Chaperone-mediated autophagy: dedicated saviour and unfortunate victim in the neurodegeneration arena.

The importance of cellular quality-control systems in the maintenance of neuronal homoeostasis and in the defence against neurodegeneration is well recognized. Chaperones and proteolytic systems, the main components of these cellular surveillance mechanisms, are key in the fight against the proteotoxicity that is often associated with severe neurodegenerative diseases. However, in recent years, a new theme has emerged which suggests that components of protein quality-control pathways are often targets of the toxic effects of pathogenic proteins and that their failure to function properly contributes to pathogenesis and disease progression. In the present mini-review, we describe this dual role as 'saviour' and 'victim' in the context of neurodegeneration for chaperone-mediated autophagy, a cellular pathway involved in the selective degradation of cytosolic proteins in lysosomes.