Lipopolysaccharide transport and assembly at the outer membrane: the PEZ model

Nat Rev Microbiol. 2016 Jun;14(6):337-45. doi: 10.1038/nrmicro.2016.25. Epub 2016 Mar 30.


Gram-negative bacteria have a double-membrane cellular envelope that enables them to colonize harsh environments and prevents the entry of many clinically available antibiotics. A main component of most outer membranes is lipopolysaccharide (LPS), a glycolipid containing several fatty acyl chains and up to hundreds of sugars that is synthesized in the cytoplasm. In the past two decades, the proteins that are responsible for transporting LPS across the cellular envelope and assembling it at the cell surface in Escherichia coli have been identified, but it remains unclear how they function. In this Review, we discuss recent advances in this area and present a model that explains how energy from the cytoplasm is used to power LPS transport across the cellular envelope to the cell surface.

Publication types

  • Review

MeSH terms

  • Bacterial Outer Membrane Proteins / metabolism*
  • Biological Transport
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / metabolism
  • Lipopolysaccharides / chemistry
  • Lipopolysaccharides / metabolism*
  • Metabolic Networks and Pathways
  • Models, Biological*


  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • Lipopolysaccharides