Journal Article

The Escherichia coli Outer Membrane β-Barrel Assembly Machinery (BAM) Crosstalks with the Divisome

Consoli, Elisa, den Blaauwen, Tanneke, Luirink, Joen

2021

Overview

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.

• Publisher: MDPI AG,MDPI
• Subject: Antibiotics / Bacteria / Bacterial Outer Membrane Proteins - genetics / Bacterial Outer Membrane Proteins - ultrastructure / Bacterial Proteins - genetics / Bacterial Proteins - ultrastructure / Cell cycle / Cell division / Cell Division - genetics / Cytoskeletal Proteins - genetics / Cytoskeletal Proteins - ultrastructure / E coli / Escherichia coli - chemistry / Escherichia coli - genetics / Escherichia coli Infections - genetics / Escherichia coli Infections - microbiology / Escherichia coli Proteins - genetics / Escherichia coli Proteins - ultrastructure / Gram-negative bacteria / Gram-Negative Bacteria - genetics / Gram-Negative Bacteria - ultrastructure / Lipids / Lipoproteins - genetics / Lipoproteins - ultrastructure / Localization / Machinery / Membrane Transport Proteins - genetics / Membrane Transport Proteins - ultrastructure / Protein Folding / Protein Multimerization - genetics / Proteins