Bacterial nitrogen-related phosphotransferase systems: new insights into diverse roles in virulence, physiology, and central metabolism

Nitrogen-related phosphotransferase (PTS^Ntr) systems are highly conserved and widely distributed in proteobacteria. These systems are thought to enable bacteria to sense and respond to changes in cellular carbon and nitrogen availability. The PTS^Ntr is analogous to the carbohydrate phosphotransferase systems that carry out phosphorylation and uptake of specific carbohydrates. Instead of targeting carbohydrates, the PTS^Ntr influences metabolic flux, virulence, biofilm development, stress adaptation, and other phenotypes in ways that vary among different species. Mechanistic insights into the regulatory roles of the PTS^Ntr have emerged from studies in diverse bacteria, including <i>Escherichia coli</i>, agriculturally relevant nitrogen-fixing symbionts, and biotechnology-relevant and opportunistic pathogens of the <i>Pseudomonas</i> genus. In this review, we summarize both seminal and more recent discoveries underpinning the current understanding of PTS^Ntr and identify unifying themes that connect these systems across disparate species.