracellular target alpha-fodrin (alphaII spectrin). In addition, Pet cytotoxicity and enterotoxicity depend on Pet serine protease activity, and on its internalization into epithelial cells. However, the mechanisms of Pet uptake by epithelial cells are unknown. Here, we show that Pet interacts with the plasma membrane of epithelial cells, and afterwards is detected inside the cells. Furthermore, Pet was internalized via clathrin-mediated endocytosis, since its internalization was inhibited by monodansylcadaverine and sucrose, but not by filipin or methyl-beta-cyclodextrin, which are drugs that interfere with protein entry via a clathrin-independent pathway. Additionally, Pet was immunoprecipitated by anti-clathrin antibodies, but not by anti-caveolin antibodies. Moreover, small interfering RNA (siRNA), designed to knock out clathrin gene expression in HEp-2 cells, prevented Pet internalization, and thereby the Pet-induced cytotoxic effect. However, the use of siRNA to knock out caveolin expression had no effect on Pet internalization, and the cytotoxic effect was clearly observed. Together, these data indicate that Pet secreted by EAEC binds to the cell surface via an unknown receptor, to be taken up by clathrin-mediated endocytosis, and exert its toxic effect in the cytoplasm.
Authors:
Fernando Navarro-García; Adrián Canizalez-Roman; Jorge E Vidal; Ma Isabel Salazar
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  153     ISSN:  1350-0872     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-04     Completed Date:  2007-11-26     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  England    
Other Details:
Languages:  eng     Pagination:  2828-38     Citation Subset:  IM    
Affiliation:
Department of Cell Biology, Centro de Investigación y de Estudios Avanzados (Cinvestav-Zacatenco), Ap. Postal 14-740, 07000 México, DF, Mexico. fnavarro@cell.cinvestav.mx
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MeSH Terms
Descriptor/Qualifier:
Bacterial Toxins / chemistry,  genetics,  metabolism,  toxicity*
Cell Line
Cell Membrane / metabolism
Clathrin / pharmacology*
Clathrin-Coated Vesicles / metabolism
Endocytosis / drug effects*,  physiology
Enterotoxins / chemistry,  genetics,  metabolism,  toxicity*
Epithelial Cells / metabolism*
Escherichia coli / genetics,  metabolism,  pathogenicity*
Escherichia coli Proteins / chemistry,  genetics,  metabolism,  toxicity*
Humans
RNA, Small Interfering / genetics,  metabolism
Serine Endopeptidases
Chemical
Reg. No./Substance:
0/Bacterial Toxins; 0/Clathrin; 0/Enterotoxins; 0/Escherichia coli Proteins; 0/RNA, Small Interfering; 0/heat-labile enterotoxin, E coli; EC 3.4.21.-/Pet protein, E coli; EC 3.4.21.-/Serine Endopeptidases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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