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Iwata A, et al.  (2009) Intranuclear degradation of polyglutamine aggregates by the ubiquitin-proteasome system. J Biol Chem 284(15):9796-803

Abstract: Huntington disease and its related autosomal-dominant polyglutamine (pQ) neurodegenerative diseases are characterized by intraneuronal accumulation of protein aggregates. Studies on protein aggregates have revealed the importance of the ubiquitin-proteasome system as the front line of protein quality control (PQC) machinery against aberrant proteins. Recently, we have shown that the autophagy-lysosomal system is also involved in cytoplasmic aggregate degradation, but the nucleus lacked this activity. Consequently, the nucleus relies entirely on the ubiquitin-proteasome system for PQC. According to previous studies, nuclear aggregates possess a higher cellular toxicity than do their cytoplasmic counterparts, however degradation kinetics of nuclear aggregates have been poorly understood. Here we show that nuclear ubiquitin ligases San1p and UHRF-2 each enhance nuclear pQ aggregate degradation and rescued pQ-induced cytotoxicity in cultured cells and primary neurons. Moreover, UHRF-2 is associated with nuclear inclusion bodies in vitro and in vivo. Our data suggest that UHRF-2 is an essential molecule for nuclear pQ degradation as a component of nuclear PQC machinery in mammalian cells.

Status: Published

Type: Journal Article | Research Support, Non-U.S. Gov't

PubMed ID: 19218238

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Iwata A Nagashima Y Matsumoto L Suzuki T Yamanaka T Date H Deoka K Nukina N Tsuji S Papers in SGD Colleagues in SGD PubMed Google Scholar

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