Details

Autor(en) / Beteiligte

• Zucchelli, Silvia
• Marcuzzi, Federica
• Codrich, Marta
• Agostoni, Elena
• Vilotti, Sandra
• Biagioli, Marta
• Pinto, Milena
• Carnemolla, Alisia
• Santoro, Claudio
• Gustincich, Stefano
• Persichetti, Francesca

Titel

Tumor Necrosis Factor Receptor-associated Factor 6 (TRAF6) Associates with Huntingtin Protein and Promotes Its Atypical Ubiquitination to Enhance Aggregate Formation

Ist Teil von

• The Journal of biological chemistry, 2011-07, Vol.286 (28), p.25108-25117

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2011

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Huntington disease (HD) is a neurodegenerative disorder caused by an expansion of polyglutamines in the first exon of huntingtin (HTT), which confers aggregation-promoting properties to amino-terminal fragments of the protein (N-HTT). Mutant N-HTT aggregates are enriched for ubiquitin and contain ubiquitin E3 ligases, thus suggesting a role for ubiquitination in aggregate formation. Here, we report that tumor necrosis factor receptor-associated factor 6 (TRAF6) binds to WT and polyQ-expanded N-HTT in vitro as well as to endogenous full-length proteins in mouse and human brain in vivo. Endogenous TRAF6 is recruited to cellular inclusions formed by mutant N-HTT. Transient overexpression of TRAF6 promotes WT and mutant N-HTT atypical ubiquitination with Lys6, Lys27, and Lys29 linkage formation. Both interaction and ubiquitination seem to be independent from polyQ length. In cultured cells, TRAF6 enhances mutant N-HTT aggregate formation, whereas it has no effect on WT N-HTT protein localization. Mutant N-HTT inclusions are enriched for ubiquitin staining only when TRAF6 and Lys6, Lys27, and Lys29 ubiquitin mutants are expressed. Finally, we show that TRAF6 is up-regulated in post-mortem brains from HD patients where it is found in the insoluble fraction. These results suggest that TRAF6 atypical ubiquitination warrants investigation in HD pathogenesis.