Yeast cells can sometimes reverse the protein misfolding and clumping associated with diseases such as Alzheimer's, according to new research from the University of Arizona (UA). The new finding contradicts the idea that once prion proteins have changed into the shape that aggregates, the change is irreversible. "It's believed that when these aggregates arise that cells cannot get rid of them," said Dr. Tricia Serio, UA professor and head of the department of molecular and cellular biology. "We've shown that's not the case. Cells can clear themselves of these aggregates." Prions are proteins that change into a shape that triggers their neighbors to change, also. In that new form, the proteins cluster. The aggregates, called amyloids, are associated with diseases including Alzheimer's, Huntington's and Parkinson's. "The prion protein is kind of like Dr. Jekyll and Mr. Hyde," said Dr. Serio, senior author of the paper published today in the open-access journal eLife. "When you get Hyde, all the prion protein that gets made after that is folded in that bad way." For yeast, having clumps of amyloid is not fatal. Dr. Serio and her students exposed amyloid-containing cells of baker's yeast to 104 degrees F (40 degrees C), a temperature that would be a high fever in a human. When exposed to that environment, the cells activated a stress response that changed the clumping proteins back to the no-clumping shape. The finding suggests artificially inducing stress responses may one day help develop treatments for diseases associated with misfolded prion proteins, Dr. Serio said. "People are trying to develop therapeutics that will artificially induce stress responses," she said. "Our work serves as a proof of principal that it's a fruitful path to follow."
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