Protein quality control mechanisms and neurodegenerative disorders: Checks, balances and deadlocks

Neurodegenerative disorders are a group of hereditary and sporadic conditions that are characterized by progressive nervous system dysfunctions. These disorders are often associated with neuronal atrophy and are characterized by the presence of intra- or extra-neuronal inclusions in the central or peripheral nervous system. The emerging understanding on these apparently diverse set of disorders suggest that they share a few key pathomechanisms, one of which could be the abnormality in the protein quality control pathways. Recent studies have shown that either an overload on the proteolytic pathways - the ubiquitin-proteasome system and the autophagosome-lysosome system - or defects in the critical components of these pathways might underlie the neuropathology. Here, we review the recent advances in our understanding on the role of protein quality control systems in the pathomechanisms of neurodegenerative disorders, highlight the interdependence between the two pathways and their involvement in neuronal survival.