Molecular mechanism of Thioflavin-T binding to amyloid fibrils

Biancalana, Matthew; Koide, Shohei

doi:10.1016/j.bbapap.2010.04.001

Cited by 1,749 publications

(1,632 citation statements)

References 61 publications

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“…This may be due to the short length, amino acid composition or individual morphology of the peptide. Similar observations for other peptide fibrils have been made by several laboratories (24,25).…”

Section: Resultssupporting

confidence: 74%

Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS

Macindoe

Kwan

Ren

et al. 2012

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

121

111

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The hydrophobin EAS from the fungus Neurospora crassa forms functional amyloid fibrils called rodlets that facilitate spore formation and dispersal. Self-assembly of EAS into fibrillar rodlets occurs spontaneously at hydrophobic:hydrophilic interfaces and the rodlets further associate laterally to form amphipathic monolayers. We have used site-directed mutagenesis and peptide experiments to identify the region of EAS that drives intermolecular association and formation of the cross-β rodlet structure. Transplanting this region into a nonamyloidogenic hydrophobin enables it to form rodlets. We have also determined the structure and dynamics of an EAS variant with reduced rodlet-forming ability. Taken together, these data allow us to pinpoint the conformational changes that take place when hydrophobins self-assemble at an interface and to propose a model for the amphipathic EAS rodlet structure.A myloid fibrils were first identified in association with human diseases, but recent discoveries show that the amyloid ultrastructure also contributes to important functions in normal biology (1, 2). In bacteria, fungi, insects, fish, and mammals, amyloid structures perform a wide variety of roles (3). Functional amyloids in the form of fibrillar rodlets composed of class I hydrophobin proteins are found in filamentous fungi. These hydrophobins are small proteins that are secreted as monomers and self-assemble into rodlets that pack to form amphipathic monolayers at hydrophilic: hydrophobic boundaries, such as the surface of the growth medium (4). These proteins are extremely surface active and lower the surface tension of the aqueous growth medium, allowing hyphae to break through the surface and to produce aerial structures (5, 6). Many of these aerial structures subsequently become coated with amyloid rodlets, creating a hydrophobic layer that serves multiple purposes, including conferring water resistance to spores for easier dispersal in air (7), preventing wetting or collapse of gas transfer channels (8), enhancing adherence to waxy surfaces such as leaves during infection of rice plants by Magnaporthe grisea (9), and mediating evasion of the immune system as is observed in Aspergillus fumigatus infections (10).Hydrophobins are characterized by the presence of eight cysteine residues that form four disulphide bonds, but the hydrophobin family can be further divided into two classes based on the spacing of the conserved cysteine residues and the nature of the amphipathic monolayers that they form (11). Class I, but not class II, hydrophobins form amyloid-like rodlets that are extremely robust and require treatment with strong acid to induce depolymerization. The amphipathic monolayers formed by class II hydrophobins are not fibrillar and can be dissociated by treatment with detergent and alcohol solutions. The soluble, monomeric forms of hydrophobins share a unique β-barrel topology, and all have a relatively large exposed hydrophobic area on the protein monomer surface (4). The diversity in sequence and chain length ...

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Section: Resultssupporting

confidence: 74%

Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS

Macindoe

Kwan

Ren

et al. 2012

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

121

111

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“…Therefore, we conducted a titration study to determine the minimum concentration required to observe a toxic effect in AC16 cells. In vitro fibril formation reactions were followed by monitoring the fluorescence intensity of thioflavin T (ThT) dye, which is enhanced when ThT binds to amyloid fibrils (35). The ThT fluorescence emission decreased as a function of fibril concentration (Fig.…”

Section: Resultsmentioning

confidence: 99%

Cell Damage in Light Chain Amyloidosis

Argany¹,

Lin²,

Misra³

et al. 2016

Journal of Biological Chemistry

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Light chain (AL) amyloidosis is an incurable human disease characterized by the misfolding, aggregation, and systemic deposition of amyloid composed of immunoglobulin light chains (LC). This work describes our studies on potential mechanisms of AL cytotoxicity. We have studied the internalization of AL soluble proteins and amyloid fibrils into human AC16 cardiomyocytes by using real time live cell image analysis. Our results show how external amyloid aggregates rapidly surround the cells and act as a recruitment point for soluble protein, triggering the amyloid fibril elongation. Soluble protein and external aggregates are internalized into AC16 cells via macropinocytosis. AL amyloid fibrils are shown to be highly cytotoxic at low concentrations. Additionally, caspase assays revealed soluble protein induces apoptosis, demonstrating different cytotoxic mechanisms between soluble protein and amyloid aggregates. This study emphasizes the complex immunoglobulin light chain-cell interactions that result in fibril internalization, protein recruitment, and cytotoxicity that may occur in AL amyloidosis. Light chain (AL)2 amyloidosis is a protein misfolding disease characterized by extracellular deposition of immunoglobulin light chains (LC) as amyloid fibrils. LC proteins are comprised of two distinct domains: the variable (V L ) and constant (C L ) domains (also called LC full-length (FL) protein to differentiate with the V L domain). In patients with AL amyloidosis, the LC aggregate and deposit in vital organs, causing organ failure and death (1). The factors governing deposition in individual tissues are unknown. Patients with cardiac AL amyloidosis have the worst prognosis, with a median survival of less than a year (2, 3).The finding that the V L was the primary component of amyloid fibrils influenced previous biophysical studies (4,5). Recent proteomic studies have demonstrated that amyloid deposits are likely heterogeneous in nature and can be formed by FL, V L , C L , or mixtures of all types of LC fragments (6 -8). Thermodynamic studies proposed a stabilizing role for the 3C L domain in the stability and a modulating effect on fibril formation (9). Recently, our laboratory has demonstrated that the C L domain modulates the amyloid formation reaction but has no effect on the stability of the protein (10).Soluble monoclonal LC, isolated from patients with amyloidosis, can impair rat cardiomyocyte function (11) and induce apoptotic events in mouse cardiomyocytes (12, 13). Also, urinederived LC can be internalized into primary rat cardiac fibroblasts (14) and primary human renal mesangial cells (15) through a pinocytic pathway (16) or via receptor, clathrin-mediated mechanisms, respectively (15).Within the amyloid field, it is widely accepted that oligomeric species are potentially more toxic than mature fibrils (17-20). However, toxicity associated with amyloid fibrils may also be pathologically relevant. Engel et al. (21) described a mechanism in which growth of islet amyloid associated polypeptides fibrils is re...

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“…2A), the proSAAS domain preceding the second furin consensus cleavage site at residues 181-184 (14); this site is known to be quantitatively cleaved in vivo (15,16). The effect of proSAAS on α-synuclein fibrillation was determined by monitoring the fluorescence intensity of thioflavin T (ThT), a fluorescent dye that increases in emission by several orders of magnitude after binding to amyloid fibrils (34). Within a given experiment, the half-time for fibrillation of α-synuclein alone, with a negative control protein (carbonic anhydrase) or varying concentrations of proSAAS (0.1-3.0 μM) ranged between 57 and 67 h ( Fig.…”

Section: Resultsmentioning

confidence: 99%

The neural chaperone proSAAS blocks α-synuclein fibrillation and neurotoxicity

Jarvela

Lam

Helwig

et al. 2016

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

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Emerging evidence strongly suggests that chaperone proteins are cytoprotective in neurodegenerative proteinopathies involving protein aggregation; for example, in the accumulation of aggregated α-synuclein into the Lewy bodies present in Parkinson’s disease. Of the various chaperones known to be associated with neurodegenerative disease, the small secretory chaperone known as proSAAS (named after four residues in the amino terminal region) has many attractive properties. We show here that proSAAS, widely expressed in neurons throughout the brain, is associated with aggregated synuclein deposits in the substantia nigra of patients with Parkinson’s disease. Recombinant proSAAS potently inhibits the fibrillation of α-synuclein in an in vitro assay; residues 158–180, containing a largely conserved element, are critical to this bioactivity. ProSAAS also exhibits a neuroprotective function; proSAAS-encoding lentivirus blocks α-synuclein-induced cytotoxicity in primary cultures of nigral dopaminergic neurons, and recombinant proSAAS blocks α-synuclein–induced cytotoxicity in SH-SY5Y cells. Four independent proteomics studies have previously identified proSAAS as a potential cerebrospinal fluid biomarker in various neurodegenerative diseases. Coupled with prior work showing that proSAAS blocks β-amyloid aggregation into fibrils, this study supports the idea that neuronal proSAAS plays an important role in proteostatic processes. ProSAAS thus represents a possible therapeutic target in neurodegenerative disease.

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Molecular mechanism of Thioflavin-T binding to amyloid fibrils

Cited by 1,749 publications

References 61 publications

Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS

Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS

Cell Damage in Light Chain Amyloidosis

The neural chaperone proSAAS blocks α-synuclein fibrillation and neurotoxicity

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