Talk:Prion/Archive 2

Delivery of prion across the BBB
I'm no expert on this issue, so may I ask how is the protein delivered through the blood-brain barrier to get into the brain? Or is it still not figured out yet? LHcheM (talk) 03:50, 7 September 2012 (UTC)

Pronunciation
I'm not sure if we should specify only one pronunciation in the article. As much as some people are absolutely sure about this, IMHO it shouldn't be the same as that for "preon". Further, "when two vowels go walking, the first does the talking"; a little ditty which English-speaking folk should remember from grade-school. Also, the "pry'-on" pronunciation was in use years ago already, so I have a hard time believing it is wrong even if it has to share the choice of pronunciations in a dictionary. - KitchM (talk) 05:09, 3 February 2010 (UTC)


 * I've seen Stanley Prusiner make a point about the pronunciation before, so I'd suggest keeping the "one true pronunciation." --Dpryan (talk) 00:31, 4 February 2010 (UTC)

SO many of you guys are so terrified of hard vowels! Given that the "ion" part is from "infection", how can it be anything other than "preon"? And don't get me started on "Eyemax" for Imax, which is a contraction of "Image Maximum", not "Eyemage Maximum". 124.183.244.117 (talk) 11:27, 24 August 2012 (UTC)


 * Etymology is by no means omnipotent. And note that in /ɪnˈfɛkʃən/ the second "i" is silent! By your rationale, the pronunciation of prion should be PRON (/ˈprɒn/; or even /prən/)... Not very logical. The Merriam-Webster dictionary gives only one pronunciation, \ˈprī-ˌän\   (i.e. /ˈpraɪ(ˌ)ɒn/) which is much more regular and therefore, in my humble view, preferable.  http://www.merriam-webster.com/dictionary/prion    The Random House Webster's Dictionary on the other hand shows both pronunciations, in this order: /ˈpriːɒn, ˈpraɪɒn/. Both dictionaries are very authoritative in these matters.Viktor Laszlo (talk) 13:15, 31 January 2013 (UTC)

Self-Replication
How is it that prions do not self-replicate? It's not like DNA singularly reconstructs copies of itself from constituent molecules. Virtually nothing recreates itself from basic components without the aid of environmental machinery, including DNA. Under what I infer the definition of self-replicating to be from the article's usage, I conclude that only self-catalyzing RNA such as Spiegelman's Monster are actually self-replicating. Moreover, the article on self-replication lists prions as an example! —Preceding unsigned comment added by 76.173.186.135 (talk) 06:51, 22 May 2010 (UTC)
 * Even the monster requires RNA replicase... —Preceding unsigned comment added by 76.173.186.135 (talk) 06:53, 22 May 2010 (UTC)


 * Agreed. Every cell from microbiology to animal iz all part of one big machine, and nobody haz witnessed the creation of life. Amino acids? Yes. Nucleic Acids, even. But make them work together? Not seen. Oops. There is a blue bacterium that someone created from scratch. Whether it is compatible with life on Earth iz another question, since they put a lot of extraneous DNA into it, just because they could. 142.59.231.219 (talk) 07:01, 12 March 2012 (UTC)

Proposed new section of prion replication mechanism
Earlier I deleted one of the figures, of the heterodimer model of prion propagation, because it was not supported by the data. I think it is important to put back something more about the replication mechanism. I have written a draft of a new section, which I think would fit in very naturally between the Structure and Function sections. I included both the old figure that I deleted, and a new one. I don't know how to format figure size, could somebody please help? Also any other changes/suggestions before I insert this section into the real page.Joannamasel (talk) 17:28, 29 August 2010 (UTC)


 * The "heterodimer" diagram wasn't intended to literally represent a dimer - it is just meant to be a broad representation of PrPC interacting with PrPSc or whatever the infectious form actually is. It definitely wasn't intended to mean the dimer would then split into two again. The section doesn't entirely make sense as it is - it says that the heterodimer model would require PrPSc to be an amazing catalyst, but then the fibril model described would still require PrPSc to convert PrPSc, so there's really no difference between them. I think this section is overcomplicated - it would better to have one diagram. Theres no need to mention fibrils, and it doesn't have to mention PrPSc, as you can have prion diseases without either of those being present. If you really want to go into detail, the 2 main contenders for mechanism have traditionally been template-assisted conversion and nucleation-polymerisation. Purple  23:38, 2 December 2011 (UTC)


 * I think that the fact that prions require an oligomeric form is notable, and this is easier to explain by means of a contrast with an alternative model. There is a range of evidence pointing to some kind of fibril as this form. I tried to clarify the section you found confusing, and how cooperativity makes the two cases different: you can find more details in Eigen's paper. Most of the literature on nucleation-polymerisation concerns in vitro work. (Primary) nucleation is obviously not part of the process of a disease acquired a single time by infection. I think the article should focus on in vivo replication as far as is practical.Joannamasel (talk) 00:49, 3 December 2011 (UTC)

Image needed
Need some 3d images of prions. --68.91.94.192 (talk) 21:54, 7 October 2011 (UTC)

See PrP. I suppose there are two articles on the same thing, because this article got too big. 137.186.47.81 (talk) 17:28, 9 March 2012 (UTC)

Alzheimers caused by prions?
Research is showing alzheimers might be caused by it.--68.91.94.192 (talk) 21:54, 7 October 2011 (UTC)


 * That iz not news to me. The unifying symptom iz amyloidosis.

137.186.47.81 (talk) 15:16, 4 March 2012 (UTC)


 * See also "| Prion-like behaviour and tau-dependent cytotoxicity of pyroglutamylated amyloid-β" (Nature 485, 651–655 (31 May 2012)). I'm not sure how to incorporate this into the article. Speedyboy (talk) 01:31, 31 May 2012 (UTC)


 * Actually, there is some resemblance in that there is a protein involved, but there is no evidence of infectious properties and no papers describe it as a "prion". Beware of the media hype and analogies. Cheers, BatteryIncluded (talk) 17:59, 1 October 2015 (UTC)


 * Correct. No one has ever identified prions in the brain tissue of Alzheimer patients -- and they've looked, believe me. The fact that there are "clinical similarities" between prion-caused diseases and Alzheimer's in no way proves that they have a common etiology, and the histopathology is entirely different. How to incorporate this into the article? Don't.  DoctorJoeE  review transgressions/ talk to me!  18:08, 1 October 2015 (UTC)

Is it alive?
Given all that it does, is it reasonable to regard the prion as alive; ie, that it is a lifeform in its own right? I'm not pushing either answer, simply looking for arguments either for or against. Old_Wombat (talk) 09:47, 24 January 2012 (UTC)


 * No. I believe Gajdusek's 'Ash of Hamster' experiment proves more than he claimed in his title: The cause of scrapie iz inorganic. Even viruses need both DNA and protein, and by themselves they are dead and dormant, only to come alive when they get access to a cell with the rest of the minerals and energy needed to replicate. 142.59.231.219 (talk) 06:55, 12 March 2012 (UTC)


 * Wikipedia sticks to the peer-reviewed literature. We can talk about Gajdusek's interpretation of Gajdusek's experiment, but your own personal interpretation of his experiment is OR. Joannamasel (talk) 15:12, 12 March 2012 (UTC)

No such thing az PrPC iz.
No such thing az common protease resistant protein egzists. If such a thing wuz, then we would all hav Alzheimer's. This acronym iz a lie. Delete it, and replace it with "a protein that can become protease resistant", or just "a protein" or "amyloid precuror protein (APP)". 137.186.47.81 (talk) 15:06, 4 March 2012 (UTC)


 * The name of the gene/protein is PrP. It doesn't matter what this originally stood for, although for the record, it stands for prion protein, not protease resistant protein, something made quite clear in the article. In any case, PrP is now its name. It is defined by its amino acid sequence, or homology thereto. You cannot change that fact on a wikipedia page. Amyloid precursor protein is a completely different protein. You cannot substitute that in. Nor can you substitute in generic reference to a protein. PrP is a particular protein, and PrPC is the accepted term for one form of that particular protein. I will revert your changes, please do not edit again without first getting consensus for this very major change on the talk page. I am also reverting changes to the heavy metal poisoning hypothesis section. No reason was given for the deletion of existing material, and the material you replaced it with is not supported by the accompanying references. Joannamasel (talk) 00:40, 5 March 2012 (UTC)


 * Moreover, the amyloid precursor protein (APP) is a completely different protein (sequence and structure) from PrP. APP is (as the same suggests) the precursor protein from which the beta amyloid peptide is cleaved; the disease for which it is reasponsible – Alzheimer's – has never shown any sign of being susceptible to prion transmission. That said, we should probably look at the way the material in the 'Structure' and 'Function' sections is presented; there's a lot of material that's specific to mammalian PrP that probably shouldn't be in this more-general 'prion' article.  TenOfAllTrades(talk) 02:16, 5 March 2012 (UTC)


 * I am sorry that I did not believe you in the first place. It would've helped if you had noticed that someone else on this page did not realize that PrP is a different article from prion. Owing to redirections, it happens that they could be the same article. 137.186.47.81 (talk) 20:09, 9 March 2012 (UTC)


 * Material on the structure haz been deleted, because it would detract from what haz become the point of the article: It contains too much dissent, and it iz too overwhelming to actually believe in an infectious protein, so drawing pictures of it became offensive. No clear evidence of an infectious protein exists, and Gajdusek offers convincing evidence that the cause of CJD iz inorganic. Alzheimer's and CJD cannot be easily distinguished. Both of them rezult in a smaller brain with holes and amyloid plaques. An old version of this article (probably with pictures) lists the other "prion diseases", including other species, Alzheimer's among them. I put my bit in here to illustrate that yes, indeed, my references support my statements. I deleted the section az it wuz, because it did not clearly support the manganism hypothesis. I can barely read it az it iz. I do not accept PrP to mean prion protein. The coroner's test of amyloidosis iz protease resistant protein, although there are probably many other tests and stains. PrP and APP are identical: See the link to amyloidosis. 137.186.47.81 (talk) 16:14, 5 March 2012 (UTC)


 * Perhaps you've been confused by the suggestion (for which at least some evidence does exist) that the major prion protein PrP may be a membrane receptor for the beta amyloid peptide? As long as you're hung up on basic factual errors like equating APP and PrP you're not going to be able to understand the literature, and I'm afraid there's not a lot I can do to help you.
 * In any event, could take a little more time to proofread your posts? The chronic misspellings are extremely distracting.  TenOfAllTrades(talk) 17:24, 5 March 2012 (UTC)


 * My "misspellings" are literal and intentional. I am primarily a linguist. I know what schwa iz. The people who write pronunciations into wikipedia do not.


 * I looked around with the question "how does anyone know that PrP and APP are different". I did find an interesting article, and it did not answer my question. http://everything2.com/title/The+prion+protein+as+a+receptor+for+amyloid-beta It wuz a whole lot easier to read than anything Prussiner writes, though. Perhaps you can find something that explains this basic understanding you have, because az far az I know, basic understandings come from wikipedia. 137.186.47.81 (talk) 17:34, 5 March 2012 (UTC)


 * Meanwhile, this gets 88 hits:

http://www.ncbi.nlm.nih.gov/pubmed?term=PrP%20amyloid%20plaque


 * The 'basic understanding' that APP and PrP are different proteins is readily apparent from their respective Wikipedia articles, to which I've already linked. I'm seriously concerned that your recent edits to this and other disease-related articles are not backed by a sufficient background competence in biochemistry and medicine, and your confrontational attitude (insisting that you be spoon-fed and tutored, and that other editors put up with your deliberate obfuscation of your language) disinclines me to expend the effort to deal with that deficit. TenOfAllTrades(talk) 04:42, 6 March 2012 (UTC)


 * If you do not feel like doing the research, it iz nice of you to say so, and don't blame me: Do not spend more time arguing with me than with my points. Both are involved in amyloidosis. APP and PrP will both bind with copper. So, what happens in vivo? Do they fight for copper? Or iz one protein part of the other, so that some large structure, like an ionophore can decide whether a cell needs more copper? This issue is a side issue. My section on Manganism is far less obfuscatory than what iz already there. What iz there begs relevance. 137.186.47.81 (talk) 11:08, 8 March 2012 (UTC)

Btw, this guy^ is a troll, don't bother replying. - M0rphzone (talk) 08:33, 26 April 2012 (UTC)

Heavy metal poisoning hypothesis
Ash of Hamster transmits encephalopathy. Two of those suggest neither protein nor D.N.A. as an agent of disease, and allow an inorganic material such as Manganese to cause scrapie. This agrees with epidemiology in which Manganese concentrations at scrapie-affected sites were 2.5 times those of adjoining areas. (deleted by author, 26 March 2012) It also agrees with Manganese polymerizing normal prion, which is therefore proteinase resistant. Manganism readily allows spongiform encephalopathy to cross the species barrier.

The Gajdusek paper you cite is certainly a provocative and controversial one, but it does not claim to eliminate protein as a vector. Incineration to 600C massively reduced infectivity, even though it did not eliminate it altogether. The authors hypothesize that the core fact about a prion is its shape. While it is NORMALLY A PROTEIN that takes this shape, they hypothesized that it is also possible for inorganic ash to retain an imprint of the shape that a protein previously held, and so act as an inefficient template for future protein conversion to restore the presence of prions. I would be happy to see this paper covered in the prion article, but your text is not consistent with the authors' claims. In contrast, manganism is a fringe theory, and does not belong on this page at all. Joannamasel (talk) 16:05, 8 March 2012 (UTC)


 * You hav two peer-reviewed, pubmed-listed articles to classify as fringe theory. This is one: http://www.ncbi.nlm.nih.gov/pubmed/8912903 The other one is about manganese-catalyzed polymerization. 137.186.47.81 (talk) 15:01, 9 March 2012 (UTC)


 * The article you link to here does not mention prions, and so does not support your point.Joannamasel (talk) 19:29, 9 March 2012 (UTC)


 * That does not follow. It mentions amyloidosis. The reason someone thinks that prions can deform prions is because proteinase resistant protein is involved in amyloidosis. 137.186.47.81 (talk) 19:56, 9 March 2012 (UTC)


 * Plenty of articles relevant to prions that do not mention prions can be found on Pub Med with a search for scrapie: http://www.ncbi.nlm.nih.gov/pubmed?term=(scrapie)%20NOT%20prion 142.59.231.219 (talk) 03:31, 11 March 2012 (UTC)


 * Two transmissions at 600C is a containment failure, and the dose of 0.03mL iz too small. I would like to see the experiment done with oral feeding, too. I've read that it was done before 2000, and I just don't know the right search terms.


 * It is unfortunate that the authors chose so many words, and a conservative estimate of what their evidence means in their title. It is also unfortunate that Gajdusek said anything about "hamster-adapted scrapie agent" before he said anything about "inorganic". It is easy to explain 600C, and I do wish they had used lower temperatures and longer periods of incineration. When Wood Ash is burned at 600C, many of the trace metals vaporize. When you add all of my citations together, Manganism iz not a theory, and the remaining text in that section is still not related to a heavy metal poisoning hypothesis. Ash of Hamster transmits encephalopathy. It does not contain carbon. I wish the authors had analyzed their ash for protein molecules. At the temperatures they were using (six times boiling), I would not believe complete molecules of any protein, and it would not hurt to be sure. 137.186.47.81 (talk) 11:45, 9 March 2012 (UTC)


 * Wikipedia sticks to the peer-reviewed literature. We can talk about Gajdusek's interpretation of Gajdusek's experiment, but your own personal interpretation of his experiment is OR. Similarly, there may be peer-reviewed evidence that manganese increases the prevalence and/or severity of prion diseases. This does not mean that the infectious agent is inorganic manganese or inorganic anything else: such a conclusion not present in the primary literature is, again, OR. There is widespread agreement in the peer-reviewed literature regarding that the infectious agent includes PrP protein. Joannamasel (talk) 15:17, 12 March 2012 (UTC)


 * It's difficult to respond to your posts, anonymous editor (137.186 & 142.59) as you keep adding and removing text. Generally it's a bad idea to edit a signed, dated message more than a few minutes after it goes up, because other editors may find themselves replying to content that is no longer there, and third parties may find the course of the discussion confusing to follow.  If you find that you have something that you would like to add to a previously-posted message, just add a new supplementary remark to the discussion, under a new date-stamped signature, so that it's clear who said what, when.  If you want to withdraw a remark, either add a new comment simply saying so, or strike through the text that no longer applies (adding a new dated signature and notation to the end of the comment indicating when your edit was made, possibly in small type .)
 * 8912903 (Schmechel et al., 1996) isn't about prion disease, it's about beta-amyloidosis. We've covered this point many times before&mdash;not all amyloid is prion (indeed, most isn't), and the beta-amyloid peptide is not PrP.
 * 22007749 (Hesketh et al., 2012) discusses a way to induce the infectious prion conformation of PrP in vitro using manganese. While it is an interesting result – and it is scientifically useful to have a reproducible, reliable way to induce to prion conformation on the benchtop – it is a long way from confirming that this is the way that prion particles are actually formed within living organisms.
 * 10790765 (Purdey) is a 2000 paper from Medical Hypotheses. Honestly, it's just not a good journal, and one which (at that time) didn't use external peer review; paper acceptance was based on the editor-in-chief's judgement, and stuff tended to go in as long as he found it interesting.  For decades, Medical Hypotheses has been the go-to journal for AIDS denialism, anti-vaccination crackpots, and so forth.
 * 10716712 (Gajdusek's original 2000 paper) is one of those special 'Contributed by' papers in PNAS. Members of the Nation Academy of Sciences (like Gajdusek) are allowed to 'contribute' a limited number of their own papers each year to PNAS.  Unlike the normal 'direct' submissions to PNAS, the individual submitting a 'contributed' paper chooses his own peer reviewers for an article, and submits those selected reviews to PNAS along with the manuscript.  The advantage of this system is that it can allow senior, experienced scientists to present work that would otherwise be too controversial for a major mainstream journal; the disadvantage is that sometimes this process leads to the publication of utter crap.  (Mostly such papers end up somewhere in the middle, neither egregiously bad nor earth-shatteringly good; it's just a way for Academy members to get their ho-hum manuscripts into a higher-impact journal than would otherwise be possible, with a relative minimum of fuss.)  Consider Table 2 from the Gajdusek paper, in which hamsters were inoculated with scrapie-infected tissue that had been pretreated in various ways.  Five minutes at 600&deg;C seems to produce complete inactivation of the infectious particles&mdash;zero of eighteen hamsters exposed to this material developed disease.  On the other hand, fifteen minute at 600&deg;C failed to inactivate the prions, and five of eighteen hamsters in this category were infected.  It's a very short and inconsistent peg on which to hang a conclusion.
 * What is missing is the 'smoking gun': a straightforward study wherein animals exposed to manganese develop a TSE, and animals not receiving manganese do not. (Bonus points awarded for doing a proper dose-response curve.)  TenOfAllTrades(talk) 16:59, 12 March 2012 (UTC)
 * Purdey's epidemiology is a smoking gun, without the lab conditions. Someone did a study that used scrapie agent, Manganese, and Copper, and they found that manganese-rich and copper-poor diets increased intoxication. I see no problem with interpreting a Copper to Manganese ratio (most of the epidemiology I can find uses a confusing Iron to Manganese ratio), and they should've eliminated the confounding variable: scrapie agent.
 * Now, what I find perplexing, is that all of the sections under debate would be classified as fringe theory, and what's being demanded here for just one of them is not evidence, but proof that all of the other research on prion, including Prussiner's tobacco-funded, nobel-prize winning gospel, is sloppy.
 * I will grant that Medical Hypotheses haz not always undergone rigorous peer review,, and rather than demand a fact check, I've done it myself, for my opponent. That may be in MH's favour regarding Mark Purdey. He was just an organic farmer. Peer review would probably hav been denied him, owing to the learning curve on biochemistry.
 * As far as Gajdusek was concerned, in making a long title, he introduced a concept that was palatable to his reviewer; that prions are a replication process, and not a simple ionic deformation of protein. F. Zhu demonstrated that Manganese and Copper cause predominantly different conformations of prion. There are reasons to take wordiness and equivocation out of titles. If the experiment does not support a replication process, then that concept naturally disappears. I will add that according to a book I read, Gajdusek did not like it when Prussiner introduced a new word, and he followed up on what is probably the sharpest piece of research (it was done before it was in pub med) against the concept of an infectious protein. I will say again, that it's too bad he used temperatures as high and periods of incineration as low as he did. He could've failed to replicate the third piece of research. Gajdusek is replicated research, though, so it won't disappear. You can argue about how it is interpreted. 137.186.41.154 (talk) 13:01, 26 March 2012 (UTC) There are no facts, only interpretations. --Friedrich Nietzsche
 * Please don't delete material from your old comments, and please don't hang extra, unindented quotes off the end of your posts. This is at least the second time you've been asked not to make substantial edits to older comments, as it can confuse subsequent readers (who will wonder why editors are responding to points no longer present).  In the discussion above, your deletion made it look like I brought up Purdey's paper, rather than you.  Adding unindented, superfluous quotes both distracts from the discussion at hand, and makes the conversation more difficult to follow.  I've restored the comment that you deleted (with a strikethrough, as you were previously instructed) and moved Nietzsche back up on to the same line as the rest of your comment.  TenOfAllTrades(talk) 17:32, 26 March 2012 (UTC)

How differs APP from prion?
Please put your answer here 137.186.47.81 (talk) 17:12, 9 March 2012 (UTC)


 * It's very simple. A protein is defined by its amino acid sequence. APP and PrP are the names for two proteins, that have totally different amino acid sequences. Joannamasel (talk) 15:59, 8 March 2012 (UTC)


 * Maybe I can believe you, and I can't believe the guy who is trying to tell me that prions and PrP are different. They are different articles; different aspects of the same thing. That was my biggest problem. I did not follow a link to PrP, because I thot it was a redirection to prion. 137.186.47.81 (talk) 20:04, 9 March 2012 (UTC)


 * Prion is a general term for proteinaceous infectious particles (or diseases caused by those particles like Scrapie), and PrP is a prion protein's name. PrP is currently the only prion protein found in mammals, but many other prion proteins (Sup35, Ure2, Rnq1, Swi1, Mca1, etc) have been identified in fungi, especially Saccharomyces cerevisiae. So "PrP and prions" is sort of like "APP and amyloidogenic proteins" (APP is an amyloidogenic protein) or "APP and Alzheimer's disease" (Alzheimer's is the disease caused by APP). Although PrP and APP are both amyloidogenic and pathogenic, the two proteins are completely different in primary structure and are thus responsible for different diseases, namely prion diseases and Alzheimer's disease. --Occhanikov (talk) 12:27, 26 March 2012 (UTC)


 * It's nice to get more information than I am asking for, eventually. 137.186.41.154 (talk) 13:04, 26 March 2012 (UTC)

Sentence makes no sense.
"(Note that the propagation of the prion depends on the presence of normally folded protein in which the prion can induce misfolding; animals which do not express the normal form of the prion protein cannot develop nor transmit the disease.)"

How can any critter NOT have its normally folded protein? And conversely, if an animal does not express its normal form, what does it express? Very confusing. Can someone who KNOWS explain, or expand this? 124.183.244.117 (talk) 11:22, 24 August 2012 (UTC)
 * This sentence does make sense. The prion protein PrP can form not only the normally folded structure but also amyloid aggregates (whose monomer's structure are called "amyloid"/"abnormal" form of the prion protein), which can be acquired though misfolding by stress or point mutation. The amyloid aggregate of PrP then binds to and autocatalytically misfold another normally-folded PrP molecule, thus elongating itself. Since the amyloid aggregates was originally expressed as a normally-folded protein from the host's genome, the expression of normally-folded PrP is a must in order to elongate the PrP amyloid seed that must be taken from the external environment. --Occhanikov (talk) 12:36, 24 August 2012 (UTC)

Thank you for your very quick reply, but it doesn't address my misunderstanding. It is the second part of the sentence that to me seems senseless: "animals which do not express the normal form of the prion protein".

Maybe a lateral approach. Can you give me an example of "animals which do not express the normal form of the prion protein"? 58.170.1.58 (talk) 09:36, 25 August 2012 (UTC)
 * PrP-deficient mice and cattle (whose PrP coding genes are artificially deleted so that they simply don't express it) are examples of those that do not express the normal form of PrP. They are immune to PrP-related spongiform encephalopathies because they can not express PrP monomers to elongate the prion amyloid. This phenomenon is also observed in yeast prions. By the way, I probably understand your confusion, for the sentence technically should just be "animals which do not express the prion protein." Point mutations in PrP coding gene can cause a failure in the formation of normally folded PrP, but can sometimes result in more efficient propagation of prion disease. --Occhanikov (talk) 10:23, 26 August 2012 (UTC)
 * Worth noting as well is that there are animals which express PrP but which are inherently immune to prion disease. It seems that very minor changes in the PrP protein sequence are sufficient to confer apparently-complete resistance to prion infection.  Our article doesn't seem to cover this very well, but a number of species, including dogs, rabbits, and horses, are naturally protected.  Their PrP is, as far as we know, 'normally-folded', but cannot be induced to misfold into a prion form.  TenOfAllTrades(talk) 15:22, 26 August 2012 (UTC)

The prion article needs to be split into Prion and The Prion Protein
This has always been a source of confusion, and its not helping that wikipedia doesn't separate the two concepts. The Prion protein is a protein normally expressed in our brains and other tissues. It has a normal function that has yet to be fully understood (probably something involving Cu2+).

Prions are infectious proteins, of which for a long time, MISFOLDED prion protein was the only member. However they are not the same. Other proteins can be prions. Normally folded prion protein is not a prion. Case and point, there is mounting evidence that Abeta (alzheimer's) and alpha-synuclein (parkinson's) have prion like properties (ie misfolded oligomers of these proteins can be infectious). Source — Preceding unsigned comment added by 76.102.5.30 (talk) 20:17, 28 August 2012 (UTC)

Cellular vs. Common
This is incorrect; c stands for cellular. Whoever added the claim that it stands for "common" should have at least cited the origin of that claim, hence I have removed it. 2A02:8388:1601:E000:BE5F:F4FF:FECD:7CB2 (talk) 18:11, 18 November 2014 (UTC)