Depletion of phosphatidylethanolamine affects secretion of Escherichia coli alkaline phosphatase and its transcriptional expression

In this report we demonstrate that depletion of the major phospholipid phosphatidylethanolamine, a single non-bilayer forming phospholipid of Escherichia call, significantly reduces the secretion efficiency of alkaline phosphatase in vivo. Secretion, ho,vel cr, is correlated with the content in membranes of cardiolipin, which in combination with selected divalent cations has a strong tendency to adopt a non-bilayer state indicating the possible involvement of lipid polymorphism in efficient protein secretion, Depletion of this zwitterionic phospholipid also inhibits expression of the protein controlled by the endogenous P-PHO promoter but not the P-BAD promoter, which is suggested to be due to the effect of unbalanced phospholipid composition on the orthophosphate signal transduction system (Pho regulon) through an effect on its membrane hound sensor. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.