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NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli.

Publication ,  Journal Article
Schwechheimer, C; Rodriguez, DL; Kuehn, MJ
Published in: Microbiologyopen
June 2015

Outer membrane vesicles (OMVs) are ubiquitously secreted from the outer membrane (OM) of Gram-negative bacteria. These heterogeneous structures are composed of OM filled with periplasmic content from the site of budding. By analyzing mutants that have vesicle production phenotypes, we can gain insight into the mechanism of OMV budding in wild-type cells, which has thus far remained elusive. In this study, we present data demonstrating that the hypervesiculation phenotype of the nlpI deletion mutant of Escherichia coli correlates with changes in peptidoglycan (PG) dynamics. Our data indicate that in stationary phase cultures the nlpI mutant exhibits increased PG synthesis that is dependent on spr, consistent with a model in which NlpI controls the activity of the PG endopeptidase Spr. In log phase, the nlpI mutation was suppressed by a dacB mutation, suggesting that NlpI regulates penicillin-binding protein 4 (PBP4) during exponential growth. The data support a model in which NlpI negatively regulates PBP4 activity during log phase, and Spr activity during stationary phase, and that in the absence of NlpI, the cell survives by increasing PG synthesis. Further, the nlpI mutant exhibited a significant decrease in covalent outer membrane (OM-PG) envelope stabilizing cross-links, consistent with its high level of OMV production. Based on these results, we propose that one mechanism wild-type Gram-negative bacteria can use to modulate vesiculation is by altering PG-OM cross-linking via localized modulation of PG degradation and synthesis.

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Published In

Microbiologyopen

DOI

EISSN

2045-8827

Publication Date

June 2015

Volume

4

Issue

3

Start / End Page

375 / 389

Location

England

Related Subject Headings

  • Signal Transduction
  • Phenotype
  • Peptidoglycan
  • Mutation
  • Lipoproteins
  • Gene Expression Regulation, Bacterial
  • Gene Deletion
  • Escherichia coli Proteins
  • Escherichia coli
  • Cysteine Endopeptidases
 

Citation

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Schwechheimer, C., Rodriguez, D. L., & Kuehn, M. J. (2015). NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli. Microbiologyopen, 4(3), 375–389. https://doi.org/10.1002/mbo3.244
Schwechheimer, Carmen, Daniel L. Rodriguez, and Meta J. Kuehn. “NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli.Microbiologyopen 4, no. 3 (June 2015): 375–89. https://doi.org/10.1002/mbo3.244.
Schwechheimer C, Rodriguez DL, Kuehn MJ. NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli. Microbiologyopen. 2015 Jun;4(3):375–89.
Schwechheimer, Carmen, et al. “NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli.Microbiologyopen, vol. 4, no. 3, June 2015, pp. 375–89. Pubmed, doi:10.1002/mbo3.244.
Schwechheimer C, Rodriguez DL, Kuehn MJ. NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli. Microbiologyopen. 2015 Jun;4(3):375–389.
Journal cover image

Published In

Microbiologyopen

DOI

EISSN

2045-8827

Publication Date

June 2015

Volume

4

Issue

3

Start / End Page

375 / 389

Location

England

Related Subject Headings

  • Signal Transduction
  • Phenotype
  • Peptidoglycan
  • Mutation
  • Lipoproteins
  • Gene Expression Regulation, Bacterial
  • Gene Deletion
  • Escherichia coli Proteins
  • Escherichia coli
  • Cysteine Endopeptidases