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 phos phatidylethanolamine, a single non-bilayer forming phospholipid of Escheric hia call, significantly reduces the secretion efficiency of alkaline phosph atase in vivo. Secretion, ho,vel cr, is correlated with the content in memb ranes of cardiolipin, which in combination with selected divalent cations h as a strong tendency to adopt a non-bilayer state indicating the possible i nvolvement of lipid polymorphism in efficient protein secretion, Depletion of this zwitterionic phospholipid also inhibits expression of the protein c ontrolled by the endogenous P-PHO promoter but not the P-BAD promoter, whic h is suggested to be due to the effect of unbalanced phospholipid compositi on on the orthophosphate signal transduction system (Pho regulon) through a n effect on its membrane hound sensor. (C) 2001 Published by Elsevier Scien ce B.V. on behalf of the Federation of European Biochemical Societies.