Proteasomal dysfunction: a common feature of neurodegenerative diseases? Implications for the environmental origins of neurodegeneration.

The neurodegenerative diseases that afflict humans affect different part of the nervous system and have different symptoms and prognoses, yet they have certain things in common. One of them is defects in the clearance of abnormal or other "unwanted" proteins, particularly affecting the proteasome system. In this review, I advance two concepts: (a) that defects in protein clearance can be a fundamental cause of neurodegeneration, and (b) that because proteasome inhibitors are widespread in nature, their ingestion may contribute to "spontaneous" neurodegeneration.