Mycobacterial Esx-3 is required for mycobactin-mediated iron acquisition |
| |
| Authors: | M. Sloan Siegrist Meera Unnikrishnan Matthew J. McConnell Mark Borowsky Tan-Yun Cheng Noman Siddiqi Sarah M. Fortune D. Branch Moody Eric J. Rubin |
| |
| Affiliation: | aDepartment of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115; ;bDivision of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women''s Hospital, Harvard Medical School, Boston, MA 02115; and ;cDepartment of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 |
| |
| Abstract: | The Esx secretion pathway is conserved across Gram-positive bacteria. Esx-1, the best-characterized system, is required for virulence of Mycobacterium tuberculosis, although its precise function during infection remains unclear. Esx-3, a paralogous system present in all mycobacterial species, is required for growth in vitro. Here, we demonstrate that mycobacteria lacking Esx-3 are defective in acquiring iron. To compete for the limited iron available in the host and the environment, these organisms use mycobactin, high-affinity iron-binding molecules. In the absence of Esx-3, mycobacteria synthesize mycobactin but are unable to use the bound iron and are impaired severely for growth during macrophage infection. Mycobacteria thus require a specialized secretion system for acquiring iron from siderophores. |
| |
| Keywords: | secretion siderophore |
|
|
