scholarly journals Trends of Protein Aggregation in Neurodegenerative Diseases

Author(s):  
Abdulbaki Agbas
2021 ◽  
Author(s):  
Kazuki Murakami ◽  
Shinji Kajimoto ◽  
Daiki Shibata ◽  
Kunisato Kuroi ◽  
Fumihiko Fujii ◽  
...  

Liquid–liquid phase separation (LLPS) plays an important role in a variety of biological processes and is also associated with protein aggregation in neurodegenerative diseases. Quantification of LLPS is necessary to...


Author(s):  
Benjamin C Creekmore ◽  
Yi-Wei Chang ◽  
Edward B Lee

Abstract Neurodegenerative diseases are characterized by the accumulation of misfolded proteins. This protein aggregation suggests that abnormal proteostasis contributes to aging-related neurodegeneration. A better fundamental understanding of proteins that regulate proteostasis may provide insight into the pathophysiology of neurodegenerative disease and may perhaps reveal novel therapeutic opportunities. The 26S proteasome is the key effector of the ubiquitin-proteasome system responsible for degrading polyubiquitinated proteins. However, additional factors, such as valosin-containing protein (VCP/p97/Cdc48) and C9orf72, play a role in regulation and trafficking of substrates through the normal proteostasis systems of a cell. Nonhuman AAA+ ATPases, such as the disaggregase Hsp104, also provide insights into the biochemical processes that regulate protein aggregation. X-ray crystallography and cryo-electron microscopy (cryo-EM) structures not bound to substrate have provided meaningful information about the 26S proteasome, VCP, and Hsp104. However, recent cryo-EM structures bound to substrate have provided new information about the function and mechanism of these proteostasis factors. Cryo-EM and cryo-electron tomography data combined with biochemical data have also increased the understanding of C9orf72 and its role in maintaining proteostasis. These structural insights provide a foundation for understanding proteostasis mechanisms with near-atomic resolution upon which insights can be gleaned regarding the pathophysiology of neurodegenerative diseases.


2015 ◽  
Vol 36 (2) ◽  
pp. 72-77 ◽  
Author(s):  
Prajwal Ciryam ◽  
Rishika Kundra ◽  
Richard I. Morimoto ◽  
Christopher M. Dobson ◽  
Michele Vendruscolo

2014 ◽  
Vol 11 (6) ◽  
pp. 1503-1512 ◽  
Author(s):  
Fatemeh Shojaei ◽  
Naemeh Tavakolinia ◽  
Adeleh Divsalar ◽  
Thomas Haertlé ◽  
Ali Akbar Saboury ◽  
...  

Author(s):  
Juan R. Peinado ◽  
Kriti Chaplot ◽  
Timothy S. Jarvela ◽  
Edward Barbieri ◽  
James Shorter ◽  
...  

SUMMARYChaperone proteins perform vital functions in the maintenance of cellular proteostasis and play important roles during the development of neurodegenerative diseases involving protein aggregation. We have previously reported that a secreted neuronal chaperone known as proSAAS exhibits potent chaperone activity in vitro against protein aggregation and blocks the cytotoxic effects of amyloid and α-synuclein oligomers. Here we report that overexpression of proSAAS generates dense, membraneless 2 μm spheres which can increase by fusion up to 4 μM during expression within the cytoplasm. The presence of dense proSAAS spheres was confirmed using electron microscopy. ProSAAS spheres selectively sequestered GFP-TDP-43216-414 within their cores, resulting in cellular redistribution and retardation of degradation. ProSAAS expression was protective against TDP-43 cytotoxicity in a yeast model system. Aggregate sequestration via proSAAS encapsulation may provide protection from cell-to-cell transmission of aggregates and explain the as-yet unclear mechanism underlying the cytoprotective chaperone action of proSAAS.


2021 ◽  
Vol 14 ◽  
Author(s):  
Raja Elizabeth Estes ◽  
Bernice Lin ◽  
Arnav Khera ◽  
Marie Ynez Davis

Many neurodegenerative diseases are characterized by abnormal protein aggregates, including the two most common neurodegenerative diseases Alzheimer’s disease (AD) and Parkinson’s disease (PD). In the global search to prevent and treat diseases, most research has been focused on the early stages of the diseases, including how these pathogenic protein aggregates are initially formed. We argue, however, that an equally important aspect of disease etiology is the characteristic spread of protein aggregates throughout the nervous system, a key process in disease progression. Growing evidence suggests that both alterations in lipid metabolism and dysregulation of extracellular vesicles (EVs) accelerate the spread of protein aggregation and progression of neurodegeneration, both in neurons and potentially in surrounding glia. We will review how these two pathways are intertwined and accelerate the progression of AD and PD. Understanding how lipid metabolism, EV biogenesis, and EV uptake regulate the spread of pathogenic protein aggregation could reveal novel therapeutic targets to slow or halt neurodegenerative disease progression.


2019 ◽  
Author(s):  
John J. Chen ◽  
Diane L. Nathaniel ◽  
Preethi Raghavan ◽  
Maxine Nelson ◽  
Ruilin Tian ◽  
...  

ABSTRACTIntercellular propagation of protein aggregation is emerging as a key mechanism in the progression of several neurodegenerative diseases, including Alzheimer’s Disease and frontotemporal dementia. However, we lack a systematic understanding of the cellular path-ways controlling prion-like propagation. To uncover such pathways, we performed CRISPR interference (CRISPRi) screens in a human cell-based model of propagation of tau aggregation. Our screens uncovered that knockdown of several components of the ESCRT machinery, including CHMP6, or CHMP2A in combination with CHMP2B (a gene linked to familial fronto-temporal dementia), promote propagation of tau aggregation. We found that knockdown of these genes caused damage to endolysosomal membranes, consistent with a role for the ESCRT pathway in endolysosomal membrane repair. Leakiness of the endolysosomal compartment significantly enhanced prion-like propagation of tau aggregation, likely by making tau seeds more available to pools of cytoplasmic tau. Together, these findings suggest that endolysosomal escape is a critical step in tau propagation.


2021 ◽  
Vol 18 ◽  
Author(s):  
Ajoy Basak ◽  
Sarmistha Basak

: Self-attachment of proteins leading to the formation of highly insoluble protein oligomers and aggregates has become an important focus of research owing to its diverse implications in pathophysiology and diseases. This has become a more frequent phenomenon in most neurological and neurodegenerative diseases as well as in dementia. In recent years such event of protein aggregation has linked to other disease conditions, disorders or adverse health conditions. Interestingly, aggregation of protein also plays role in development, growth or metabolism. Most often physiological proteins are initially bio-synthesised in native or nascent geometrical forms or conformations but later they undergo specific folding pattern and thereby acquire a stable configuration that is biologically relevant and active. It is highly important that these proteins remain in their biologically active configuration in order to exert their functional properties. Any alteration or change to this structural configuration can be detrimental to their specific functions and may cause pathological consequences leading to the onset of diseases or disorders. Several factors such as the action of chaperones, binding partners, physiological metal ions, pH level, temperature, ionic strength, interfacial exposure (solid-liquid, liquid-liquid, gas-liquid), mutation and post translational modification, chemical changes, interaction with small molecules such as lipids, hormones, etc. and solvent environment have been either identified or proposed as important factors in conferring the ultimate status of protein structure and configuration. Among many misfolding protein conformations, self-assembly or aggregation is the most significant. It leads to the formation of highly oligomeric self-aggregates that precipitate and interfere with many biochemical processes with serious pathological consequences. The most common implication of protein aggregation leading to the formation of deposits / plaques of various morphological types is the onset of neurological and neurodegenerative diseases that include Alzheimer’s, Parkinson’s, Huntington, ALS (Amyotrophic Lateral Sclerosis), CJD (Creutzfeldt Jakob Dementia), Prion diseases, Amyloidosis and other forms of dementia. However increasingly studies revealed that protein aggregation may also be associated with other diseases such as cancer, type 2 diabetes, renal, corneal and cardiovascular diseases. Protein aggregation diseases are now considered as part of “Proteinopathy” which refers to conditions where proteins become structurally abnormal or fail to fold into stable normal configurations. In this review, we reflect on various aspects of protein self-aggregation, potential underlying causes, mechanism, role of secondary structures, pathological consequences and possible intervention strategies as reported in published literatures.


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