Odd Protein May Spur Alzheimer's: Unusual Amyloid-Beta Sows Destruction in Mouse Brains
Sanders, Laura, Science News
Scientists have caught tiny amounts of a strangely shaped protein--a relative of a well-known suspect in Alzheimer's disease--spreading destruction throughout the brains of mice. If a similar process happens in the human brain, it could help explain how Alzheimer's starts and even suggest new ways to stop the disease's spread.
Many researchers believe the abundance of a molecule called amyloid-beta in the brain is a key factor in Alzheimer's disease. A-beta commonly takes the form of a chain of 42 protein building blocks called amino acids.
The new study chronicles the dangers of a modified A-beta that lacks the first two amino acids in the chain. Capping this stub is a rare, circular amino acid called pyroglutamate. Until recently, this form "has been largely ignored as some minor, mysterious form of amyloid-beta," says study coauthor George Bloom of the University of Virginia. Yet even trace amounts of this version, called pyroglutamylated A-beta, or pE A-beta, are devastating to mouse nerve cells, he and colleagues report online May 2 in Nature.
"This opens up a whole new view of the disease," says neurogeneticist Rudy Tanzi of Harvard Medical School. Instead of focusing just on the amount of A-beta in the brain, scientists need to pay attention to modifications of the molecule, too, he says.
Minuscule amounts of pE A-beta can pair up with more commonplace types and trigger them to misfold, the team reports. …