To aggregate or not to aggregate - Is it a matter of the ribosome?

Neurodegenerative syndromes present as proteinopathies - does ribosomal infidelity contribute to the protein toxicity that is the driving force for neuronal cell loss? Intracellular and extracellular protein aggregates overwhelm the clearance capacity of cells and tissues. Proteins aggregate when hydrophobic residues are exposed. Hydrophobic residues become exposed when proteins are misfolded. Protein misfolding can originate from translational errors at the ribosome. Indeed, the most error-prone process in gene expression is translation at the ribosome. Recent evidence indicates that manipulating the ribosomal accuracy impacts on the lifespan of model organisms and a reduced translational accuracy is accompanied by neurodegeneration. The first hit in aging-associated neurodegenerative disease may be the well-documented decline of cellular buffering capacity by aging. A second hit that impacts on the quality of protein synthesis could be the driving force for the observed loss of proteostasis in neurodegeneration. This hypothesis provides an explanation for the late onset of most neurodegenerative diseases.