Who hasn’t heard of mad cow disease? Maybe there are a lot more diseases like that than we recognize — such as Parkinson’s, Alzheimer’s and Huntington’s — that are caused by a rogue, mis-folded piece of protein that seeds other bits of protein to mis-fold as well.
So argues Stanley Prusiner, a UC San Francisco professor, ina commentary in the journal Science.
Prusiner won a Nobel Prize for finding that a class of neurodegenerative diseases (of which mad cow is one) is caused by such infectious proteins, dubbed prions. Diseases in this class include Creutzfeldt-Jakob Disease, which occurs sporadically, as well as a few inherited disorders, such as Gerstmann-Straussler-Scheinker syndrome and fatal familial insomnia.
In animals, the class includes mad cow (more properly called bovine spongiform encephalopathy or BSE), scrapie in sheep and chronic wasting disease in elk.
And then — in humans again — there’s variant Creutzfeldt-Jakob Disease, the type scientists think was linked to consumption of BSE-infected beef.
In all those cases, the rogue is a mis-folded protein called PrP.
But there are many other diseases of the brain in which plaques or tangles of proteins build up. Could some of these also be caused by rogue, self-propagating proteins?
In Alzheimer’s, for example, plaques of a protein called beta-amyloid accumulate in brain cells.