AgfC and AgfE facilitate extracellular thin aggregative fimbriae synthesis in Salmonella Enteritidis

Gibson, Deanna L.; White, Aaron P.; Rajotte, C. M.; Kay, William W.

doi:10.1099/mic.0.2006/000935-0

Cited by 64 publications

(74 citation statements)

References 55 publications

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“…However, in contrast to other amyloid fibrils, which can often be solubilized by treatment with denaturants such as guanidine hydrochloride or solvents such as dimethyl sulfoxide (9), treatment with acids such as formic and TFA has been reported to be the only method capable of depolymerizing hydrophobin rodlets and regenerating the monomeric form of the hydrophobin proteins in solution (10,11). This is similar to the curli and tafi fibrils produced by bacteria, which have been shown to be functional amyloid and which also require treatment with formic acid for dissolution and regeneration of the monomeric, soluble component proteins (12,13).…”

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confidence: 60%

Recruitment of Class I Hydrophobins to the Air:Water Interface Initiates a Multi-step Process of Functional Amyloid Formation

Morris

Ren

Macindoe

et al. 2011

Journal of Biological Chemistry

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Class I fungal hydrophobins form amphipathic monolayers composed of amyloid rodlets. This is a remarkable case of functional amyloid formation in that a hydrophobic:hydrophilic interface is required to trigger the self-assembly of the proteins. The mechanism of rodlet formation and the role of the interface in this process have not been well understood. Here, we have studied the effect of a range of additives, including ionic liquids, alcohols, and detergents, on rodlet formation by two class I hydrophobins, EAS and DewA. Although the conformation of the hydrophobins in these different solutions is not altered, we observe that the rate of rodlet formation is slowed as the surface tension of the solution is decreased, regardless of the nature of the additive. These results suggest that interface properties are of critical importance for the recruitment, alignment, and structural rearrangement of the amphipathic hydrophobin monomers. This work gives insight into the forces that drive macromolecular assembly of this unique family of proteins and allows us to propose a three-stage model for the interface-driven formation of rodlets.Class I hydrophobins are a family of small amphipathic proteins that are produced by filamentous fungi in a monomeric form but are able to self-assemble into amphipathic monolayers composed of amyloid-like structures known as rodlets (1-3). The polymerization of the hydrophobins occurs on contact with a hydrophobic:hydrophilic interface, such as an air:water boundary or when hydrophobins are secreted from the spores and come into contact with the air. Members of the hydrophobin family are characterized by the presence of four disulfide bonds. The amphipathic nature of hydrophobins drives them to the surface of solutions, where they reduce the surface tension (1).Some of the functional roles of the class I hydrophobins include acting as a surfactant at the air:water boundary to reduce the surface tension, which is a barrier to aerial growth of hyphae, and also to form a robust protein coat on spores. This coating provides a hydrophobic external surface that resists wetting and thus facilitates spore dispersal in air (4 -6). The class I hydrophobin rodlets share many of the structural characteristics of amyloid fibrils; formation of the insoluble, fibrillar rodlets is accompanied by conformational change to an ordered cross-␤-secondary structure form and the polymerized rodlets, but not the monomeric form of the protein, bind to the dye thioflavin T (ThT) 4 (2, 7, 8). However, in contrast to other amyloid fibrils, which can often be solubilized by treatment with denaturants such as guanidine hydrochloride or solvents such as dimethyl sulfoxide (9), treatment with acids such as formic and TFA has been reported to be the only method capable of depolymerizing hydrophobin rodlets and regenerating the monomeric form of the hydrophobin proteins in solution (10,11). This is similar to the curli and tafi fibrils produced by bacteria, which have been shown to be functional amyloid and which also req...

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mentioning

confidence: 60%

Recruitment of Class I Hydrophobins to the Air:Water Interface Initiates a Multi-step Process of Functional Amyloid Formation

Morris

Ren

Macindoe

et al. 2011

Journal of Biological Chemistry

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“…Functional amyloids have been found in a wide range of organisms, from bacteria to mammals, with functions as diverse as biofilm formation, development of aerial structures, scaffolding, regulation of melanin synthesis, epigenetic control of polyamines and information transfer (21). There is a limited but growing by guest on March 28, 2019 http://www.jbc.org/ Downloaded from number of examples, including the curli homolog in Salmonella (23), FapC in many Pseudomonas species (24), TasA in Bacillus subtilis (25), the phenol soluble modulins (PSMs) (26) and the biofilm associated surface protein (27) in Staphylococcus aureus and the adhesin protein P1 in Streptococcus mutans (28), which are found to be able to form amyloid fibrils and are implicated in biofilm formation (29).…”

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confidence: 99%

Staphylococcus epidermidis small basic protein (Sbp) forms amyloid fibrils, consistent with its function as a scaffolding protein in biofilms

Wang

Jiang

Gao

et al. 2018

Journal of Biological Chemistry

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Biofilms are communities of microbes embedded in a microbial extracellular matrix. Their formation is considered the main virulence mechanism enabling the opportunistic bacterial pathogen Staphylococcus epidermidis to cause devastating nosocomial, implant-associated infections. Biofilms often contain proteins, and an 18-kDa protein called small basic protein (Sbp) recently was discovered in the S. epidermidis biofilm matrix and may serve as a scaffolding protein in both polysaccharide intercellular adhesion (PIA)-dependent and accumulation-associated protein (Aap)-dependent biofilm formations. In Aap-mediated biofilm formation, Sbp co-localizes with the domain-B of Aap, implying that Sbp directly interacts with Aap's Domain-B. However, the structure of Sbp and its interaction with Aap, as well as the molecular mechanism underlying Sbp's roles in biofilm formation, are incompletely understood. In this work, we used small-angle X-ray scattering (SAXS), NMR, analytical size-exclusion chromatography, and isothermal titration calorimetry analyses to determine the Sbp structure and characterize its interaction with Aap's Domain-B. We found that Sbp is monomeric and partially folded in solution, and, unexpectedly, we observed no direct interactions between Sbp and Aap Domain-B. Instead, we noted that Sbp forms amyloid fibrils both in vitro and in vivo. Atomic force, transmission electron, and confocal fluorescence microscopy methods confirmed the formation of Sbp amyloid fibrils and revealed their morphology. Taken together, the Sbp amyloid fibril structures identified here may account for Sbp's role as a scaffolding protein in the S. epidermidis biofilm matrix. Sbp forms functional amyloid fibrils 2Previously regarded as an innocuous human commensal that normally colonized the human skin and mucous membrane, Staphylococcus epidermidis has emerged as an leading opportunistic pathogen causing nosocomial infection associated with the permanent or intermittent indwelling medical devices (1,2). In contrast with its more virulent cousin Staphylococcus aureus, which produces an abundance of toxins, adherence factors, and cytolysins, the main virulence mechanism through which Staphylococcus epidermidis evade the host immune response relates to its capability of adhering and forming biofilms on biotic and abiotic surfaces (3). Staphylococcal biofilms are adherent multilayered communities of multicellular organisms embedded in self-produced extracellular matrix that are functionally resistant to antibiotics and components of the immune system (4). Therefore, S. epidermidis-mediated infections are difficult to treat and affect millions of patients worldwide annually, causing significant morbidity and mortality and a high burden for public health system (5).Biofilm formation is a complex, multifactorial process and can be divided into at least three stages: initial attachment to abiotic surfaces, protein-coated materials and host cells, and subsequent cell proliferation and accumulation via cell-cell adhesion leading to ...

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“…This second function of SipW is independent of its function in TasA and TapA maturation and involves a distinct signal peptidase domain (84). Functional amyloids are surprisingly common structural ECM components in a variety of bacterial biofilms, including S. aureus, Pseudomonas species, Salmonella enterica serovar enteritidis, and E. coli (85)(86)(87)(88)(89).…”

Section: Ecm Components In Bacterial Biofilmsmentioning

confidence: 99%

The Matrix Reloaded: How Sensing the Extracellular Matrix Synchronizes Bacterial Communities

Steinberg

Kolodkin‐Gal

2015

J Bacteriol

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In response to chemical communication, bacterial cells often organize themselves into complex multicellular communities that carry out specialized tasks. These communities are frequently referred to as biofilms, which involve the collective behavior of different cell types. Like cells of multicellular eukaryotes, the biofilm cells are surrounded by self-produced polymers that constitute the extracellular matrix (ECM), which binds them to each other and to the surface. In multicellular eukaryotes, it has been evident for decades that cell-ECM interactions control multiple cellular processes during development. While cells both in biofilms and in multicellular eukaryotes are surrounded by ECM and activate various genetic programs, until recently it has been unclear whether cell-ECM interactions are recruited in bacterial communicative behaviors. In this review, we describe the examples reported thus far for ECM involvement in control of cell behavior throughout the different stages of biofilm formation. The studies presented in this review have provided a newly emerging perspective of the bacterial ECM as an active player in regulation of biofilm development.

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AgfC and AgfE facilitate extracellular thin aggregative fimbriae synthesis in Salmonella Enteritidis

Cited by 64 publications

References 55 publications

Recruitment of Class I Hydrophobins to the Air:Water Interface Initiates a Multi-step Process of Functional Amyloid Formation

Recruitment of Class I Hydrophobins to the Air:Water Interface Initiates a Multi-step Process of Functional Amyloid Formation

Staphylococcus epidermidis small basic protein (Sbp) forms amyloid fibrils, consistent with its function as a scaffolding protein in biofilms

The Matrix Reloaded: How Sensing the Extracellular Matrix Synchronizes Bacterial Communities

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