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SUMO-1 modification on K166 of polyQ-expanded ataxin-3 strengthens its stability and increases its cytotoxicity.

ABSTRACT: Post-translational modification by SUMO was proposed to modulate the pathogenesis of several neurodegenerative diseases. Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is an autosomal dominant neurodegenerative disease caused by polyQ-expanded ataxin-3. We have previously shown that ataxin-3 was a new target of SUMOylation in vitro and in vivo. Here we identified that the major SUMO-1 binding site was located on lysine 166. SUMOylation did not influence the subcellular localization, ubiquitination or aggregates formation of mutant-type ataxin-3, but partially increased its stability and the cell apoptosis. Our findings revealed the role of ataxin-3 SUMOylation in SCA3/MJD pathogenesis.

SUBMITTER: Zhou YF

PROVIDER: S-EPMC3561348 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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SUMO-1 modification on K166 of polyQ-expanded ataxin-3 strengthens its stability and increases its cytotoxicity.

Zhou Ya-Fang YF Liao Shu-Sheng SS Luo Ying-Ying YY Tang Jian-Guang JG Wang Jun-Ling JL Lei Li-Fang LF Chi Jing-Wei JW Du Juan J Jiang Hong H Xia Kun K Tang Bei-Sha BS Shen Lu L

PloS one 20130131 1

Post-translational modification by SUMO was proposed to modulate the pathogenesis of several neurodegenerative diseases. Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is an autosomal dominant neurodegenerative disease caused by polyQ-expanded ataxin-3. We have previously shown that ataxin-3 was a new target of SUMOylation in vitro and in vivo. Here we identified that the major SUMO-1 binding site was located on lysine 166. SUMOylation did not influence the subcellular localizat ...[more]

PMID: 23382880

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Project description:Spinocerebellar ataxia type-1 is caused by an abnormally expanded polyglutamine (polyQ) tract in ataxin-1 protein. These expansions are responsible for protein misfolding and self-assembly into intranuclear inclusion bodies (IIBs) that are linked to neuronal death. Here, we describe a nuclear protein aggregation model of pathogenic human ataxin-1. Using an inducible Sleeping Beauty transposon system, we overexpressed ATXN1Q82 gene in human mesenchymal stem cells that are resistant to the early cytotoxic effects of the mutant protein. We characterized the structure and the protein composition of insoluble polyQ IIBs which gradually occupy the nuclei. In response to their formation, our transcriptome analysis reveals a cerebellum-specific perturbed protein interaction network, primarily affecting protein translation. Our study resolves the previously unknown architecture of insoluble polyQ IIBs and suggests that they affect the assembly and the function of the ribosome. Our inducible cell system faithfully models a human cerebellum at the end-stage of the disease.

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