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 Google Scholar
Google Scholar
Right arrow Articles by Aly, K. A.
Right arrow Articles by Baron, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aly, K. A.
Right arrow Articles by Baron, C.

 Previous Article  |  Next Article 

Journal of Bacteriology, March 2008, p. 1595-1604, Vol. 190, No. 5
0021-9193/08/$08.00+0     doi:10.1128/JB.01718-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

The Type IV Secretion System Component VirB5 Binds to the trans-Zeatin Biosynthetic Enzyme Tzs and Enables Its Translocation to the Cell Surface of Agrobacterium tumefaciens{triangledown}

Khaled Ahmed Aly,1,{dagger} Lilian Krall,2,{dagger},{ddagger} Friedrich Lottspeich,3 and Christian Baron1,2*

McMaster University, Department of Biology, 1280 Main St. West, Hamilton, Ontario L8S 4K1, Canada,1 Ludwig-Maximilians-Universität, Department Biologie I, Bereich Mikrobiologie, Maria-Ward-Str. 1a, D-80638 München, Germany,2 Max-Planck Institute of Biochemistry, Protein Analysis, Am Klopferspitz 18, D-82152 Martinsried, Germany3

Received 26 October 2007/ Accepted 14 December 2007

VirB5 is a minor component of the extracellular T pilus determined by the Agrobacterium tumefaciens type IV secretion system. To identify proteins that interact with VirB5 during the pilus assembly process, we purified VirB5 as a recombinant fusion protein and, by using a gel overlay assay, we detected a 26-kDa interacting protein in Agrobacterium cell lysates. The VirB5-binding protein was purified from A. tumefaciens and identified as the cytokinin biosynthetic enzyme Tzs. The VirB5-Tzs interaction was confirmed using pulldown assays with purified proteins and the yeast two-hybrid system. An analysis of the subcellular localization in A. tumefaciens showed that Tzs was present in the soluble as well as the membrane fraction. Tzs was extracted from the membranes with the mild detergent dodecyl-β-D-maltoside in complexes of different molecular masses, and this association was strongly reduced in the absence of VirB5. Using immunoelectron microscopy, we also detected Tzs on the Agrobacterium cell surface. A functional type IV secretion system was required for efficient translocation to the surface, but Tzs was not secreted into the cell supernatant. The fact that Tzs localizes on the cell surface suggests that it may contribute to the interaction of Agrobacterium with plants.

* Corresponding author. Mailing address: McMaster University, Department of Biology, 1280 Main St. West, Hamilton, Ontario L8S 4K1, Canada. Phone: (905) 525 9140, ext. 26692. Fax: (905) 522-6066. E-mail: baronc{at}mcmaster.ca

{triangledown} Published ahead of print on 28 December 2007.

{dagger} The first two authors contributed equally to this study.

{ddagger} Present address: Geltingerstr. 4a, D-82515 Wolfratshausen, Germany.

Journal of Bacteriology, March 2008, p. 1595-1604, Vol. 190, No. 5
0021-9193/08/$08.00+0     doi:10.1128/JB.01718-07
Copyright © 2008, 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»