Editing Prion (section)

=== Degradation by living beings ===
More recent studies suggest scrapie prions can be degraded by diverse cellular machinery of the affected animal cell. In an infected cell, extracellular lysosomal PrP<sup>Sc</sup> does not tend to accumulate and is rapidly cleared by the [[lysosome]] via the [[endosome]]. The intracellular portion is harder to clear and tends to build up. The [[Proteasome|ubiquitin proteasome system]] appears to be able to degrade small enough aggregates. [[Autophagy]] plays a bigger role by accepting PrP<sup>Sc</sup> from the ER lumen and degrading it. Altogether these mechanisms allow the cell to delay its death from being overwhelmed by misfolded proteins.<ref name=":1" /> Inhibition of autophagy accelerates prion accumulation whereas encouragement of autophagy promotes prion clearance. Some autophagy-promoting compounds have shown promise in animal models by delaying disease onset and death.<ref name=":1">{{cite journal | vauthors = López-Pérez Ó, Badiola JJ, Bolea R, Ferrer I, Llorens F, Martín-Burriel I | title = An Update on Autophagy in Prion Diseases | language = English | journal = Frontiers in Bioengineering and Biotechnology | volume = 8 | pages = 975 | date = 2020-08-27 | pmid = 32984276 | pmc = 7481332 | doi = 10.3389/fbioe.2020.00975 | doi-access = free }}</ref>

In addition, [[keratinase]] from [[Bacillus licheniformis|''B. licheniformis'']],<ref>{{cite journal | vauthors = Langeveld JP, Wang JJ, Van de Wiel DF, Shih GC, Garssen GJ, Bossers A, Shih JC | title = Enzymatic degradation of prion protein in brain stem from infected cattle and sheep | journal = The Journal of Infectious Diseases | volume = 188 | issue = 11 | pages = 1782–9 | date = December 2003 | pmid = 14639552 | doi = 10.1086/379664 }}</ref><ref>{{cite journal | vauthors = Okoroma EA, Purchase D, Garelick H, Morris R, Neale MH, Windl O, Abiola OO | title = Enzymatic formulation capable of degrading scrapie prion under mild digestion conditions | journal = PLOS ONE | volume = 8 | issue = 7 | pages = e68099 | date = 2013-07-16 | pmid = 23874511 | pmc = 3712960 | doi = 10.1371/journal.pone.0068099 | doi-access = free | bibcode = 2013PLoSO...868099O }}</ref> alkaline [[serine protease]] from ''Streptomyces sp'',<ref>{{cite journal | vauthors = Hui Z, Doi H, Kanouchi H, Matsuura Y, Mohri S, Nonomura Y, Oka T | title = Alkaline serine protease produced by Streptomyces sp. degrades PrP(Sc) | journal = Biochemical and Biophysical Research Communications | volume = 321 | issue = 1 | pages = 45–50 | date = August 2004 | pmid = 15358213 | doi = 10.1016/j.bbrc.2004.06.100 }}</ref> [[subtilisin]]-like pernisine from ''[[Aeropyrum pernix]]'',<ref>{{cite journal | vauthors = Snajder M, Vilfan T, Cernilec M, Rupreht R, Popović M, Juntes P, Serbec VČ, Ulrih NP | title = Enzymatic degradation of PrPSc by a protease secreted from Aeropyrum pernix K1 | journal = PLOS ONE | volume = 7 | issue = 6 | pages = e39548 | date = 2012 | pmid = 22761822 | pmc = 3386259 | doi = 10.1371/journal.pone.0039548 | doi-access = free | bibcode = 2012PLoSO...739548S }}</ref> alkaline protease from ''[[Nocardiopsis]] sp'',<ref>{{cite journal | vauthors = Mitsuiki S, Hui Z, Matsumoto D, Sakai M, Moriyama Y, Furukawa K, Kanouchi H, Oka T | title = Degradation of PrP(Sc) by keratinolytic protease from Nocardiopsis sp. TOA-1 | journal = Bioscience, Biotechnology, and Biochemistry | volume = 70 | issue = 5 | pages = 1246–8 | date = May 2006 | pmid = 16717429 | doi = 10.1271/bbb.70.1246 }}</ref> [[nattokinase]] from ''[[Bacillus subtilis|B. subtilis]]'',<ref>{{cite journal | vauthors = Hsu RL, Lee KT, Wang JH, Lee LY, Chen RP | title = Amyloid-degrading ability of nattokinase from Bacillus subtilis natto | journal = Journal of Agricultural and Food Chemistry | volume = 57 | issue = 2 | pages = 503–8 | date = January 2009 | pmid = 19117402 | doi = 10.1021/jf803072r | bibcode = 2009JAFC...57..503H }}</ref> engineered subtilisins from ''B. lentus''<ref>{{Cite journal | vauthors = Booth CJ, Johnson CJ, Pedersen JA |date= April 2013 |title=Microbial and enzymatic inactivation of prions in soil environments |url=https://linkinghub.elsevier.com/retrieve/pii/S0038071713000035 |journal=Soil Biology and Biochemistry |volume=59 |pages=1–15 |doi=10.1016/j.soilbio.2012.12.016 |bibcode=2013SBiBi..59....1B |issn=0038-0717}}</ref><ref>{{cite journal | vauthors = Dickinson J, Murdoch H, Dennis MJ, Hall GA, Bott R, Crabb WD, Penet C, Sutton JM, Raven ND | title = Decontamination of prion protein (BSE301V) using a genetically engineered protease | journal = The Journal of Hospital Infection | volume = 72 | issue = 1 | pages = 65–70 | date = May 2009 | pmid = 19201054 | doi = 10.1016/j.jhin.2008.12.007 }}</ref> and serine protease from three lichen species<ref>{{cite journal | vauthors = Johnson CJ, Bennett JP, Biro SM, Duque-Velasquez JC, Rodriguez CM, Bessen RA, Rocke TE | title = Degradation of the disease-associated prion protein by a serine protease from lichens | journal = PLOS ONE | volume = 6 | issue = 5 | pages = e19836 | date = May 2011 | pmid = 21589935 | pmc = 3092769 | doi = 10.1371/journal.pone.0019836 | doi-access = free | bibcode = 2011PLoSO...619836J }}</ref> have been found to degrade PrP<sup>Sc</sup>.