Journal Article

The two-component system WalKR provides an essential link between cell wall homeostasis and DNA replication in Staphylococcus aureus

McWilliam, Hamish E. G., Carter, Glen P., Howden, Benjamin P., Guerillot, Romain, Seemann, Torsten, Klatt, Stephan, Hachani, Abderrahman, McDevitt, Christopher A., Monk, Ian R., Sharkey, Liam K. R., Neville, Stephanie L., Stinear, Timothy P., Baines, Sarah L., Walsh, Calum J., Rossello, Fernando J., Cho, Ellie, Pidot, Sacha J., Lee, Jean Y. H., Turner, Adrianna M.

2023

Overview

Among the 16 two-component systems in the opportunistic human pathogen Staphylococcus aureus , only WalKR is essential. Like the orthologous systems in other Bacillota, S. aureus WalKR controls autolysins involved in peptidoglycan remodeling and is therefore intimately involved in cell division. However, despite the importance of WalKR in S. aureus , the basis for its essentiality is not understood and the regulon is poorly defined. Here, we defined a consensus WalR DNA-binding motif and the direct WalKR regulon by using functional genomics, including chromatin immunoprecipitation sequencing, with a panel of isogenic walKR mutants that had a spectrum of altered activities. Consistent with prior findings, the direct regulon includes multiple autolysin genes. However, this work also revealed that WalR directly regulates at least five essential genes involved in lipoteichoic acid synthesis ( ltaS ): translation ( rplK ), DNA compaction ( hup ), initiation of DNA replication ( dnaA , hup ) and purine nucleotide metabolism ( prs ). Thus, WalKR in S. aureus serves as a polyfunctional regulator that contributes to fundamental control over critical cell processes by coordinately linking cell wall homeostasis with purine biosynthesis, protein biosynthesis, and DNA replication. Our findings further address the essentiality of this locus and highlight the importance of WalKR as a bona fide target for novel anti-staphylococcal therapeutics. The opportunistic human pathogen Staphylococcus aureus uses an array of protein sensing systems called two-component systems (TCS) to sense environmental signals and adapt its physiology in response by regulating different genes. This sensory network is key to S. aureus versatility and success as a pathogen. Here, we reveal for the first time the full extent of the regulatory network of WalKR, the only staphylococcal TCS that is indispensable for survival under laboratory conditions. We found that WalKR is a master regulator of cell growth, coordinating the expression of genes from multiple, fundamental S. aureus cellular processes, including those involved in maintaining cell wall metabolism, protein biosynthesis, nucleotide metabolism, and the initiation of DNA replication.

• Publisher: American Society for Microbiology
• Subject: Antibiotics / Autolysins / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Bacteriology / Biosynthesis / Cell division / Cell growth / Cell Wall - genetics / Cell Wall - metabolism / Cell walls / ChIP-seq / Chromatin / Deoxyribonucleic acid / DNA / DNA biosynthesis / DNA Replication / Drug resistance / essential genes / Gene expression / Gene Expression Regulation, Bacterial / Gram-positive bacteria / Homeostasis / Immunoprecipitation / Kinases / Lipoteichoic acid / Mutation / Opportunist infection / Pathogens / Peptidoglycans / Protein arrays / Protein biosynthesis / Protein turnover / Proteins / regulation of gene expression / Replication initiation / Research Article / split luciferase / Staphylococcus aureus / Staphylococcus aureus - genetics / Staphylococcus aureus - growth & development / Staphylococcus aureus - metabolism / Staphylococcus aureus - physiology / Staphylococcus infections / two-component regulatory systems / Virulence