title: Increased susceptibility of cytoplasmic over nuclear polyglutamine aggregates to autophagic degradation.
abstract: CNS neurons are endowed with the ability to recover from cytotoxic insults associated with the accumulation of proteinaceous aggregates in mouse models of polyglutamine disease, but the cellular mechanism underlying this phenomenon is unknown. Here, we show that autophagy is essential for the elimination of aggregated forms of mutant huntingtin and ataxin-1 from the cytoplasmic but not nuclear compartments. Human orthologs of yeast autophagy genes, molecular determinants of autophagic vacuole formation, are recruited to cytoplasmic but not nuclear inclusion bodies in vitro and in vivo. These data indicate that autophagy is a critical component of the cellular clearance of toxic protein aggregates and may help to explain why protein aggregates are more toxic when directed to the nucleus.
authors.affiliation: Department of Biological Sciences, BIO-X Program, Stanford University, Stanford, CA 94305-5430.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iwata
authors.forename: John C
authors.initials: JC
authors.lastname: Christianson
authors.forename: Mirella
authors.initials: M
authors.lastname: Bucci
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Ellerby
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Nukina
authors.forename: Lysia S
authors.initials: LS
authors.lastname: Forno
authors.forename: Ron R
authors.initials: RR
authors.lastname: Kopito
mesh_terms: D000067696:Ataxin-1; D000067528:Ataxins; D001343:Autophagy; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins; D020754:Spinocerebellar Ataxias; D014162:Transfection
chemical_list: C466624:ATG12 protein, human; C502778:ATG5 protein, human; C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D000067528:Ataxins; C000593750:Atxn1 protein, mouse; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; C086055:HTT protein, human; D000071058:Huntingtin Protein; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010455:Peptides; D011506:Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; C097188:polyglutamine