Figure 5.

Examples of bacteriocin resistance mechanisms in Staphylococcus aureus. I. In the ApsRS system, the sensing of cationic antimicrobial peptides (AMPs) results in the autophosphorylation of ApsS, followed by the phosphorylation of ApsR. The phosphorylated ApsR can bind to the upstream regions of mprF and dltABCD, increasing the expression of these factors. MprF is associated with the addition of lysine to phosphatidylglycerol in the cell membrane, and DltABCD is associated with the addition of alanine to teichoic acids on the cell wall. Amino acid incorporation causes a shift to a weak negative charge on the cell surfaces and makes the cell less sensitive to cationic AMPs. II. In the BraRS (NsaRS)/BraDE system, sensing of nisin A by BraDE results in the autophosphorylation of BraS, followed by the phosphorylation of BraR. The phosphorylated BraR can bind to the upstream region of vraDE, giving rise to the increased expression of an ABC transporter VraDE which expels the AMPs from the cell.