%0 Journal Article
%T Infectivity versus Seeding in Neurodegenerative Diseases Sharing a Prion-Like Mechanism
%A Natalia Fern¨¢ndez-Borges
%A Hasier Era£¿a
%A Saioa R. Elezgarai
%A Chafik Harrathi
%A Mayela Gayosso
%A Joaqu¨ªn Castilla
%J International Journal of Cell Biology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/583498
%X Prions are considered the best example to prove that the biological information can be transferred protein to protein through a conformational change. The term ¡°prion-like¡± is used to describe molecular mechanisms that share similarities with the mammalian prion protein self-perpetuating aggregation and spreading characteristics. Since prions are presumably composed only of protein and are infectious, the more similar the mechanisms that occur in the different neurodegenerative diseases, the more these processes will resemble an infection. In vitro and in vivo experiments carried out during the last decade in different neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's diseases (PD), and amyotrophic lateral sclerosis (ALS) have shown a convergence toward a unique mechanism of misfolded protein propagation. In spite of the term ¡°infection¡± that could be used to explain the mechanism governing the diversity of the pathological processes, other concepts as ¡°seeding¡± or ¡°de novo induction¡± are being used to describe the in vivo propagation and transmissibility of misfolded proteins. The current studies are demanding an extended definition of ¡°disease-causing agents¡± to include those already accepted as well as other misfolded proteins. In this new scenario, ¡°seeding¡± would be a type of mechanism by which an infectious agent can be transmitted but should not be used to define a whole ¡°infection¡± process. 1. Introduction It has been some time since the old axiom, ¡°one protein¡ªone structure,¡± became obsolete [1]. This is most obvious for prion scientists that try to understand how different protein structures can originate from the same primary sequence. The idea that proteins must acquire a specific and unique conformation has shifted due to biochemical and structural evidence from neurodegenerative diseases showing that different folding states of the same protein are essential in certain biological processes. This concept was nicely expressed by Batch and colleagues: ¡°The misfolding and aggregation of proteins is often an accident waiting to happen. Consequently, organisms have developed sophisticated chaperone and quality-control systems to limit abnormal protein interactions and the accumulation of toxic aggregates¡± [2]. The ability of proteins to reach different isoforms has crucial consequences in the cell and in the whole organism as demonstrated in prion diseases, neurodegenerative pathologies where the prion protein (PrP) misfolding process is the key event. We will review the behavior of different proteins implicated in
%U http://www.hindawi.com/journals/ijcb/2013/583498/