Talking About Prions Some More

Pursuant to my post yesterday on prion diseases, commenter "Nobody" writes:

I am unfamiliar with this "good prion" you speak of. Prions are misfolded proteins that either interfere with the folding of other proteins or allosterically alter them.

So, the "good prion/bad prion" bit was an overstatement. Here's what I was getting at, from the National Institutes of Health (which, by the way, agrees that prions are real and cause TSEs):

Prions enter brain cells and there convert the normal cell protein PrPC
to the prion form of the protein, called PrPSC. When normal cell proteins transform into prions, amino acids that are folded tightly into alpha helical structures relax into looser beta sheets. More and more PrPC molecules transform into PrPSC molecules, until eventually prions completely clog the infected brain cells. The cells misfire, work poorly, or don't work at all.

Point I was trying to make—perhaps ineptly—was that as I recall, the original theory was that prions got in your head and killed you up good, but then it turned out that everyone already had prion-like proteins all the time. So Prusiner—again, I may be misremembering this—modified the theory to account for "normal" noninfectious prion proteins and twisted, bad prion proteins.

Am I way off, here?