An ABC transport system that maintains lipid asymmetry in the Gram-negative outer membrane

Juliana C. Malinverni, Thomas J. Silhavy

Research output: Contribution to journalArticle

188 Scopus citations

Abstract

The outer membranes (OMs) of Gram-negative bacteria have an asymmetric lipid distribution with lipopolysaccharides at the outer leaflet and phospholipids (PLs) at the inner leaflet. This lipid arrangement is essential for the barrier function of the OM and for the viability of most Gram-negative bacteria. Cells with OM assembly defects or cells exposed to harsh chemical treatments accumulate PLs in the outer leaflet of the OM and this disrupts lipopolysaccharide organization and increases sensitivity to small toxic molecules. We have identified an ABC transport system in Escherichia coli with predicted import function that serves to prevent PL accumulation in the outer leaflet of the OM. This highly conserved pathway, which we have termed the Mla pathway for its role in preserving OM lipid asymmetry, is composed of at least 6 proteins and contains at least 1 component in each cellular compartment. We propose that the Mla pathway constitutes a bacterial intermembrane PL trafficking system.

Original languageEnglish (US)
Pages (from-to)8009-8014
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number19
DOIs
StatePublished - May 12 2009

All Science Journal Classification (ASJC) codes

  • General

Keywords

  • Mla pathway
  • Phospholipid
  • VacJ
  • YrbC
  • pldA

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