
PrionproteinistheproteinresponsibleforhumanCreutzfeldt-JakobDisease(CJD),andsomaticmutationsofthepriongeneareresponsibleforGerstmann-Straussler-ScheinkerdiseaseandFatalFamilialInsomnia.ThebovinehomologoftheprionproteinisresponsibleforbovineSpongioformEncephalopathy(BSE),alsoknownas“MadCowDisease.”Inallcases,theprionproteinhastwofoldingstates,withonestatebeingthe“normal”non-pathologicalform,andtheotherstateinducingaspongioformencephalopathy.
Normalprionproteinsproducednaturallyinthebraininteractwiththeamyloid-βpeptidesthatarehallmarksofAlzheimersdisease.Blockingthisinteractioninpreparationsmadefrommousebrainshaltedsomeneurologicaldefectscausedbytheaccumulationofamyloid-βpeptide.Itwaspreviouslythoughtthatonlyinfectiousprionproteins,ratherthantheirnormal,non-infectiouscounterparts,playedaroleinbraindegeneration(Nature,doi:10.1038/news.2009.121).
Image:PrionProteinstainingofculturedfibroblastscellstransientlytransfectedwithaplasmidcontainingtheprionproteincDNA.