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Nat Neurosci. 2014 Jun;17(6):822-31. doi: 10.1038/nn.3721. Epub 2014 May 18.

Inhibition of mitochondrial protein import by mutant huntingtin.

Author information

1
1] Department of Neurological Surgery, Neuroapoptosis Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. [2] Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri, USA. [3] Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA. [4] Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA.
2
Department of Neurological Surgery, Neuroapoptosis Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
3
Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
4
1] Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri, USA. [2] Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA. [3] Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA.
5
1] Department of Neurological Surgery, Neuroapoptosis Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, USA. [2] University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.

Abstract

Mitochondrial dysfunction is associated with neuronal loss in Huntington's disease (HD), a neurodegenerative disease caused by an abnormal polyglutamine expansion in huntingtin (Htt). However, the mechanisms linking mutant Htt and mitochondrial dysfunction in HD remain unknown. We identify an interaction between mutant Htt and the TIM23 mitochondrial protein import complex. Remarkably, recombinant mutant Htt directly inhibited mitochondrial protein import in vitro. Furthermore, mitochondria from brain synaptosomes of presymptomatic HD model mice and from mutant Htt-expressing primary neurons exhibited a protein import defect, suggesting that deficient protein import is an early event in HD. The mutant Htt-induced mitochondrial import defect and subsequent neuronal death were attenuated by overexpression of TIM23 complex subunits, demonstrating that deficient mitochondrial protein import causes mutant Htt-induced neuronal death. Collectively, these findings provide evidence for a direct link between mutant Htt, mitochondrial dysfunction and neuronal pathology, with implications for mitochondrial protein import-based therapies in HD.

Comment in

PMID:
24836077
PMCID:
PMC4174557
DOI:
10.1038/nn.3721
[Indexed for MEDLINE]
Free PMC Article

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