Partially Unfolded States of β2-Microglobulin and Amyloid Formation in Vitro†

Biochemistry ◽  
2000 ◽  
Vol 39 (30) ◽  
pp. 8735-8746 ◽  
Author(s):  
Victoria J. McParland ◽  
Neil M. Kad ◽  
Arnout P. Kalverda ◽  
Anthony Brown ◽  
Patricia Kirwin-Jones ◽  
...  
Keyword(s):  
Amyloid Formation ◽  
Β2 Microglobulin ◽  
Partially Unfolded ◽  
Partially Unfolded States

scholarly journals The V30M Amyloidogenic Mutation Decreases the Rate of Refolding Kinetics of the Tetrameric Protein Transthyretin

2012 ◽  
Vol 27 ◽  
pp. 343-348 ◽  
Author(s):  
Catarina S. H. Jesus ◽  
Daniela C. Vaz ◽  
Maria J. M. Saraiva ◽  
Rui M. M. Brito
Keyword(s):  
Tryptophan Fluorescence ◽  
Amyloid Formation ◽  
Monomeric Species ◽  
Intrinsic Tryptophan Fluorescence ◽  
Tetrameric Structure ◽  
Partially Unfolded ◽  
Kinetics Of ◽  
Refolding Kinetics

Transthyretin (TTR) is a homotetrameric protein implicated in several amyloid diseases. The mechanism by which TTR is converted into elongated fibrillar assemblies has been extensively investigated, and numerous studies showed that dissociation of the native tetrameric structure into partially unfolded monomeric species precedes amyloid formation. The small differences observed in the crystal structures of different TTR variants, as well as the thermodynamics and kinetics of tetramer dissociation, do not seem to completely justify the amyloidogenic potential of different TTR variants. With this in mind, we have studied the refolding kinetics of WT-TTR and its most common amyloidogenic variant V30M-TTR, monitoring changes in intrinsic tryptophan fluorescence at different urea and protein concentrations. Our results demonstrate that thein vitrorefolding mechanisms of WT- and V30M-TTR are similar, involving a dimeric intermediate. However, there are large differences in the refolding rate constants for the two variants, specially close to physiological conditions. Interestingly, tetramer formation occurs at a much slower rate in the amyloidogenic variant V30M-TTR than in WT-TTR, which in thein vivosetting may promote the accumulation of monomeric species in the extracellular environment, resulting in higher susceptibility for aggregation and amyloid formation instead of spontaneous refolding.

scholarly journals Mechanism of the small ATP-independent chaperone Spy is substrate specific

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rishav Mitra ◽  
Varun V. Gadkari ◽  
Ben A. Meinen ◽  
Carlo P. M. van Mierlo ◽  
Brandon T. Ruotolo ◽  
...  
Keyword(s):  
Relative Affinity ◽  
Complex Protein ◽  
Partially Unfolded ◽  
Substrate Proteins ◽  
Partially Unfolded States

AbstractATP-independent chaperones are usually considered to be holdases that rapidly bind to non-native states of substrate proteins and prevent their aggregation. These chaperones are thought to release their substrate proteins prior to their folding. Spy is an ATP-independent chaperone that acts as an aggregation inhibiting holdase but does so by allowing its substrate proteins to fold while they remain continuously chaperone bound, thus acting as a foldase as well. The attributes that allow such dual chaperoning behavior are unclear. Here, we used the topologically complex protein apoflavodoxin to show that the outcome of Spy’s action is substrate specific and depends on its relative affinity for different folding states. Tighter binding of Spy to partially unfolded states of apoflavodoxin limits the possibility of folding while bound, converting Spy to a holdase chaperone. Our results highlight the central role of the substrate in determining the mechanism of chaperone action.

scholarly journals Formation of Amyloid Fibrils In Vitro from Partially Unfolded Intermediates of Human γC-Crystallin

2010 ◽  
Vol 51 (2) ◽  
pp. 672 ◽  
Author(s):  
Yongting Wang ◽  
Sarah Petty ◽  
Amy Trojanowski ◽  
Kelly Knee ◽  
Daniel Goulet ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Partially Unfolded

scholarly journals Deletion of Serf2 shifts amyloid conformation in an Aβ amyloid mouse model

2021 ◽  
Author(s):  
E. Stroo ◽  
L. Janssen ◽  
O. Sin ◽  
W. Hogewerf ◽  
M. Koster ◽  
...  
Keyword(s):  
Mouse Model ◽  
Amyloid Fibrils ◽  
Mammalian Brain ◽  
Amyloid Formation ◽  
List Type ◽  
Lung Maturation ◽  
Disease Manifestation ◽  
Aβ Amyloid ◽  
Perinatal Lethality

AbstractNeurodegenerative diseases like Alzheimer, Parkinson and Huntington disease are characterized by aggregation-prone proteins that form amyloid fibrils through a nucleation process. Despite the shared β-sheet structure, recent research has shown that structurally different polymorphs exist within fibrils of the same protein. These polymorphs are associated with varying levels of toxicity and different disease phenotypes. MOAG-4 and its human orthologs SERF1 and SERF2 have previously been shown to modify the nucleation and drive amyloid formation and protein toxicity in vitro and in C. elegans. To further explore these findings, we generated a Serf2 knockout (KO) mouse model and crossed it with the APPPS1 mouse model for Aβ amyloid pathology. Full-body KO of Serf2 resulted in a developmental delay and perinatal lethality due to insufficient lung maturation. Therefore, we proceeded with a brain-specific Serf2 KO, which was found to be viable. We examined the Aβ pathology at 1 and 3 months of age, which is before and after the start of amyloid deposition. We show that SERF2 deficiency does not affect the production and overall Aβ levels. Serf2 KO-APPPS1 mice displayed an increased intracellular Aβ accumulation at 1 month and a higher number of Aβ deposits compared to APPPS1 mice with similar Aβ levels. Moreover, conformation-specific dyes and electron microscopy revealed a difference in the structure and amyloid content of these Aβ deposits. Together, our results reveal that SERF2 causes a structural shift in Aβ aggregation in a mammalian brain. These findings indicate that a single endogenous factor may contribute to amyloid polymorphisms, allowing for new insights into this phenomenon’s contribution to disease manifestation.HighlightsLoss of SERF2 slows embryonic development and causes perinatal lethalitySERF2 affects proliferation in a cell-autonomous fashionBrain-specific Serf2 knockout does not affect viability or Aβ productionBrain deletion of Serf2 shifts the amyloid conformation of Aβ

In-vitro and in-silico investigation of protective mechanisms of crocin against E46K α-synuclein amyloid formation

2019 ◽  
Vol 46 (4) ◽  
pp. 4279-4292 ◽  
Author(s):  
Marzieh Ghasemi Tigan ◽  
Arezou Ghahghaei ◽  
Milad Lagzian
Keyword(s):  
In Silico ◽  
Amyloid Formation ◽  
Protective Mechanisms

scholarly journals Differential effects of Cu2+ and Fe3+ ions on in vitro amyloid formation of biologically-relevant α-synuclein variants

BioMetals ◽  
2020 ◽  
Vol 33 (2-3) ◽  
pp. 97-106 ◽  
Author(s):  
Emma Lorentzon ◽  
Ranjeet Kumar ◽  
Istvan Horvath ◽  
Pernilla Wittung-Stafshede
Keyword(s):  
Amyloid Formation ◽  
Differential Effects ◽  
Biologically Relevant

scholarly journals Collagen I Weakly Interacts with the β-Sheets of β2-Microglobulin and Enhances Conformational Exchange To Induce Amyloid Formation

2019 ◽  
Vol 142 (3) ◽  
pp. 1321-1331
Author(s):  
Cody L. Hoop ◽  
Jie Zhu ◽  
Shibani Bhattacharya ◽  
Caitlyn A. Tobita ◽  
Sheena E. Radford ◽  
...  
Keyword(s):  
Conformational Exchange ◽  
Collagen I ◽  
Amyloid Formation ◽  
Β2 Microglobulin ◽  
Β Sheets

scholarly journals Desmin forms toxic, seeding-competent amyloid aggregates that persist in muscle fibers

2019 ◽  
Vol 116 (34) ◽  
pp. 16835-16840 ◽  
Author(s):  
Niraja Kedia ◽  
Khalid Arhzaouy ◽  
Sara K. Pittman ◽  
Yuanzi Sun ◽  
Mark Batchelor ◽  
...  
Keyword(s):  
Amyloid Fibrils ◽  
Therapeutic Potential ◽  
Epigallocatechin Gallate ◽  
Amyloid Formation ◽  
Myofibrillar Myopathy ◽  
Protein Aggregate ◽  
Disease Mutations ◽  
Amyloid Aggregates ◽  
Associated Proteins

Desmin-associated myofibrillar myopathy (MFM) has pathologic similarities to neurodegeneration-associated protein aggregate diseases. Desmin is an abundant muscle-specific intermediate filament, and disease mutations lead to its aggregation in cells, animals, and patients. We reasoned that similar to neurodegeneration-associated proteins, desmin itself may form amyloid. Desmin peptides corresponding to putative amyloidogenic regions formed seeding-competent amyloid fibrils. Amyloid formation was increased when disease-associated mutations were made within the peptide, and this conversion was inhibited by the anti-amyloid compound epigallocatechin-gallate. Moreover, a purified desmin fragment (aa 117 to 348) containing both amyloidogenic regions formed amyloid fibrils under physiologic conditions. Desmin fragment-derived amyloid coaggregated with full-length desmin and was able to template its conversion into fibrils in vitro. Desmin amyloids were cytotoxic to myotubes and disrupted their myofibril organization compared with desmin monomer or other nondesmin amyloids. Finally, desmin fragment amyloid persisted when introduced into mouse skeletal muscle. These data suggest that desmin forms seeding-competent amyloid that is toxic to myofibers. Moreover, small molecules known to interfere with amyloid formation and propagation may have therapeutic potential in MFM.

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