http://www.sciencedaily.com/releases/2010/09/100908094924.htmScienceDaily (Sep. 7, 2010) — Chemists at the University of California, San Diego, have identified how a protein that accumulates in the brains of people with Alzheimer's disease interferes with the ability of cells to get rid of debris. They also found a natural mechanism by which this protein, amyloid beta, itself may be discarded.
"Basically the trash is put out to the curb, but no one is picking it up," said Jerry Yang, an associate professor of chemistry and biochemistry who led the research effort.
Yang and postdoc Xiaobei Zhao showed that amyloid actually doesn't harm the proteasome. Instead it interferes with the processing of other proteins by competing for access, they report in a forthcoming issue of the journal ACS Chemical Neuroscience.
They found that the proteasome breaks long chains of toxic amyloid into smaller, harmless pieces. And because the proteasome has a greater affinity for amyloid, other proteins build up undigested.
"The fact that the proteasome can hack up amyloid fairly efficiently gives us some insight as to how normal clearance mechanisms actually work," Yang said. "We all have amyloid peptides, and we all get rid of them as well. The proteasome is in every cell."