Open AccessDirected evolution reveals the mechanism of HitRS signaling transduction in Bacillus anthracis
Author(s) -
Huifeng Pi,
Michelle Chu,
Samuel J. Ivan,
Casey J. Latario,
Allen M. Toth,
Sophia M. Carlin,
Gideon H. Hillebrand,
Hannah K. Lin,
Jared D. Reppart,
Devin L. Stauff,
Eric P. Skaar
Publication year - 2020
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1009148
Subject(s) - signal transduction , biology , bacillus anthracis , hamp , computational biology , mechanism (biology) , genetics , transduction (biophysics) , signaling proteins , microbiology and biotechnology , biochemistry , bacteria , immunology , philosophy , epistemology , inflammation , hepcidin
Two c omponent s ystems (TCSs) are a primary mechanism of signal sensing and response in bacteria. Systematic characterization of an entire TCS could provide a mechanistic understanding of these important signal transduction systems. Here, genetic selections were employed to dissect the molecular basis of signal transduction by the HitRS system that detects cell envelope stress in the pathogen Bacillus anthracis . Numerous point mutations were isolated within HitRS, 17 of which were in a 50-residue HAMP domain. Mutational analysis revealed the importance of hydrophobic interactions within the HAMP domain and highlighted its essentiality in TCS signaling. In addition, these data defined residues critical for activities intrinsic to HitRS, uncovered specific interactions among individual domains and between the two signaling proteins, and revealed that phosphotransfer is the rate-limiting step for signal transduction. Furthermore, this study establishes the use of unbiased genetic selections to study TCS signaling and provides a comprehensive mechanistic understanding of an entire TCS.