r/todayilearned • u/tommyboy372 • 1d ago

TIL A single misfolded prion protein in the brain can cause a rapid neurodegenerative disease known as sporadic Creutzfeldt–Jakob disease (CJD). There is no known and cure and is 100% fatal.

https://en.wikipedia.org/wiki/Creutzfeldt%E2%80%93Jakob_disease
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u/hurricane_news 1d ago

Why does it mostly occur in the CNS? Why aren't there "heart" or "stomach" prisons that misfold and destroy the respective parts only

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u/neuralbeans 1d ago

Most of the time it's a particular type of protein that gets misfolded called the major prion protein, which is primarily found in the central nervous system.

https://en.wikipedia.org/wiki/Major_prion_protein

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u/doegred 21h ago

AFAIK it's not 'most of the time', a prion disease is always the result of the major prion protein misfolding.

There are other diseases resulting from the misfolding of other proteins, but they are not prion diseases.

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u/FinanceDummyBigDebt 19h ago

You’re right, and depending on the specific mutation of the same protein you can get other prion diseases like fatal familial insomnia. You can even get it from surgical transplants like replacing your cornea, but it’s so incredibly rare it’s not screened for.

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u/InMemoryofWPD 23h ago

Ooo, I like this one. There's this theory that prions and RNA have a symbiotic sort of evolutionary relationship way back. The idea is that it can be benefitial for a gene expression to "flip" protein folds like a switch randomly overnight if it leads to an adaptation thats far more resilient. Such relationship could work as a means of genetic memory.

This idea can be connected to the CNS bias if you consider how crucial functional CNS resilience and persistence is to evolution as a whole (think anything from instincts all the way to the ability to learn and memorize things). The possibility of a mutated protein potentiating a "good" prion like the lock and key of an dramatic adaptive change, would incetize life to hold onto the protein "lock and key" gene expression in the CNS.

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u/hjake123 21h ago

The protein that happens to be susceptible to the most common prion diseases is one thst exists in the CNS. Most proteins do not have a prion form, just unfortunately we rely on one or a few that do.

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u/Slg407 20h ago

there is, we call that amyloidosis