IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
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 Schuch, R.
Right arrow Articles by Maurelli, A. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Schuch, R.
Right arrow Articles by Maurelli, A. T.

 Previous Article  |  Next Article 

Infection and Immunity, April 2001, p. 2180-2189, Vol. 69, No. 4
0019-9567/01/$04.00+0   DOI: 10.1128/IAI.69.4.2180-2189.2001

Spa33, a Cell Surface-Associated Subunit of the Mxi-Spa Type III Secretory Pathway of Shigella flexneri, Regulates Ipa Protein Traffic

Raymond Schuch and Anthony T. Maurelli*

Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814

Received 11 August 2000/Returned for modification 7 November 2000/Accepted 22 December 2000

The Mxi-Spa type III secretion system of Shigella flexneri directs the host cell contact-induced secretion of a set of invasins, referred to as Ipas. In this study, we examined the role of Spa33 in Ipa secretion. A spa33-null mutant was both noninvasive and unable to translocate the Ipas from inner membrane to outer membrane (OM) positions of the Mxi-Spa transmembrane channel. Spa33 was found to be a Mxi-Spa substrate that is translocated to the bacterial cell surface upon the induction of Ipa secretion. This mobility may serve to drive Ipa translocation within Mxi-Spa toward OM positions. Consistent with a second distinct role in regulating Ipa traffic, the overexpression of Spa33 also blocked Ipa secretion and resulted in Ipa accumulation at the OM. Co-overexpression of Spa33 and another OM-associated element, Spa32, did not disrupt Ipa secretion, suggesting an interaction between the two proteins and an effect on the mechanism which serves to regulate Ipa release from the OM. These findings indicate that Spa33 is a mobile element within Mxi-Spa, which is required to control Ipa translocation into and out of OM positions of the secretory structure.

* Corresponding author. Mailing address: Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD 20814-4799. Phone: (301) 295-3415. Fax: (301) 295-1545. E-mail: amaurelli{at}usuhs.mil.

Infection and Immunity, April 2001, p. 2180-2189, Vol. 69, No. 4
0019-9567/01/$04.00+0   DOI: 10.1128/IAI.69.4.2180-2189.2001


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2001 by the American Society for Microbiology. All rights reserved.