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
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lorenz, C.
Right arrow Articles by Büttner, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lorenz, C.
Right arrow Articles by Büttner, D.

 Previous Article  |  Next Article 

Journal of Bacteriology, March 2009, p. 1414-1428, Vol. 191, No. 5
0021-9193/09/$08.00+0     doi:10.1128/JB.01446-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Functional Characterization of the Type III Secretion ATPase HrcN from the Plant Pathogen Xanthomonas campestris pv. vesicatoria{triangledown}

Christian Lorenz and Daniela Büttner*

Institut für Biologie, Bereich Genetik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale), Germany

Received 15 October 2008/ Accepted 16 December 2008

Many gram-negative plant and animal pathogenic bacteria employ a type III secretion (T3S) system to inject effector proteins into the cytosol of eukaryotic host cells. The membrane-spanning T3S apparatus is associated with an ATPase that presumably provides the energy for the secretion process. Here, we describe the role of the predicted ATPase HrcN from the plant pathogenic bacterium Xanthomonas campestris pathovar vesicatoria. We show that HrcN hydrolyzes ATP in vitro and is essential for T3S and bacterial pathogenicity. Stability of HrcN in X. campestris pv. vesicatoria depends on the conserved HrcL protein, which interacts with HrcN in vitro and in vivo. Both HrcN and HrcL bind to the inner membrane protein HrcU and specifically localize to the bacterial membranes under T3S-permissive conditions. Protein-protein interaction studies revealed that HrcN also interacts with the T3S substrate specificity switch protein HpaC and the global T3S chaperone HpaB, which promotes secretion of multiple effector proteins. Using an in vitro chaperone release assay, we demonstrate that HrcN dissociates a complex between HpaB and the effector protein XopF1 in an ATP-dependent manner, suggesting that HrcN is involved in the release of HpaB-bound effectors. Effector release depends on a conserved glycine residue in the HrcN phosphate-binding loop, which is crucial for enzymatic activity and protein function during T3S. There is no experimental evidence that T3S can occur in the absence of the ATPase, in contrast to recent findings reported for animal pathogenic bacteria.

* Corresponding author. Mailing address: Institut für Biologie, Bereich Genetik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale), Germany. Phone: (49) 345 5526293. Fax: (49) 345 5527151. E-mail: daniela.buettner{at}genetik.uni-halle.de

{triangledown} Published ahead of print on 29 December 2008.

Journal of Bacteriology, March 2009, p. 1414-1428, Vol. 191, No. 5
0021-9193/09/$08.00+0     doi:10.1128/JB.01446-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Buttner, D., He, S. Y. (2009). Type III Protein Secretion in Plant Pathogenic Bacteria. Plant Physiol. 150: 1656-1664 [Full Text]  


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