Document Detail

TyeA of Yersinia pseudotuberculosis is involved in regulation of Yop expression and is required for polarized translocation of Yop effectors.
MedLine Citation:
PMID:  12614462     Owner:  NLM     Status:  MEDLINE    
Type III secretion-dependent translocation of Yop (Yersinia outer proteins) effector proteins into host cells is an essential virulence mechanism common to the pathogenic Yersinia species. One unique feature of this mechanism is the polarized secretion of Yops, i.e. Yops are only secreted at the site of contact with the host cell and not to the surrounding medium. In vitro, secretion occurs in Ca2+-depleted media, a condition believed to somehow mimic cell contact. Three proteins, YopN, LcrG and TyeA have been suggested to control secretion and mutating any of these genes results in constitutive secretion. In addition, in Y. enterocolitica TyeA has been implied to be specifically required for delivery of a subset of Yop effectors into infected cells. In this work we have investigated the role of TyeA in secretion and translocation of Yop effectors by Y. pseudotuberculosis. An in frame deletion mutant of tyeA was found to be temperature-sensitive for growth and this phenotype correlated to a lowered expression of the negative regulatory element LcrQ. In medium containing Ca2+, Yop expression was somewhat elevated compared to the wild-type strain and low levels of Yop secretion was also seen. Somewhat surprisingly, expression and secretion of Yops was lower than for the wild-type strain when the tyeA mutant was grown in Ca2+-depleted medium. Translocation of YopE, YopH, YopJ and YopM into infected HeLa cells was significantly lower in comparison with the isogenic wild-type strain and Yop proteins could also be recovered in the tissue culture medium. This indicated that the tyeA mutant had lost the ability to translocate Yop proteins by a polarized mechanism. In order to exclude that the defect in translocation seen in the tyeA mutant was a result of lowered expression/secretion of Yops, a double lcrQ/tyeA mutant was constructed. This strain was de-repressed for Yop expression and secretion but was still impaired for translocation of both YopE and YopM. In addition, the low level of YopE translocation in the tyeA mutant was independent of the YopE chaperone YerA/SycE. TyeA was found to localize to the cytoplasm of the bacterium and we were unable to find any evidence that TyeA was secreted or surface located. From our studies in Y. pseudotuberculosis we conclude that TyeA is involved in regulation of Yop expression and required for polarized delivery of Yop effectors in general and is not as suggested in Y. enterocolitica directly required for translocation of a subset of Yop effectors.
Lena Sundberg; Ake Forsberg
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cellular microbiology     Volume:  5     ISSN:  1462-5814     ISO Abbreviation:  Cell. Microbiol.     Publication Date:  2003 Mar 
Date Detail:
Created Date:  2003-03-04     Completed Date:  2003-04-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100883691     Medline TA:  Cell Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  187-202     Citation Subset:  IM    
Department of Medical Countermeasures, Division of NBC-Defence, Swedish Defence Research Agency, S-901 82 Umeå, Sweden.
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MeSH Terms
Bacterial Outer Membrane Proteins / metabolism*,  pharmacology*,  secretion
Bacterial Proteins / metabolism
Biological Transport
Carrier Proteins / analysis,  genetics,  metabolism,  pharmacology*,  physiology,  secretion
Cell Polarity
Gene Expression Regulation, Bacterial
Hela Cells
Molecular Chaperones / physiology
Protein Transport
Yersinia pseudotuberculosis / cytology,  metabolism,  pathogenicity*
Reg. No./Substance:
0/Bacterial Outer Membrane Proteins; 0/Bacterial Proteins; 0/Carrier Proteins; 0/Molecular Chaperones; 0/TyeA protein, Yersinia; 0/YopP protein, Yersinia; 0/yopE protein, Yersinia; 124893-29-4/yopM protein, Yersinia

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