5 ms·

Dumb question (Wikipedia was of no help), if amyloid beta looks and acts like a prion, why isn't it classified as a prion?

andoband 8y ago
This is what the author was wondering at the end of the article. The discovery blurs the line between the two. There is now the question if they may be the same thing.
SlowRobotAhead 8y ago
Article: What is the difference between amyloid and prions? Are they part of a spectrum? Are they one in the same? If not, what is the difference? Can what we’ve learned about the biology of prions help our efforts to fight amyloid dementias?
sndean 8y ago
It does seem like Abeta and prions should be in the same class. A possible practical reason to keep them separated would be to avoid having various safety committees at X research institution from adding dozens of barriers to already difficult Alzheimer's research. Doing work with prions is a little like doing B. anthracis (Anthrax) research in some places - having to deal with indestructible spores. Not that those safety measures shouldn't be put in place, but it'd make Alzheimer's/Abeta research slower and more expensive. The jump from BSL-1 to BSL2+/BSL-3 is huge [0]. [0] https://blink.ucsd.edu/safety/research-lab/biosafety/containment/chart.html https://blink.ucsd.edu/safety/research-lab/biosafety/contain...
nonbel 8y ago
Amyloid-Beta is a specific instance of amyloids, while prions are a class of amyloids: >"Some amyloid proteins are infectious; these are called prions in which the infectious form can act as a template to convert other non-infectious proteins into infectious form." https://en.wikipedia.org/wiki/Amyloid https://en.wikipedia.org/wiki/Amyloid So if amyloid-beta is determined to be "infectious" (however that is done) then it would be put in the prion subclass of amyloids.
manmal 8y ago
Another dumb question: If Amyloid beta is a prion, why is it so common for Alzheimer's to occur only later in life, while teenagers can suffer from BSE? Does it have a longer incubation period?
subroutine 8y ago
There is a huge misconception about what is meant by the word "prion". Get this... there is only one (1) prion protein! All mammalian prion diseases are directly related to the PRNP gene. People talk about Mad Cow, Kuru, Creutzfeldt-Jacobs, Chronic Wasting Disease, Scrapie, and a dozen other diseases like they are not all manifestations of the same underlying problem with PRNP gene variants. People talk about "prions" as a general category of proteins capable of causing chain reaction misfolding... which is indeed what happens with PRNP variants, but not a whole bunch of different proteins -- just those transcribed from PRNP (the prion protein gene). We will probably discover that other proteins do this to some extent, but it'd still be weird to call it "a prion" because it's not a proten encoded by the prion gene. Does that make sense?
- nonbel 8y ago
  You don't share any links, but how would you reconcile this with the claims that amyloids are widespread. I posted about it here: https://news.ycombinator.com/item?id=19129157 https://news.ycombinator.com/item?id=19129157 Is it really the case that PRNP (https://en.wikipedia.org/wiki/PRNP https://en.wikipedia.org/wiki/PRNP) is the only known amyloid to be infectious?
  - subroutine 8y ago
    My comment wasn't so much on the biology, or whether other proteins could display 'prion-like' behavior; it was more so to clarify what I think is a misuse/misunderstanding of the word 'prion'. I say this as someone who perpetuated this misuse until a few months ago, after reading an article about 'prions' in the retina, and spent half the day trying to figure out what the prion protein was, only to discover there was a gene that encoded PRioN Protein (PRNP); that is, we have a specific protein called 'prion protein' PrP. So to ask whether something is a prion suggests a misconception, since that's like asking "is insulin a keratin?" or "is melanopsin an actin?", and the answer would be, of course not, since those are all names of different proteins. Now, asking whether some protein X has properties similar to PrP is a totally legit question (i.e. "is X prion-like?" = great question; "is X a prion" = probably a misconception).

andoband 8y ago

This is what the author was wondering at the end of the article. The discovery blurs the line between the two. There is now the question if they may be the same thing.

SlowRobotAhead 8y ago

Article: What is the difference between amyloid and prions? Are they part of a spectrum? Are they one in the same? If not, what is the difference? Can what we’ve learned about the biology of prions help our efforts to fight amyloid dementias?

sndean 8y ago

It does seem like Abeta and prions should be in the same class. A possible practical reason to keep them separated would be to avoid having various safety committees at X research institution from adding dozens of barriers to already difficult Alzheimer's research. Doing work with prions is a little like doing B. anthracis (Anthrax) research in some places - having to deal with indestructible spores. Not that those safety measures shouldn't be put in place, but it'd make Alzheimer's/Abeta research slower and more expensive. The jump from BSL-1 to BSL2+/BSL-3 is huge [0]. [0] https://blink.ucsd.edu/safety/research-lab/biosafety/containment/chart.html https://blink.ucsd.edu/safety/research-lab/biosafety/contain...

nonbel 8y ago

Amyloid-Beta is a specific instance of amyloids, while prions are a class of amyloids: >"Some amyloid proteins are infectious; these are called prions in which the infectious form can act as a template to convert other non-infectious proteins into infectious form." https://en.wikipedia.org/wiki/Amyloid https://en.wikipedia.org/wiki/Amyloid So if amyloid-beta is determined to be "infectious" (however that is done) then it would be put in the prion subclass of amyloids.

manmal 8y ago

Another dumb question: If Amyloid beta is a prion, why is it so common for Alzheimer's to occur only later in life, while teenagers can suffer from BSE? Does it have a longer incubation period?

subroutine 8y ago

There is a huge misconception about what is meant by the word "prion". Get this... there is only one (1) prion protein! All mammalian prion diseases are directly related to the PRNP gene. People talk about Mad Cow, Kuru, Creutzfeldt-Jacobs, Chronic Wasting Disease, Scrapie, and a dozen other diseases like they are not all manifestations of the same underlying problem with PRNP gene variants. People talk about "prions" as a general category of proteins capable of causing chain reaction misfolding... which is indeed what happens with PRNP variants, but not a whole bunch of different proteins -- just those transcribed from PRNP (the prion protein gene). We will probably discover that other proteins do this to some extent, but it'd still be weird to call it "a prion" because it's not a proten encoded by the prion gene. Does that make sense?

nonbel 8y ago
You don't share any links, but how would you reconcile this with the claims that amyloids are widespread. I posted about it here: https://news.ycombinator.com/item?id=19129157 https://news.ycombinator.com/item?id=19129157 Is it really the case that PRNP (https://en.wikipedia.org/wiki/PRNP https://en.wikipedia.org/wiki/PRNP) is the only known amyloid to be infectious?
- subroutine 8y ago
  My comment wasn't so much on the biology, or whether other proteins could display 'prion-like' behavior; it was more so to clarify what I think is a misuse/misunderstanding of the word 'prion'. I say this as someone who perpetuated this misuse until a few months ago, after reading an article about 'prions' in the retina, and spent half the day trying to figure out what the prion protein was, only to discover there was a gene that encoded PRioN Protein (PRNP); that is, we have a specific protein called 'prion protein' PrP. So to ask whether something is a prion suggests a misconception, since that's like asking "is insulin a keratin?" or "is melanopsin an actin?", and the answer would be, of course not, since those are all names of different proteins. Now, asking whether some protein X has properties similar to PrP is a totally legit question (i.e. "is X prion-like?" = great question; "is X a prion" = probably a misconception).