Signaling mechanism by the Staphylococcus aureus two-component system LytSR: role of acetyl phosphate in bypassing the cell membrane electrical potential sensor LytS

Abstract

The two-component system LytSR has been linked to the signal transduction of cell membrane electrical potential perturbation and is involved in the adaptation of Staphylococcus aureus to cationic antimicrobial peptides. It consists of a membrane-bound histidine kinase, LytS, which belongs to the family of multiple transmembrane-spanning domains receptors, and a response regulator, LytR, which belongs to the novel family of non-helix-turn-helix DNA-binding domain proteins. LytR regulates the expression of cidABC and lrgAB operons, the gene products of which are involved in programmed cell death and lysis. In vivo studies have demonstrated involvement of two overlapping regulatory networks in regulating the lrgAB operon, both depending on LytR. One regulatory network responds to glucose metabolism and the other responds to changes in the cell membrane potential. Herein, we show that LytS has autokinase activity and can catalyze a fast phosphotransfer reaction, with 50% of its phosphoryl group lost within 1 minute of incubation with LytR. LytS has also phosphatase activity. Notably, LytR undergoes phosphorylation by acetyl phosphate at a rate that is 2-fold faster than the phosphorylation by LytS. This observation is significant in lieu of the in vivo observations that regulation of the lrgAB operon is LytR-dependent in the presence of excess glucose in the medium. The latter condition does not lead to perturbation of the cell membrane potential but rather to the accumulation of acetate in the cell. Our study provides insights into the molecular basis for regulation of lrgAB in a LytR-dependent manner under conditions that do not involve sensing by LytS.

Comparative proteomic investigation of multiple methicillin-resistant Staphylococcus aureus strains generated through adaptive laboratory evolution

“…We observed that the transcript level of the pta gene and the abundance of the corresponding protein, phosphate acetyltransferase, was lower in S3D14 than in the ancestral ( Figures 6 C and 6E). Although there is no literature that explicitly associates this gene with DAP tolerance or resistance, it has been shown that acetyl phosphate is involved in the phosphorylation of LytR ( Patel and Golemi-Kotra, 2015 ), a member of the two-component system that regulates genes controlling cell apoptosis, autolysin activity, biofilm formation, and is also involved in the adaptation of S . aureus to CAMPs ( Patton et al., 2006 ; Sharma-Kuinkel et al., 2009 ).…”

Unusual Features of the Membrane Kinome ofTrypanosoma brucei

“…Another interesting observation is that many bacterial histidine kinases with several TMDs have been identified in genome-wide bioinformatic analyses [38]. These include the 5-TMD bearing Staphylococcus aureus LytS histidine kinase which acts as a sensor of membrane potential [39]. Another example is Bacillus subtilis DesK, in which TMDs are involved in signaling temperature-induced changes in membrane fluidity [40].…”

Resistance Mechanisms to Antimicrobial Peptides in Gram-Positive Bacteria

“…The agr global transcriptional regulator induced a super expression of dltD, a member of the dlt operon (Dunman et al, 2001). Another regulator is the LytSR, a transmembrane electrical potential sensor (Patel and Golemi-Kotra, 2015). AMP cell wall damage is partially due to changes in membrane polarization; therefore, deletion of LytSR increased susceptibility to HNP-1 and tPMPs, Interestingly, no conformational changes were found in mutant cells membrane, indicating an alternative resistance pathway (Yang et al, 2013).…”