Manganese Transport and the Role of Manganese in Virulence

Two areas of research have recently converged to highlight important roles for Mn²⁺ in pathogenesis: the recognition that both bacterial Nramp homologs and members of LraI family of proteins are Mn²⁺ transporters. Their mutation is associated with decreased virulence of various bacterial species. Thus, Mn²⁺ appears to be essential for bacterial virulence. This review describes what is currently known about Mn²⁺ transport in prokaryotes and how prokaryotic Mn²⁺ transport is regulated. Some of the phenotypes that arise when microorganisms lack Mn²⁺ are then discussed, with an emphasis on those phenotypes involving pathogenesis. The concluding section describes possible enzymatic roles for Mn²⁺ that might help explain why Mn²⁺ is necessary for virulence.