Modulation of Curli Assembly and Pellicle Biofilm Formation by Chemical and Protein Chaperones

Andersson, Emma; Bengtsson, Camilla; Evans, Margery L.; Chorell, Erik; Sellstedt, Magnus; Lindgren, Åsa; Hufnagel, David A.; Bhattacharya, Moumita; Tessier, Peter M.; Wittung-Stafshede, Pernilla; Almqvist, Fredrik; Chapman, Matthew R.

doi:10.1016/j.chembiol.2013.07.017

Cited by 68 publications

(86 citation statements)

References 48 publications

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“…Images were captured on an Olympus SZX16 microscope with an Olympus DP72 camera. Pellicles were prepared by adding 2 l of the overnight culture into 2 ml of YESCA medium and grown statically at 26°C for 48 h (20). Pellicles were stained with 2 ml 0.1% (wt/vol) crystal violet for 5 min, followed by 3 washes with 2 ml H 2 O, and then were imaged on a Fluorchem 8900 (Alpha Innotech, San Leandro, CA).…”

Section: Methodsmentioning

confidence: 99%

The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli

et al. 2016

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The extracellular matrix protects Escherichia coli from immune cells, oxidative stress, predation, and other environmental stresses. Production of the E. coli extracellular matrix is regulated by transcription factors that are tuned to environmental conditions. The biofilm master regulator protein CsgD upregulates curli and cellulose, the two major polymers in the extracellular matrix of uropathogenic E. coli (UPEC) biofilms. We found that cyclic AMP (cAMP) regulates curli, cellulose, and UPEC biofilms through csgD. The alarmone cAMP is produced by adenylate cyclase (CyaA), and deletion of cyaA resulted in reduced extracellular matrix production and biofilm formation. The catabolite repressor protein (CRP) positively regulated csgD transcription, leading to curli and cellulose production in the UPEC isolate, UTI89. Glucose, a known inhibitor of CyaA activity, blocked extracellular matrix formation when added to the growth medium. The mutant strains ⌬cyaA and ⌬crp did not produce rugose biofilms, pellicles, curli, cellulose, or CsgD. Three putative CRP binding sites were identified within the csgD-csgB intergenic region, and purified CRP could gel shift the csgD-csgB intergenic region. Additionally, we found that CRP binded upstream of kpsMT, which encodes machinery for K1 capsule production. Together our work shows that cAMP and CRP influence E. coli biofilms through transcriptional regulation of csgD. IMPORTANCE The catabolite repressor protein (CRP)-cyclic AMP (cAMP) complex influences the transcription of ϳ7% of genes on the Escherichia coli is a multifaceted Gram-negative bacterium that is equipped for survival in disparate environments ranging from the gastrointestinal and urinary tracts to waterways and soil (1). Growth of E. coli can occur with either planktonic or biofilm lifestyles, the transition between which requires a highly organized shift in gene expression. The biofilm lifestyle is characterized by adherence, slow growth, resistance to environmental insults, and production of an extracellular matrix (ECM) (2). CsgD is the major biofilm regulator of E. coli and of many other bacteria of the Enterobacteriaceae family (3-5), and it promotes the production of two E. coli surface appendages, the amyloid fiber curli and the fibrous glycan chain cellulose (2). CsgD represses the transcription of motility-associated genes, while mediating self and surface attachment (6-8).E. coli is found in ϳ80% of urinary tract infections (UTI), more than any other causative agent, and has the ability to thrive in the bladder and urinary tract environments (9). During UTI, uropathogenic E. coli (UPEC) uses various means to evade and colonize the host. Curli and other factors function in establishing an initial bacterial titer (10). Once in the bladder, E. coli utilizes type 1 pili to invade bladder epithelial cells (11). E. coli bacteria then form a biofilm-like structure known as an intracellular bacterial community (IBC), and cells are coated by the ECM component K1 for protection from host cell recognition ...

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Section: Methodsmentioning

confidence: 99%

The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli

et al. 2016

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“…prevents the curli-dependent pellicle biofilm formation by E. coli at the air-liquid interface of a static culture (40). Recently, cryo-EM data have shown that CsgE binds to the periplasmic domain of CsgG with 9:9 (CsgE:CsgG subunit) stoichiometry and forms a capping adaptor that closes off the periplasmic face of the CsgG secretion channel (37).…”

Section: Significancementioning

confidence: 99%

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Krezel

Cusumano

Pinkner

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Curli, consisting primarily of major structural subunit CsgA, are functional amyloids produced on the surface of Escherichia coli, as well as many other enteric bacteria, and are involved in cell colonization and biofilm formation. CsgE is a periplasmic accessory protein that plays a crucial role in curli biogenesis. CsgE binds to both CsgA and the nonameric pore protein CsgG. The CsgG-CsgE complex is the curli secretion channel and is essential for the formation of the curli fibril in vivo. To better understand the role of CsgE in curli formation, we have determined the solution NMR structure of a double mutant of CsgE (W48A/F79A) that appears to be similar to the wild-type (WT) protein in overall structure and function but does not form mixed oligomers at NMR concentrations similar to the WT. The well-converged structure of this mutant has a core scaffold composed of a layer of two α-helices and a layer of three-stranded antiparallel β-sheet with flexible N and C termini. The structure of CsgE fits well into the cryoelectron microscopy density map of the CsgG-CsgE complex. We highlight a striking feature of the electrostatic potential surface in CsgE structure and present an assembly model of the CsgG-CsgE complex. We suggest a structural mechanism of the interaction between CsgE and CsgA. Understanding curli formation can provide the information necessary to develop treatments and therapeutic agents for biofilm-related infections and may benefit the prevention and treatment of amyloid diseases. CsgE could establish a paradigm for the regulation of amyloidogenesis because of its unique role in curli formation.biofilm formation | intrinsically disordered protein | aggregation | protein-protein interaction | CsgG

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“…Fredrik Almqvist (Umea University, Umea, Sweden) discussed nonbiocidal approaches targeting pilus fibers and curli amyloids involved in biofilm formation. Dr. Almqvist described how the discovery and improvement of anti-␤-amyloid lead compounds not only could inhibit bacterial biofilm formation but also may inform studies on human amyloid-related diseases (29). Cagla Tukel (Temple University, Philadelphia, PA) showed surprising results suggesting that amyloidcontaining biofilms trigger autoimmunity.…”

Section: New Insights Into Antimicrobial Tolerance and Novel Targets mentioning

confidence: 99%

Biofilms 2015: Multidisciplinary Approaches Shed Light into Microbial Life on Surfaces

et al. 2016

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The 7th ASM Conference on Biofilms was held in Chicago, Illinois, from 24 to 29 October 2015. The conference provided an international forum for biofilm researchers across academic and industry platforms, and from different scientific disciplines, to present and discuss new findings and ideas. The meeting covered a wide range of topics, spanning environmental sciences, applied biology, evolution, ecology, physiology, and molecular biology of the biofilm lifestyle. This report summarizes the presentations with regard to emerging biofilm-related themes.

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Modulation of Curli Assembly and Pellicle Biofilm Formation by Chemical and Protein Chaperones

Cited by 68 publications

References 48 publications

The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli

The Catabolite Repressor Protein-Cyclic AMP Complex Regulates csgD and Biofilm Formation in Uropathogenic Escherichia coli

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Biofilms 2015: Multidisciplinary Approaches Shed Light into Microbial Life on Surfaces

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