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Insights into the structure and assembly of a bacterial cellulose secretion system.

ABSTRACT: Secreted exopolysaccharides present important determinants for bacterial biofilm formation, survival, and virulence. Cellulose secretion typically requires the concerted action of a c-di-GMP-responsive inner membrane synthase (BcsA), an accessory membrane-anchored protein (BcsB), and several additional Bcs components. Although the BcsAB catalytic duo has been studied in great detail, its interplay with co-expressed subunits remains enigmatic. Here we show that E. coli Bcs proteins partake in a complex protein interaction network. Electron microscopy reveals a stable, megadalton-sized macromolecular assembly, which encompasses most of the inner membrane and cytosolic Bcs components and features a previously unobserved asymmetric architecture. Heterologous reconstitution and mutational analyses point toward a structure-function model, where accessory proteins regulate secretion by affecting both the assembly and stability of the system. Altogether, these results lay the foundation for more comprehensive models of synthase-dependent exopolysaccharide secretion in biofilms and add a sophisticated secretory nanomachine to the diverse bacterial arsenal for virulence and adaptation.

SUBMITTER: Krasteva PV

PROVIDER: S-EPMC5727187 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Insights into the structure and assembly of a bacterial cellulose secretion system.

Krasteva Petya Violinova PV Bernal-Bayard Joaquin J Travier Laetitia L Martin Fernando Ariel FA Kaminski Pierre-Alexandre PA Karimova Gouzel G Fronzes Rémi R Ghigo Jean-Marc JM

Nature communications 20171212 1

Secreted exopolysaccharides present important determinants for bacterial biofilm formation, survival, and virulence. Cellulose secretion typically requires the concerted action of a c-di-GMP-responsive inner membrane synthase (BcsA), an accessory membrane-anchored protein (BcsB), and several additional Bcs components. Although the BcsAB catalytic duo has been studied in great detail, its interplay with co-expressed subunits remains enigmatic. Here we show that E. coli Bcs proteins partake in a c ...[more]

PMID: 29234007

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Insights into the structure and assembly of a bacterial cellulose secretion system.

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Insights into the structure and assembly of a bacterial cellulose secretion system.

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