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Interaction of huntingtin fragments with brain membranes - clues to early dysfunction in Huntington's disease

Item Type:Article
Title:Interaction of huntingtin fragments with brain membranes - clues to early dysfunction in Huntington's disease
Creators Name:Suopanki, J., Goetz, C., Lutsch, G., Schiller, J., Harjes, P., Herrmann, A. and Wanker, E.E.
Abstract:Huntingtin is a large, multi-domain protein of unknown function in the brain. An abnormally elongated polyglutamine stretch in its N-terminus causes Huntington's disease (HD), a progressive neurodegenerative disorder. Huntingtin has been proposed to play a functional role in membrane trafficking via proteins involved in endo- and exocytosis. Here, we supply evidence for a direct association between huntingtin and membranes. In the brains of R6/2 mice with HD pathology, a 64 kDa N-terminal huntingtin fragment accumulated in postsynaptic membranes during the pre-symptomatic period of 4-8 weeks of age. In addition, an oligomeric fragment of approximately 200 kDa was detected at 8 weeks of age. Simultaneous progressive changes in distribution of amphiphysin, synaptojanin, and subunits of NMDA- and AMPA-receptors provide a strong indication of dysfunctional synaptic trafficking. Composition of the major phospholipids in the synaptic membranes was unaffected. In vitro, large unilamellar vesicles of brain lipids readily associated with soluble N-terminal huntingtin exon 1 fragments and stimulated fibrillogenesis of mutant huntingtin aggregates. Moreover, interaction of both mutant and wild-type huntingtin exon 1 fragments with brain lipids caused bilayer perturbation, mediated through a proline-rich region adjacent to the polyglutamines. This suggests that lipid interactions in vivo could influence misfolding of huntingtin and may play an early role in HD pathogenesis.
Keywords:Fibrillogenesis, Huntingtin, Oligomers, Postsynaptic Membranes
Source:Journal of Neurochemistry
Publisher:Blackwell Publishing
Page Range:870-884
Date:February 2006
Official Publication:https://doi.org/10.1111/j.1471-4159.2005.03620.x
PubMed:View item in PubMed

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