Printer Friendly

Huntington's protein may be kidnapper.

Huntington's disease, a neurodegenerative disorder affecting 250,000 Americans, is a case of biochemical woe. Tangles of protein collect in brain cells. The tissue dies, leaving gaping holes in people's brains. But the protein--dubbed huntingtin--doesn't kill cells directly. Instead, it kidnaps another protein essential for cell survival, researchers report in the March 23 SCIENCE.

Christopher A. Ross of Johns Hopkins Medical School in Baltimore and his colleagues demonstrated in a test tube how huntingtin contributes to cell death. The scientists were also able to halt the process, saving doomed human cells.

Huntington's disease is a fatal disorder that begins in midlife and eventually destroys muscle control and cognitive abilities. It's caused by a single mutated copy of the gene for huntingtin. The damaged gene makes a version of the protein with an unusually long chain of one of its components, the amino acid glutamine.

Instead of folding into a functional protein, chains of glutamine on the mutant huntingtin molecules stick to each other. These build up in plaques inside brain cells. Similar plaques collect in the brains of people with Alzheimer's disease, but the role of the plaques hasn't yet been determined.

"Surely, it's not good for cells to have glop clogging them up," but the clumps of huntingtin haven't appeared to be directly toxic to cells, says Ross. For example, he notes, the brain cells most likely to die in people with Huntington's disease aren't necessarily the ones containing the protein deposits.

The researchers wondered whether mutant huntingtin proteins might pose indirect harm by binding to short glutamine chains in other proteins in the cell. This would pull important proteins out of service and block their normal function.

One candidate protein for this process is known as CBP, or CREB binding protein, which is central in the biochemistry of cellular survival. The team found that brain samples from people who had died from Huntington's disease, as well as mice with a similar syndrome, had very low amounts of CBP, suggesting that the protein had been sequestered in huntingtin plaques.

The researchers also grew brain cells that produced abnormal huntingtin and found that these also kidnapped CBP. When they added CBP molecules that were missing their strings of glutamine, the molecules didn't collect in deposits and the cells survived.

Now that the researchers have rescued brain cells in laboratory dishes, says Ross, their next task, says Ross, is to do the same in living mice.
COPYRIGHT 2001 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2001, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science News
Date:Apr 28, 2001
Previous Article:When parents let the kids go hungry.
Next Article:Worm sperm stimulate ovulation.

Related Articles
Some neurons predisposed to Huntington's.
Molecules bind mutant Huntington proteins.
Huntington's accomplice captured?
Nuclear buildup may explain brain diseases.
Let's repeat: mutation gums up brain cells.
Thwarting killer enzymes of the brain.
Cancer drugs may thwart Huntington's. (Biomedicine).
Slow brain repair seen in Huntington's. (Stem Cells).
Drug limits disease effects in laboratory mice. (Huntington's Advance).
Might a simple sugar derail Huntington's?

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |