Insights into the role of lipoteichoic acids and MprF function in Bacillus subtilis

Gram-positive bacterial cells are protected from the environment by a cell envelope which comprises of layers of peptidoglycan that maintain the cell shape and teichoic acids polymers whose biological function remains unclear. In Bacillus subtilis , loss of all Class A Penicillin-Binding Proteins (aPBPs) which function in peptidoglycan synthesis is conditionally lethal. Here we show that this lethality is associated with an alteration of the lipoteichoic acids (LTA) and the accumulation of the major autolysin LytE in the cell wall. Our analysis provides further evidence that the length and abundance of LTA acts to regulate the cellular level and activity of autolytic enzymes, specifically LytE. Importantly, we identify a novel function for the aminoacyl-phosphatidylglycerol synthase MprF in the modulation of LTA biosynthesis in B. subtilis and Staphylococcus aureus . This finding has implications for our understanding of antimicrobial resistance (particularly daptomycin) in clinically relevant bacteria and the involvement of MprF in the virulence of pathogens, such as methicillin resistant S. aureus .