Regulation of Ergothioneine Biosynthesis and Its Effect on Mycobacterium tuberculosis Growth and Infectivity

• Published in: The Journal of biological chemistry 2015-09, Vol.290 (38), p.23064-23076
• Main Authors: Richard-Greenblatt, Melissa, Bach, Horacio, Adamson, John, Peña-Diaz, Sandra, Li, Wu, Steyn, Adrie J.C., Av-Gay, Yossef
• Format: Article
• Language: English
• Subjects: Animals; bacterial protein kinase; bacterial signal transduction; Cell Line; ergothioneine; Ergothioneine - biosynthesis; Ergothioneine - genetics; histidine methylation; Mice; Microbiology; Models, Biological; Mycobacterium tuberculosis; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - metabolism; Mycobacterium tuberculosis - pathogenicity; Protein Kinases - genetics; Protein Kinases - metabolism; thiol; Tuberculosis - genetics; Tuberculosis - metabolism; Tuberculosis - pathology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M115.648642

Ergothioneine (EGT) is synthesized in mycobacteria, but limited knowledge exists regarding its synthesis, physiological role, and regulation. We have identified Rv3701c from Mycobacterium tuberculosis to encode for EgtD, a required histidine methyltransferase that catalyzes first biosynthesis step in EGT biosynthesis. EgtD was found to be phosphorylated by the serine/threonine protein kinase PknD. PknD phosphorylates EgtD both in vitro and in a cell-based system on Thr213. The phosphomimetic (T213E) but not the phosphoablative (T213A) mutant of EgtD failed to restore EGT synthesis in a ΔegtD mutant. The findings together with observed elevated levels of EGT in a pknD transposon mutant during in vitro growth suggests that EgtD phosphorylation by PknD negatively regulates EGT biosynthesis. We further showed that EGT is required in a nutrient-starved model of persistence and is needed for long term infection of murine macrophages. Background:Mycobacterium tuberculosis synthesizes ergothioneine, a sulfur-containing molecule with unknown function. Results:egtD encodes for a histidine methyltransferase that is essential for ergothioneine biosynthesis and is negatively regulated through M. tuberculosis serine/threonine protein kinase D. Conclusion:M. tuberculosis modulates intracellular ergothioneine levels in response to starvation. Significance: Mechanisms by which M. tuberculosis senses and adapts to nutrient starvation is essential for understanding persistence and disease latency.