Multiple resistance and pH antiporter (Mrp) (Mrp)

The Multiple resistance and pH (Mrp) antiporter is a large, multi-subunit membrane protein complex essential for bacterial ion homeostasis and pH regulation (Ito et al., 2017). Typically composed of seven subunits (MrpA through MrpG), it functions as a secondary active transporter that utilizes the proton motive force to extrude monovalent cations, such as sodium (Na+) or potassium (K+), from the cytoplasm in exchange for external protons (Morino et al., 2014). This system is particularly critical for the survival of alkaliphilic bacteria and various human pathogens, including Staphylococcus aureus and Bacillus anthracis, under conditions of high salinity or alkaline pH (Kashyap et al., 2022). By maintaining a relatively neutral internal pH and low cytoplasmic sodium levels, the Mrp complex supports bioenergetic processes and cellular viability. Recent research has highlighted Mrp as a potential therapeutic target, as its disruption significantly attenuates the virulence of S. aureus in infection models and renders bacteria hypersensitive to environmental stress (Kashyap et al., 2022). While no clinical drugs currently target Mrp, experimental inhibitors like amiloride derivatives have been used in research to probe its function, and it remains an attractive candidate for novel antimicrobial strategies due to its absence in humans.

Other names

Mrp complexMrp systemNa+/H+ antiporter MrpCation/proton antiporter-3 familyCPA3MrpA-G system

Inhibition of the Mrp-mediated Na+/H+ exchange, which disrupts intracellular pH homeostasis and leads to sodium-induced toxicity in bacteria.