To sense and adapt to their environment – and to successfully infect vertebrate hosts – bacteria employ two-component signaling systems (TCSs). Although the core TCS components (a signal sensor and a regulator of gene expression) are conserved across the bacterial kingdom, interactions between distinct TCSs are rare.
Eric Skaar, Ph.D., and colleagues have used chemical biology tools to probe TCS signaling in Bacillus anthracis, the cause of anthrax disease. They identified a new B. anthracis TCS (called HitRS), which is activated by several compounds that alter the integrity of the bacterial cell envelope. They found that HitRS interacts with HssRS – the B. anthracis TCS that senses heme and protects against heme toxicity – to coordinate a simultaneous response to both heme and cell envelope stress.
The findings, reported March 27 in PLOS Pathogens, demonstrate an unusual cross-regulation between two distinct TCSs and suggest that a coordinated response to heme and cell envelope stress is important for B. anthracis to infect the vertebrate host.
This research was supported by the Searle Scholars Program and by grants from the National Institutes of Health (AI057157, AI069233, AI073843).
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