JB
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 Bronstein, P. A.
Right arrow Articles by Miller, S. I.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bronstein, P. A.
Right arrow Articles by Miller, S. I.

Journal of Bacteriology, December 2000, p. 6638-6644, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.

InvB Is a Type III Secretion Chaperone Specific for SspA

Philip A. Bronstein,1 Edward A. Miao,1 and Samuel I. Miller1,2,*

Department of Microbiology1 and Department of Medicine,2 University of Washington, Seattle, Washington 98195

Received 27 June 2000/Accepted 18 September 2000

A wide variety of gram-negative bacteria utilize a specialized apparatus called the type III secretion system (TTSS) to translocate virulence factors directly into the cytoplasm of eukaryotic cells. These translocated effectors contribute to the pathogen's ability to infect and replicate within plant and animal hosts. The amino terminus of effector proteins contains sequences that are necessary and sufficient for both secretion and translocation by TTSS. Portions of these sequences contain binding sites for type III chaperones, which facilitate efficient secretion and translocation of specific effectors through TTSS. In this study, we have utilized the yeast two-hybrid assay to identify protein-protein interactions between effector and chaperone proteins encoded within Salmonella pathogenicity island 1 (SPI-1). Several interactions were identified including a novel interaction between the effector protein, SspA (SipA), and a putative chaperone, InvB. InvB was demonstrated to bind to the amino terminus of SspA in the bacterial cytoplasm. Furthermore, InvB acts as a type III chaperone for the efficient secretion and translocation of SspA by SPI-1. InvB also permitted translocation of SspA through the SPI-2 TTSS, indicating that it is an important regulator in the recognition of SspA as a target of TTSS. Finally, it was determined that InvB does not alter the transcription of sspA but that its absence results in reduced SspA protein levels in Salmonella enterica serovar Typhimurium.

* Corresponding author. Mailing address: Departments of Medicine and Microbiology, University of Washington, Health Sciences Building, Box 357710, Seattle, WA 98195. Phone: (206) 616-5107. Fax: (206) 616-4295. E-mail: millersi{at}u.washington.edu.

Journal of Bacteriology, December 2000, p. 6638-6644, Vol. 182, No. 23
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 2000 by the American Society for Microbiology. All rights reserved.