This Article Full Text Full Text (PDF) Supplemental material 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 Keeney, K. Articles by O'Riordan, M. Search for Related Content PubMed PubMed Citation Articles by Keeney, K. Articles by O'Riordan, M.

 Previous Article  |  Next Article 

Journal of Bacteriology, April 2009, p. 2187-2196, Vol. 191, No. 7
0021-9193/09/$08.00+0     doi:10.1128/JB.01179-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Generation of Branched-Chain Fatty Acids through Lipoate-Dependent Metabolism Facilitates Intracellular Growth of Listeria monocytogenes ^,

Kristie Keeney,¹ Lisa Colosi,^2, Walter Weber,² and Mary O'Riordan^1*

Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109,¹ Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109²

Received 20 August 2008/ Accepted 21 January 2009

The gram-positive bacterial pathogen Listeria monocytogenes has evolved mechanisms to rapidly replicate in the host cytosol, implying efficient utilization of host-derived nutrients. However, the contribution of host nutrient scavenging versus that of bacterial biosynthesis toward rapid intracellular growth remains unclear. Nutrients that contribute to growth of L. monocytogenes include branched-chain fatty acids (BCFAs), amino acids, and other metabolic intermediates generated from acyl-coenzyme A, which is synthesized using lipoylated metabolic enzyme complexes. To characterize which biosynthetic pathways support replication of L. monocytogenes inside the host cytosol, we impaired lipoate-dependent metabolism by disrupting two lipoate ligase genes that are responsible for bacterial protein lipoylation. Interrupting lipoate-dependent metabolism modestly impaired replication in rich broth medium but strongly inhibited growth in defined medium and host cells and impaired the generation of BCFAs. Addition of short BCFAs and amino acids restored growth of the A1A2-deficient (A1A2^–) mutant in minimal medium, implying that lipoate-dependent metabolism generates amino acids and BCFAs. BCFAs alone rescued intracellular growth and spread in L2 fibroblasts of the A1A2^– mutant. Lipoate-dependent metabolism was also required in vivo, as a wild-type strain robustly outcompeted the lipoylation-deficient mutant in a murine model of listeriosis. The results of this study suggest that lipoate-dependent metabolism contributes to both amino acid and BCFA biosynthesis and that BCFA biosynthesis is preferentially required for intracellular growth of L. monocytogenes.

---

* Corresponding author. Mailing address: University of Michigan, Department of Microbiology and Immunology, 1150 W. Medical Center Drive, Ann Arbor, MI 48109. Phone: (734) 615-4289. Fax: (734) 764-3562. E-mail: oriordan{at}umich.edu

Published ahead of print on 30 January 2009.

Supplemental material for this article may be found at http://jb.asm.org/.

Present address: University of Virginia, Department of Civil and Environmental Engineering, P.O. Box 400742, Charlottesville, VA 22904-4742.

---

Journal of Bacteriology, April 2009, p. 2187-2196, Vol. 191, No. 7
0021-9193/09/$08.00+0     doi:10.1128/JB.01179-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Martin, N., Lombardia, E., Altabe, S. G., de Mendoza, D., Mansilla, M. C. (2009). A lipA (yutB) Mutant, Encoding Lipoic Acid Synthase, Provides Insight into the Interplay between Branched-Chain and Unsaturated Fatty Acid Biosynthesis in Bacillus subtilis. J. Bacteriol. 191: 7447-7455 [Abstract] [Full Text]