This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Björnfot, A.-C.
Right arrow Articles by Wolf-Watz, H.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Björnfot, A.-C.
Right arrow Articles by Wolf-Watz, H.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2009, p. 4259-4267, Vol. 191, No. 13
0021-9193/09/$08.00+0     doi:10.1128/JB.01730-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Autoproteolysis of YscU of Yersinia pseudotuberculosis Is Important for Regulation of Expression and Secretion of Yop Proteins {triangledown}

Ann-Catrin Björnfot,1 Moa Lavander,2 Åke Forsberg,1,3 and Hans Wolf-Watz1*

Department of Molecular Biology and The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden,1 Department of Clinical Microbiology, Division of Infectious Diseases, Umeå University, SE-901 85 Umeå, Sweden,2 Department of Medical Countermeasures, Division of NBC Defense, Swedish Defense Research Agency, SE-901 82 Umeå, Sweden3

Received 10 December 2008/ Accepted 15 April 2009

YscU of Yersinia can be autoproteolysed to generate a 10-kDa C-terminal polypeptide designated YscUCC. Autoproteolysis occurs at the conserved N{downarrow}PTH motif of YscU. The specific in-cis-generated point mutants N263A and P264A were found to be defective in proteolysis. Both mutants expressed and secreted Yop proteins (Yops) in calcium-containing medium (+Ca2+ conditions) and calcium-depleted medium (–Ca2+ conditions). The level of Yop and LcrV secretion by the N263A mutant was about 20% that of the wild-type strain, but there was no significant difference in the ratio of the different secreted Yops, including LcrV. The N263A mutant secreted LcrQ regardless of the calcium concentration in the medium, corroborating the observation that Yops were expressed and secreted in Ca2+-containing medium by the mutant. YscF, the type III secretion system (T3SS) needle protein, was secreted at elevated levels by the mutant compared to the wild type when bacteria were grown under +Ca2+ conditions. YscF secretion was induced in the mutant, as well as in the wild type, when the bacteria were incubated under –Ca2+ conditions, although the mutant secreted smaller amounts of YscF. The N263A mutant was cytotoxic for HeLa cells, demonstrating that the T3SS-mediated delivery of effectors was functional. We suggest that YscU blocks Yop release and that autoproteolysis is required to relieve this block.

* Corresponding author. Mailing address: Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden. Phone: 46-(0)90-7856753. Fax: 46-(0)90-772630. E-mail: hans.wolf-watz{at}molbiol.umu.se

{triangledown} Published ahead of print on 24 April 2009.

Journal of Bacteriology, July 2009, p. 4259-4267, Vol. 191, No. 13
0021-9193/09/$08.00+0     doi:10.1128/JB.01730-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»