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9

If we are considering prions in general, I disagree with the answer supplied by Gerardo Furtado. Here is a definition taken from an article by Susan Lindquist: [Prions are]...self-perpetuating and heritable protein conformations that cause multiple phenotypes, represent an unusual mechanism of information transfer that occurs via protein instead of ...


7

Knock-out experiments on non-pathological prion proteins ("PrP") show damage to neurons. So there is evolutionary pressure to conserve their sequence and expression. Mutations to PrP and related regulatory regions appear to be deleterious and the organism will not likely get to reproduce. A paper here explores this question and demonstrates empirically that ...


7

Amyloids are protease resistant insoluble fibrils formed because of (mis)folding and aggregation of soluble proteins (Rambaran and Serpell, 2008, Sabate et al., 2015). The first definition of prion was given by Prusiner (1982): Because the novel properties of the scrapie agent distinguish it from viruses, plasmids, and viroids, a new term "prion" is ...


7

Prions are misfolded proteins with abnormal tertiary or quaternary structures. That grants them resistance (to some extent, at least) to proteases (1). Also researchers believe that prions are able to replicate (2), by changing the structure of other proteins. Regarding the gastrointestinal barrier, that isn't exactly true. It has been shown that small ...


6

The computational study by Ehsani et al., 2011, argues that an ancestor metal-ion transporter gene ZIP served as the initial template for the prion founder gene, where the same author produced a 2012 paper that said this was probably a product of a spliced LIV-1 ZIP transcript that became reverse transcribed and inserted into the host genome. Thus, evidence ...


4

Update: note that prion-like proteins have now been discovered in Archaea. Note that prion proteins are an important component of yeast natural history. If they are shared between yeast, amniotes, and Archaea (which branched off at least a billion years ago), one could argue that prions are: Extremely ancient (>1 billion years since that split). a ...


4

Prions are proteins that we produced but that are misfolded and affect the folding of other proteins. As we produce these proteins, we don't recognize them as antigens. If we were to recognize our own proteins as antigens, then the immune system would constantly be fighting against ourselves. This is what is called a autoimmune disease. While this was a ...


4

I am not sure if a perfect answer is possible owing to the fact that Prion diseases are still incompletely understood, and are actively under research. On a preliminary search, I found some papers which address the issue (cited at the end). Since $PrP^C$ is normally found in the body, its role and its transport is also relevant to the issue. It seems to ...


3

My understanding is that the principal quality of a prion is that it behaves like a prion in cells- the logic is a little circular. A few of these criteria for acting like a prion (in yeast, where prions are most common): Reproduces itself by "templating" (refolding of non-prion versions of itself into prion versions) Sensitive to protein denaturing ...


3

Just my speculation here. Prions seem to need some sort of template to guide their folding as well as the cooperation of chaperone proteins. https://en.wikipedia.org/wiki/Prion I would suspect that denaturing, and potential re-folding, of proteins during cooking would be rather random. So even if one, or very few, copies of a potential prion happened to be ...


2

Dr Yong in the paper titled Prion, The unconventional slow Infectious agent states that the formation of amyloid plaque which is a major contributor to Alzheimer's disease is a unconventionally slow infectious disease (Prion). Some papers have also pointed out the similarities between Alzheimers and prion disorders (reference) Cerebral amyloid plaques have ...


2

Some of the processes working against cannibalism: conspecifics (especially similar-aged conspecifics) are likely to be able to fight back effectively, increasing the risk of injury to the would-be cannibal for organisms with limited dispersal, nearby conspecifics are likely to be closely related; killing them will decrease inclusive fitness possible spread ...


2

First, to be clear, the very act of cannibalism does not cause the development of prions, but the consumption of an animal infected with a compatible form of them, particularly when eating nervous or digestive tissue (i.e. the brain, spine, stomach, or intestines). To directly answer your question, yes, there are other animals that are susceptible to prions ...


2

The Wikipedia definition of prions is quite clear I think: Prions are infectious agents composed entirely of a protein material that can fold in multiple, structurally abstract ways, at least one of which is transmissible to other prion proteins, leading to disease in a manner that is epidemiologically comparable to the spread of viral infection. ...


2

If the amino acid sequence of both proteins is the same, what determines whether the synthesized protein will take the disease-causing tertiary structure or the normal one? PrP-C and PrP-Sc do indeed have the same primary structure. However, they differ in secondary and tertiary structure. The protein can take more than one shape (conformation), where ...


1

There are many prions other than PrP; it is often helpful to e.g. read wikipedia for these cases. For example, there are many yeast prions that are not homologous to PrP https://en.wikipedia.org/wiki/Fungal_prion. But even in humans there are a number of other proteins that form amyloids and are described as "prion-like" even though they aren't the ...


1

Yes, malformed prion proteins can affect tissues outside of the brain. Via: https://www.merckmanuals.com/home/brain,-spinal-cord,-and-nerve-disorders/prion-diseases/overview-of-prion-diseases Another familial prion disease has been recently discovered. It differs from other prion diseases because it causes diarrhea and affects nerves throughout the body ...


1

The notion that you get prion diseases like BSE only by consumption of brain is not correct. Any part of the infected animal that contains nervous system tissue or lymphatic tissue can be infectious, although I guess this is dose-related. Quote from OIE, "BSE. General disease information sheet" ([1]): The risk linked with consumption is addressed by the ...


1

It is thought that infectious prions exist as clusters forming a crystalline structure. When a protein with the same primary structure is encountered but with a different tertiary structure, the normal protein undergoes a conformational change in order to integrate into the cluster. Presumably there are molecular forces involved that induce the ...


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