This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rossier, O. Articles by Cianciotto, N. P. Search for Related Content PubMed PubMed Citation Articles by Rossier, O. Articles by Cianciotto, N. P.

 Previous Article  |  Next Article 

Infection and Immunity, April 2005, p. 2020-2032, Vol. 73, No. 4
0019-9567/05/$08.00+0     doi:10.1128/IAI.73.4.2020-2032.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

The Legionella pneumophila tatB Gene Facilitates Secretion of Phospholipase C, Growth under Iron-Limiting Conditions, and Intracellular Infection

Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois

Received 9 February 2004/ Returned for modification 10 March 2004/ Accepted 22 December 2004

Our previous mutational analysis of Legionella pneumophila demonstrated a role for type II protein (Lsp) secretion and iron acquisition in intracellular infection and virulence. In gram-negative bacteria, the twin-arginine translocation (Tat) pathway is involved in secretion of proteins, including components of respiratory complexes, across the inner membrane to the periplasm. To assess the significance of Tat for L. pneumophila, tatB mutants were characterized. The mutants exhibited normal growth in standard media but grew slowly under low-iron conditions. They were also impaired in the Nadi assay, indicating that the function of cytochrome c oxidase is influenced by tatB. Consistent with this observation, a subunit of the cytochrome c reductase was shown to be a Tat substrate. Supernatants of the tatB mutants showed a 30% reduction in phospholipase C activity while maintaining normal levels of other Lsp secreted activities. When tested for infection of U937 macrophages, the tatB mutants showed a 10-fold reduction in growth. Double mutants lacking tatB and Lsp secretion were even more defective, suggesting tatB has an intracellular role that is independent of Lsp. tatB mutants were also impaired 20-fold in Hartmannella vermiformis amoebae cultured in the presence of an iron chelator. All mutant phenotypes were complemented by reintroduction of an intact tatB. Thus, L. pneumophila tatB plays a role in the formation of a respiratory complex, growth under low-iron conditions, the secretion of a phospholipase C activity, and intracellular infection.

Editor: D. L. Burns

This article has been cited by other articles:

• McDonough, J. A., McCann, J. R., Tekippe, E. M., Silverman, J. S., Rigel, N. W., Braunstein, M. (2008). Identification of Functional Tat Signal Sequences in Mycobacterium tuberculosis Proteins. J. Bacteriol. 190: 6428-6438 [Abstract] [Full Text]  
• Soderberg, M. A., Cianciotto, N. P. (2008). A Legionella pneumophila Peptidyl-Prolyl cis-trans Isomerase Present in Culture Supernatants Is Necessary for Optimal Growth at Low Temperatures. Appl. Environ. Microbiol. 74: 1634-1638 [Abstract] [Full Text]  
• Rossier, O., Dao, J., Cianciotto, N. P. (2008). The Type II Secretion System of Legionella pneumophila Elaborates Two Aminopeptidases, as Well as a Metalloprotease That Contributes to Differential Infection among Protozoan Hosts. Appl. Environ. Microbiol. 74: 753-761 [Abstract] [Full Text]  
• De Buck, E., Anne, J., Lammertyn, E. (2007). The role of protein secretion systems in the virulence of the intracellular pathogen Legionella pneumophila. Microbiology 153: 3948-3953 [Abstract] [Full Text]  
• Chatfield, C. H., Cianciotto, N. P. (2007). The Secreted Pyomelanin Pigment of Legionella pneumophila Confers Ferric Reductase Activity. Infect. Immun. 75: 4062-4070 [Abstract] [Full Text]  
• DebRoy, S., Dao, J., Soderberg, M., Rossier, O., Cianciotto, N. P. (2006). Legionella pneumophila type II secretome reveals unique exoproteins and a chitinase that promotes bacterial persistence in the lung. Proc. Natl. Acad. Sci. USA 103: 19146-19151 [Abstract] [Full Text]  
• DebRoy, S., Aragon, V., Kurtz, S., Cianciotto, N. P. (2006). Legionella pneumophila Mip, a Surface-Exposed Peptidylproline cis-trans-Isomerase, Promotes the Presence of Phospholipase C-Like Activity in Culture Supernatants. Infect. Immun. 74: 5152-5160 [Abstract] [Full Text]  
• Lavander, M., Ericsson, S. K., Broms, J. E., Forsberg, A. (2006). The Twin Arginine Translocation System Is Essential for Virulence of Yersinia pseudotuberculosis. Infect. Immun. 74: 1768-1776 [Abstract] [Full Text]  
• Posey, J. E., Shinnick, T. M., Quinn, F. D. (2006). Characterization of the Twin-Arginine Translocase Secretion System of Mycobacterium smegmatis. J. Bacteriol. 188: 1332-1340 [Abstract] [Full Text]  
• McDonough, J. A., Hacker, K. E., Flores, A. R., Pavelka, M. S. Jr, Braunstein, M. (2005). The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial {beta}-Lactamases. J. Bacteriol. 187: 7667-7679 [Abstract] [Full Text]