The escherichia coli outer membrane β-barrel assembly machinery (Bam) crosstalks with the divisome

Elisa Consoli, Joen Luirink, Tanneke Den Blaauwen*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


The BAM is a macromolecular machine responsible for the folding and the insertion of integral proteins into the outer membrane of diderm Gram-negative bacteria. In Escherichia coli, it consists of a transmembrane β-barrel subunit, BamA, and four outer membrane lipoproteins (BamB-E). Using BAM-specific antibodies, in E. coli cells, the complex is shown to localize in the lateral wall in foci. The machinery was shown to be enriched at midcell with specific cell cycle timing. The inhibition of septation by aztreonam did not alter the BAM midcell localization substantially. Furthermore, the absence of late cell division proteins at midcell did not impact BAM timing or localization. These results imply that the BAM enrichment at the site of constriction does not require an active cell division machinery. Expression of the Tre1 toxin, which impairs the FtsZ filamentation and therefore midcell localization, resulted in the complete loss of BAM midcell enrichment. A similar effect was observed for YidC, which is involved in the membrane insertion of cell division proteins in the inner membrane. The presence of the Z-ring is needed for preseptal peptidoglycan (PG) synthesis. As BAM was shown to be embedded in the PG layer, it is possible that BAM is inserted preferentially simultaneously with de novo PG synthesis to facilitate the insertion of OMPs in the newly synthesized outer membrane.

Original languageEnglish
Article number12101
Pages (from-to)1-16
Number of pages16
JournalInternational Journal of Molecular Sciences
Issue number22
Publication statusPublished - 2 Nov 2021

Bibliographical note

Funding Information:
This research was funded by the European Union?s Horizon 2020 research and innovation program under the Marie Sk?odowska-Curie grant agreement No. 721484 via the International Training Network Train2Target.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • BAM complex
  • Divisome
  • Escherichia coli
  • Immunolabelling
  • Sec machinery
  • β-barrel assembly machinery


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