Multiple roles of LpxE in the biogenesis of the Gram-negative bacterial envelope. Shown is a schematic illustration of the multifunctional roles of LpxE in the biogenesis of the cell wall polymer (peptidoglycan), outer membrane (LPS), and inner membrane (PGP). Shared phosphatase activities of LpxEs from diverse bacteria, including Aquifex (Aquificales), Francisella (Gammaproteobacteria), Rhizobium (Alphaproteobacteria), and Helicobacter (Epsilonproteobacteria), toward lipid A and C55-PP are indicated by solid arrows, whereas the unique PGP phosphatase activity of LpxEAA is indicated by a dashed red line.