Faculty Collaboration Database

Functional Dissection of the CroRS Two-Component System Required for Resistance to Cell Wall Stressors in Enterococcus faecalis. J Bacteriol 2016 Apr;198(8):1326-36

Date

02/18/2016

Pubmed ID

26883822

Pubmed Central ID

PMC4859583

DOI

10.1128/JB.00995-15

Scopus ID

2-s2.0-84963807323 (requires institutional sign-in at Scopus site)   29 Citations

Abstract

UNLABELLED: Bacteria use two-component signal transduction systems (TCSs) to sense and respond to environmental changes via a conserved phosphorelay between a sensor histidine kinase and its cognate response regulator. The opportunistic pathogen Enterococcus faecalis utilizes a TCS comprised of the histidine kinase CroS and the response regulator CroR to mediate resistance to cell wall stresses such as cephalosporin antibiotics, but the molecular details by which CroRS promotes cephalosporin resistance have not been elucidated. Here, we analyzed mutants of E. faecalis carrying substitutions in CroR and CroS to demonstrate that phosphorylated CroR drives resistance to cephalosporins, and that CroS exhibits kinase and phosphatase activities to control the level of CroR phosphorylation in vivo. Deletion of croS in various lineages of E. faecalis revealed a CroS-independent mechanism for CroR phosphorylation and led to the identification of a noncognate histidine kinase capable of influencing CroR (encoded by OG1RF_12162; here called cisS). Further analysis of this TCS network revealed that both systems respond to cell wall stress.

IMPORTANCE: TCSs allow bacteria to sense and respond to many different environmental conditions. The opportunistic pathogen Enterococcus faecalis utilizes the CroRS TCS to mediate resistance to cell wall stresses, including clinically relevant antibiotics such as cephalosporins and glycopeptides. In this study, we use genetic and biochemical means to investigate the relationship between CroRS signaling and cephalosporin resistance in E. faecalis cells. Through this, we uncovered a signaling network formed between the CroRS TCS and a previously uncharacterized TCS that also responds to cell wall stress. This study provides mechanistic insights into CroRS signaling and cephalosporin resistance in E. faecalis.

Author List

Kellogg SL, Kristich CJ

Author

Christopher J. Kristich PhD Professor in the Microbiology and Immunology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amino Acid Sequence
Anti-Bacterial Agents
Bacterial Proteins
Cell Wall
Cephalosporins
Drug Resistance, Bacterial
Enterococcus faecalis
Gene Expression Regulation, Bacterial
Microbial Sensitivity Tests
Molecular Sequence Data
Mutation
Phosphorylation
Signal Transduction