MntP is a family of bacterial proteins with a signal peptide and four transmembrane domains. It is a putative manganese efflux pump, since deletion of the gene leads to profound manganese sensitivity and elevated intracellular manganese levels in bacteria. Manganese is a highly important trace nutrient for organisms from bacteria to humans, and acts as an important element in the defence against oxidative stress and as an enzyme cofactor [1].

1: The Escherichia coli MntR miniregulon includes genes encoding a small protein and an efflux pump required for manganese homeostasis. Waters LS, Sandoval M, Storz G; J Bacteriol. 2011;193:5887-5897. PMID:21908668