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Toxic but tasty – temporal dynamics and network architecture of heme‐responsive two‐component signaling in Corynebacterium glutamicum
Author(s) -
Keppel Marc,
Piepenbreier Hannah,
Gätgens Cornelia,
Fritz Georg,
Frunzke Julia
Publication year - 2019
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14226
Subject(s) - corynebacterium glutamicum , heme , biology , response regulator , regulator , histidine kinase , biochemistry , detoxification (alternative medicine) , signalling , microbiology and biotechnology , computational biology , gene , enzyme , bacterial protein , medicine , alternative medicine , pathology , mutant
Summary Heme is an essential cofactor and alternative iron source for almost all bacterial species but may cause severe toxicity upon elevated levels and consequently, regulatory mechanisms coordinating heme homeostasis represent an important fitness trait. A remarkable scenario is found in several corynebacterial species, e.g. Corynebacterium glutamicum and Corynebacterium diphtheriae , which dedicate two paralogous, heme‐responsive two‐component systems, HrrSA and ChrSA, to cope with the Janus nature of heme. Here, we combined experimental reporter profiling with a quantitative mathematical model to understand how this particular regulatory network architecture shapes the dynamic response to heme. Our data revealed an instantaneous activation of the detoxification response ( hrtBA ) upon stimulus perception and we found that kinase activity of both kinases contribute to this fast onset. Furthermore, instant deactivation of the P hrtBA promoter is achieved by a strong ChrS phosphatase activity upon stimulus decline. While the activation of detoxification response is uncoupled from further factors, heme utilization is additionally governed by the global iron regulator DtxR integrating information on iron availability into the regulatory network. Altogether, our data provide comprehensive insights how TCS cross‐regulation and network hierarchy shape the temporal dynamics of detoxification ( hrtBA ) and utilization ( hmuO ) as part of a global homeostatic response to heme.