amyloidogenic proteins
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2022 ◽  
pp. 397-434
Author(s):  
Bani Kumar Pathak ◽  
Sandip Dey ◽  
Sukanya Mozumder ◽  
Jayati Sengupta

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 9
Author(s):  
Georgia I. Nasi ◽  
Foteini D. Aktypi ◽  
Panagiotis M. Spatharas ◽  
Nikolaos N. Louros ◽  
Paraskevi L. Tsiolaki ◽  
...  

Plant natriuretic peptides (PNPs) are hormones that have been extracted from many different species, with the Arabidopsis thaliana PNP (AtPNP-A) being the most studied among them. AtPNP-A is a signaling molecule that consists of 130 residues and is secreted into the apoplast, under conditions of biotic or abiotic stress. AtPNP-A has distant sequence homology with human ANP, a protein that forms amyloid fibrils in vivo. In this work, we investigated the amyloidogenic properties of a 34-residue-long peptide, located within the AtPNP-A sequence, in three different pH conditions, using transmission electron microscopy, X-ray fiber diffraction, ATR FT-IR spectroscopy, Congo red and Thioflavin T staining assays. We also utilize bioinformatics tools to study its association with known plant amyloidogenic proteins and other A. thaliana proteins. Our results reveal a new case of a pH-dependent amyloid forming peptide in A. thaliana, with a potential functional role.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7590
Author(s):  
Natalia Katina ◽  
Alisa Mikhaylina ◽  
Nelly Ilina ◽  
Irina Eliseeva ◽  
Vitalii Balobanov

The formation of amyloid fibrils is one of the variants of the self-organization of polypeptide chains. For the amyloid aggregation, the solution must be oversaturated with proteins. The interface of the liquid (solution) and solid (vessel walls) phases can trigger the adsorption of protein molecules, and the resulting oversaturation can initiate conformational transitions in them. In any laboratory experiment, we cannot exclude the presence of surfaces such as the walls of vessels, cuvettes, etc. However, in many works devoted to the study of amyloid formation, this feature is not considered. In our work, we investigated the behavior of the Aβ 1-40 peptide at the water–glass, water–quartz, and water–plastic interface. We carried out a series of simple experiments and showed that the Aβ 1-40 peptide is actively adsorbed on these surfaces, which leads to a significant interaction and aggregation of peptides. This means that the interface can be the place where the first amyloid nucleus appears. We suggest that this effect may also be one of the reasons for the difficulty of reproducing kinetic data when studying the aggregation of the amyloid of the Aβ 1-40 peptide and other amyloidogenic proteins


2021 ◽  
Author(s):  
Katharina Schellhaus ◽  
Maria Gierisch ◽  
Julia Vornberger ◽  
Jan Johansson ◽  
Nico Dantuma

Abstract Due to the inherent toxicity of protein aggregates, the propensity of natural, functional amyloidogenic proteins to aggregate must be tightly controlled to avoid negative consequences on cellular viability. The importance of controlled aggregation in biological processes is illustrated by spidroins, which are functional amyloidogenic proteins that form the basis for spider silk. Premature aggregation of spidroins is prevented by the N-terminal NT domain. Here we explored the potential of the engineered, spidroin-based NT* domain in preventing protein aggregation in the intracellular environment of human cells. We show that the NT* domain increases the soluble pool of a reporter protein carrying a ligand-regulatable aggregation domain. Interestingly, the NT* domain prevents the formation of aggregates independent of its position in the aggregation-prone protein. The ability of the NT* domain to inhibit ligand-regulated aggregation was evident both in the cytosolic and nuclear compartments, which are both highly relevant for human disorders linked to non-physiological protein aggregation. We conclude that the spidroin-derived NT* domain has a generic anti-aggregation activity, independent of position or subcellular location, that is also active in human cells and propose that the NT* domain can potentially be exploited in controlling protein aggregation of disease-associated proteins.


2021 ◽  
Author(s):  
Nikolaos N Louros ◽  
Meine Ramakers ◽  
Emiel Michiels ◽  
Katerina Konstantoulea ◽  
Chiara Morelli ◽  
...  

Heterotypic amyloid interactions between related protein sequences have been observed in functional and disease amyloids. While sequence homology seems to favour heterotypic amyloid interactions, we have no systematic understanding of the structural rules determining such interactions nor whether they inhibit or facilitate amyloid assembly. Using structure-based thermodynamic calculations and extensive experimental validation, we performed a comprehensive exploration of the defining role of sequence promiscuity in amyloid interactions. Using this knowledge, we demonstrate, using tau as a model system, that predicted cross-interactions driven by sequence homology indeed can modify nucleation, fibril morphology, kinetic assembly and cellular spreading of aggregates. We also find that these heterotypic amyloid interactions can result in the mis-localisation of brain-expressed protein sequences with prevalent activities in neurodegenerative disorders. Our findings suggest a structural mechanism by which the proteomic background can modulate the aggregation propensity of amyloidogenic proteins and discuss how such sequence-specific proteostatic perturbations could contribute to the selective cellular susceptibility of amyloid disease progression.


2021 ◽  
Author(s):  
Line Friis Bakmann Christensen ◽  
Saeid Hadi Alijanvand ◽  
Michał Burdukiewicz ◽  
Florian‐Alexander Herbst ◽  
Henrik Kjeldal ◽  
...  

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