Excess protein linked to degeneration.

• Position: Parkinson's Disease - Alpha-synuclein

Overexpression of a protein called alpha-synuclein appears to disrupt vital recycling processes in neurons, starting with their terminal extensions and working its way back to the cells' center, with the potential consequence of progressive degeneration and eventual cell death, declare researchers at the University of California, San Diego. The findings have major implications for more fully understanding the causes and mechanisms of Parkinson's disease, a neurodegenerative movement disorder that affects an estimated 1,000,000 Americans.

"This is an important new insight. I don't think anybody realized just how big a role alpha-synuclein played in managing the retrieval of worn-out proteins from synapses and the role of alterations in this process in development of Parkinson's," states principal investigator Mark H. Ellisman, professor of neurosciences and bioengineering and director of the National Center for Microscopy and Imaging Research (NCMIR).

Parkinson's disease is characterized by the gradual destruction of select brain cells that produce dopamine, a neurotransmitter involved in regulating movement and emotion. Symptoms include increasing loss of muscle and movement control. While most cases are sporadic--that is, their causes are unknown--there also are inherited forms of the disease linked to specific gene mutations and modifications.

The researchers focused on one of those gene products: alpha-synuclein. Using a...