Single Fibril Growth Kinetics of α-Synuclein

Wördehoff, Michael M.; Bannach, Oliver; Shaykhalishahi, Hamed; Kulawik, Andreas; Schiefer, Stephanie; Willbold, Dieter; Hoyer, Wolfgang; Birkmann, Eva

doi:10.1016/j.jmb.2015.01.020

Cited by 54 publications

(71 citation statements)

References 44 publications

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“…Wt asyn fibril seeds were imaged by TIRFM as particles with several fibrillation sites,r esulting in af ibril network after quiescent incubation with wt a-syn monomers (Figure 2d). [15] In contrast, fibril networks were not formed when a-synCC was incubated with wt a-syn fibril seeds,i na greement with the finding that a-synCC is non-fibrillogenic (Figure 2d). Incubation of wt a-syn monomers with wt a-syn fibril seeds did not lead to the formation of fibril networks when a-synCC was present (Figure 2d).…”

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confidence: 76%

Contact between the β1 and β2 Segments of α‐Synuclein that Inhibits Amyloid Formation

et al. 2015

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Conversion of the intrinsically disordered protein α-synuclein (α-syn) into amyloid aggregates is a key process in Parkinson's disease. The sequence region 35-59 contains β-strand segments β1 and β2 of α-syn amyloid fibril models and most disease-related mutations. β1 and β2 frequently engage in transient interactions in monomeric α-syn. The consequences of β1-β2 contacts are evaluated by disulfide engineering, biophysical techniques, and cell viability assays. The double-cysteine mutant α-synCC, with a disulfide linking β1 and β2, is aggregation-incompetent and inhibits aggregation and toxicity of wild-type α-syn. We show that α-syn delays the aggregation of amyloid-β peptide and islet amyloid polypeptide involved in Alzheimer's disease and type 2 diabetes, an effect enhanced in the α-synCC mutant. Tertiary interactions in the β1-β2 region of α-syn interfere with the nucleation of amyloid formation, suggesting promotion of such interactions as a potential therapeutic approach.

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confidence: 76%

Contact between the β1 and β2 Segments of α‐Synuclein that Inhibits Amyloid Formation

et al. 2015

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“…For example, dynamic light scattering (DLS) 7 and fluorescence correlation spectroscopy 8 provide insights into the distributions of species based on the diffusional properties. Imaging techniques, such as atomic force microscopy, 9 total internal reflection fluorescence microscopy, 10 and superresolution fluorescence microscopy, 11 have been recently employed to directly probe the shape of aggregates, monitor fibril growth, and directly visualize the localization of aggregates within live cells.…”

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confidence: 99%

The First Step of Amyloidogenic Aggregation

et al. 2015

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The structural and dynamic characterization of the on-pathway intermediates involved in the mechanism of amyloid fibril formation is one of the major remaining biomedical challenges of our time. In addition to mature fibrils, various oligomeric structures are implicated in both the rate-limiting step of the nucleation process and the neuronal toxicity of amyloid deposition. Single-molecule fluorescence spectroscopy (SMFS) is an excellent tool for extracting most of the relevant information on these molecular systems, especially advanced multiparameter approaches, such as pulsed interleaved excitation (PIE). In our investigations of an amyloidogenic SH3 domain of α-spectrin, we have found dynamic oligomerization, even prior to incubation. Our single-molecule PIE experiments revealed that these species are small, mostly dimeric, and exhibit a loose and dynamic molecular organization. Furthermore, these experiments have allowed us to obtain quantitative information regarding the oligomer stability. These pre-amyloidogenic oligomers may potentially serve as the first target for fibrillization-prevention strategies.

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“…By means of single-molecule fluorescence resonance energy transfer (smFRET) experiments,asubpopulation of aggregates formed with fluorescently labelled a-synuclein has previously been shown to undergo as low structural rearrangement before growing into fibrils. [12] This conversion can generate more cross-b structure and the resulting aggregates were reported to be both, more resistant to proteinase-K and more toxic to cells.U nlabelled fibrils of amyloid-b or asynuclein can be imaged with total internal fluorescence (TIRF) microscopy and structurally specific dyes such as thioflavin T(ThT), [16,17] opening up the possibilities of studying aggregates in human biofluids. [18] At as ingle fibril level, dyes such as ThTo rC ongo Red have been shown to bind insulin fibrils in an ordered way,a nd by monitoring the intensity as af unction of the polarisation angle,t hese dye classes can be provide information on the structure of fibrils.…”

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Optical Structural Analysis of Individual α‐Synuclein Oligomers

et al. 2018

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Small aggregates of misfolded proteins play a key role in neurodegenerative disorders. Such species have proved difficult to study due to the lack of suitable methods capable of resolving these heterogeneous aggregates, which are smaller than the optical diffraction limit. We demonstrate here an all‐optical fluorescence microscopy method to characterise the structure of individual protein aggregates based on the fluorescence anisotropy of dyes such as thioflavin‐T, and show that this technology is capable of studying oligomers in human biofluids such as cerebrospinal fluid. We first investigated in vitro the structural changes in individual oligomers formed during the aggregation of recombinant α‐synuclein. By studying the diffraction‐limited aggregates we directly evaluated their structural conversion and correlated this with the potential of aggregates to disrupt lipid bilayers. We finally characterised the structural features of aggregates present in cerebrospinal fluid of Parkinson's disease patients and age‐matched healthy controls.

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Single Fibril Growth Kinetics of α-Synuclein

Cited by 54 publications

References 44 publications

Contact between the β1 and β2 Segments of α‐Synuclein that Inhibits Amyloid Formation

Contact between the β1 and β2 Segments of α‐Synuclein that Inhibits Amyloid Formation

The First Step of Amyloidogenic Aggregation

Optical Structural Analysis of Individual α‐Synuclein Oligomers

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