This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sperandeo, P.
Right arrow Articles by Polissi, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Sperandeo, P.
Right arrow Articles by Polissi, A.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2008, p. 4460-4469, Vol. 190, No. 13
0021-9193/08/$08.00+0     doi:10.1128/JB.00270-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Functional Analysis of the Protein Machinery Required for Transport of Lipopolysaccharide to the Outer Membrane of Escherichia coli{triangledown} ,{dagger}

Paola Sperandeo,1 Fion K. Lau,2 Andrea Carpentieri,3 Cristina De Castro,3 Antonio Molinaro,3 Gianni Dehò,4 Thomas J. Silhavy,2 and Alessandra Polissi1*

Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy,1 Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544,2 Dipartimento di Chimica Organica e Biochimica, Università di Napoli Federico II, Naples, Italy,3 Dipartimento di Scienze biomolecolari e Biotecnologie, Università degli Studi di Milano, Milan, Italy4

Received 22 February 2008/ Accepted 8 April 2008

Lipopolysaccharide (LPS) is an essential component of the outer membrane (OM) in most gram-negative bacteria, and its structure and biosynthetic pathway are well known. Nevertheless, the mechanisms of transport and assembly of this molecule at the cell surface are poorly understood. The inner membrane (IM) transport protein MsbA is responsible for flipping LPS across the IM. Additional components of the LPS transport machinery downstream of MsbA have been identified, including the OM protein complex LptD/LptE (formerly Imp/RlpB), the periplasmic LptA protein, the IM-associated cytoplasmic ATP binding cassette protein LptB, and LptC (formerly YrbK), an essential IM component of the LPS transport machinery characterized in this work. Here we show that depletion of any of the proteins mentioned above leads to common phenotypes, including (i) the presence of abnormal membrane structures in the periplasm, (ii) accumulation of de novo-synthesized LPS in two membrane fractions with lower density than the OM, and (iii) accumulation of a modified LPS, which is ligated to repeating units of colanic acid in the outer leaflet of the IM. Our results suggest that LptA, LptB, LptC, LptD, and LptE operate in the LPS assembly pathway and, together with other as-yet-unidentified components, could be part of a complex devoted to the transport of LPS from the periplasmic surface of the IM to the OM. Moreover, the location of at least one of these five proteins in every cellular compartment suggests a model for how the LPS assembly pathway is organized and ordered in space.

* Corresponding author. Mailing address: Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy. Phone: 39-02-64483431. Fax: 39-02-6448-3450. E-mail: alessandra.polissi{at}unimib.it

{triangledown} Published ahead of print on 18 April 2008.

{dagger} Supplemental material for this article may be found at http://jb.asm.org/.

Journal of Bacteriology, July 2008, p. 4460-4469, Vol. 190, No. 13
0021-9193/08/$08.00+0     doi:10.1128/JB.00270-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Kos, V., Cuthbertson, L., Whitfield, C. (2009). The Klebsiella pneumoniae O2a Antigen Defines a Second Mechanism for O Antigen ATP-binding Cassette Transporters. J. Biol. Chem. 284: 2947-2956 [Abstract] [Full Text]  
  • Ruiz, N. (2008). Bioinformatics identification of MurJ (MviN) as the peptidoglycan lipid II flippase in Escherichia coli. Proc. Natl. Acad. Sci. USA 105: 15553-15557 [Abstract] [Full Text]  
  • Ma, B., Reynolds, C. M., Raetz, C. R. H. (2008). Periplasmic orientation of nascent lipid A in the inner membrane of an Escherichia coli LptA mutant. Proc. Natl. Acad. Sci. USA 105: 13823-13828 [Abstract] [Full Text]  


Copyright © 2010 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»