Protein aggregation in bacteria: the thin boundary between functionality and toxicity

Bednarska, Natalia G.; Schymkowitz, Joost; Rousseau, Frédéric; Eldere, Johan Van

doi:10.1099/mic.0.069575-0

Cited by 84 publications

(86 citation statements)

References 97 publications

(89 reference statements)

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“…Interestingly, phage- and amikacin-treated cells displayed similar inclusion bodies, previously reported when E. coli is exposed to aminoglycosides [39, 40]. We did not find in the literature similar intracellular changes in cells submitted to phage predation.…”

Section: Discussionsupporting

confidence: 71%

The Lysis of Pathogenic Escherichia coli by Bacteriophages Releases Less Endotoxin Than by β-Lactams

Dufour

Delattre

Ricard

et al. 2017

Clinical Infectious Diseases

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Section: Discussionsupporting

confidence: 71%

The Lysis of Pathogenic Escherichia coli by Bacteriophages Releases Less Endotoxin Than by β-Lactams

Dufour

Delattre

Ricard

et al. 2017

Clinical Infectious Diseases

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“…S6C), suggesting that the decrease in nitrocefin hydrolysis activity in the ⌬rsaF a F b strain is likely caused by internal RsaA accumulation. This result is consistent with recent findings that internal protein accumulation and aggregation can trigger decreased membrane permeability, altered membrane composition, and lipid arrangement in E. coli (56)(57)(58). Hence, RsaF a and RsaF b likely did not play a major role in providing outer membrane integrity to protect against toxicity of antimicrobials.…”

Section: Fig 2 Spotting On Pye Plates Shows That After 2 Days Of Incusupporting

confidence: 81%

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

Overton

Park

Yung

et al. 2016

Appl Environ Microbiol

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Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior. Caulobacter crescentus is unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF a and RsaF b , which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology to Escherichia coli TolC, the outer membrane channel of multidrug efflux pumps. Here we provide evidence that, unlike TolC, RsaF a and RsaF b are not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF a and RsaF b are required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF a and RsaF b led to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF a and RsaF b led to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF a and RsaF b in cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels in C. crescentus. IMPORTANCEDecreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates that Caulobacter crescentus has two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closest C. crescentus homologs to TolC in E. coli, do not process TolC functionality in C. crescentus. T he aquatic, aerobic bacterium Caulobacter crescentus, which is able to survive in low-nutrient environments (1), has been studied extensively as a model organism for cell cycle regulation (2-4). More recent studies revealed that C. crescentus is able to tolerate high concentrations of uranium (5). To understand the U tolerance mechanism in C. crescentus, our lab previously performed a screen using transp...

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“…This observation is in agreement with the results by Ma and Wood [34], showing that the Δ cobB strain exhibits increased oxidative and heat stress resistance. It is believed that soluble misfolded proteins are more toxic for cells than final insoluble aggregates [35]. Therefore, we suppose that faster formation of IBs also enabled Δ cobB cells to withstand the stress induced by recombinant protein production.…”

Section: Discussionmentioning

confidence: 91%

The effect of protein acetylation on the formation and processing of inclusion bodies and endogenous protein aggregates in Escherichia coli cells

Kuczyńska-Wiśnik

Moruno-Algara

Stojowska-Swędrzyńska

et al. 2016

Microb Cell Fact

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BackgroundAcetylation of lysine residues is a reversible post-translational modification conserved from bacteria to humans. Several recent studies have revealed hundreds of lysine-acetylated proteins in various bacteria; however, the physiological role of these modifications remains largely unknown. Since lysine acetylation changes the size and charge of proteins and thereby may affect their conformation, we assumed that lysine acetylation can stimulate aggregation of proteins, especially for overproduced recombinant proteins that form inclusion bodies.ResultsTo verify this assumption, we used Escherichia coli strains that overproduce aggregation-prone VP1GFP protein. We found that in ΔackA-pta cells, which display diminished protein acetylation, inclusion bodies were formed with a delay and processed faster than in the wild-type cells. Moreover, in ΔackA-pta cells, inclusion bodies exhibited significantly increased specific GFP fluorescence. In CobB deacetylase-deficient cells, in which protein acetylation was enhanced, the formation of inclusion bodies was increased and their processing was significantly inhibited. Similar results were obtained with regard to endogenous protein aggregates formed during the late stationary phase in ΔackA-pta and ΔcobB cells.ConclusionsOur studies revealed that protein acetylation affected the aggregation of endogenous E. coli proteins and the yield, solubility, and biological activity of a model recombinant protein. In general, decreased lysine acetylation inhibited the formation of protein aggregates, whereas increased lysine acetylation stabilized protein aggregates. These findings should be considered during the designing of efficient strategies for the production of recombinant proteins in E. coli cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0590-8) contains supplementary material, which is available to authorized users.

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Protein aggregation in bacteria: the thin boundary between functionality and toxicity

Cited by 84 publications

References 97 publications

The Lysis of Pathogenic Escherichia coli by Bacteriophages Releases Less Endotoxin Than by β-Lactams

The Lysis of Pathogenic Escherichia coli by Bacteriophages Releases Less Endotoxin Than by β-Lactams

Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

The effect of protein acetylation on the formation and processing of inclusion bodies and endogenous protein aggregates in Escherichia coli cells

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