Amyloids of multiple species: are they helpful in survival?

Abstract

Amyloids are primarily known for their roles in neurodegenerative disorders, as well as in systemic diseases like diabetes. Evolutionary forces tend to maintain a healthy set of heritable characteristics, while eliminating toxic or unfavourable elements; but amyloids seem to represent an exception to this fundamental concept. In addition to their presence in mammals, amyloids also persist in the proteome of many lower organisms that may be linked with possible roles in survival, which are still unexplored. Herein, we address some unanswered questions regarding amyloids: are these well-structured proteinaceous aggregates a by-product of inefficient folding events, or have they been retained in our protein repertoire for as yet unknown functional roles; and how do protein misfolding and associated disorders originate, despite the presence of protein quality-control systems inside the cells? This review aims to extend our current understanding about the multifaceted useful properties of amyloids and their functional interactions with other molecular pathways in various species; this may provide new insights to identify novel therapeutic strategies for ageing and neurodegenerative diseases.

Flavonoid-Based Nanomedicines in Alzheimer’s Disease Therapeutics: Promises Made, a Long Way To Go

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Complex Inclusion Bodies and Defective Proteome Hubs in Neurodegenerative Disease: New Clues, New Challenges

“…However, some lines of studies suggest that the unwanted accumulation of the different proteins into inclusion bodies is nothing more than an event of an age-bound decline in the activity and efficiency of cellular PQC systems, causing a plethora of systemic and nonsystemic pathologies, among which neurodegenerative diseases (NDDs) are the most common (Knowles and others 2014). Nevertheless, the occurrence of similar proteinaceous structures in prokaryotes, lower organisms, and different classes of higher animals further substantiates the notion that the formation of IBs is an evolutionarily conserved mechanism that may have meaningful structural and functional roles in the survival of organisms (Shively and others 2001; Upadhyay and Mishra 2018).…”

“…However, protein aggregation is not always pathological. Many organisms, including bacteria, invertebrates, and mammals, have proteins that can only perform their functions after polymerizing or forming amyloid aggregates (reviewed by Fowler and others 2007; Upadhyay and Mishra 2018).…”

The mechanisms of epigenetic inheritance: how diverse are they?

“…Amyloids are highly stable non-covalent protein aggregates that possess a set of specific structural features [for reviews see Baxa, 2008 andUpadhyay &Mishra, 2018]. Such aggregates are produced from abnormally folded protein molecules, and are able to self-perpetuate by the following mechanism (Prusiner, 1998;Wickner et al, 2000;Liebman & Chernoff, 2012).…”