A critical role for CHIP in the aggresome pathway.
Recent evidence suggests that aggresome formation is a physiologic stress response not limited to misfolded proteins. That stress response, termed "physiologic aggresome," is exemplified by aggresome formation of inducible nitric oxide synthase (iNOS), an important host defense protein. CHIP (carboxy terminus of Hsp70-interacting protein) is a highly conserved protein that ... has been shown to mediate substrate ubiquitination and degradation by the proteasome. In this study, we show that CHIP has a previously unexpected critical role in the aggresome pathway. CHIP interacts with iNOS and promotes its ubiquitination and degradation by the proteasome as well as its sequestration to the aggresome. CHIP-mediated iNOS targeting to the proteasome sequentially precedes CHIP-mediated iNOS sequestration to the aggresome. CHIP is required for iNOS preaggresome structures to form a mature aggresome. Furthermore, CHIP is required for targeting the mutant form of cystic fibrosis transconductance regulator (CFTRDeltaF508) to the aggresome. Importantly, the ubiquitin ligase function of CHIP is required in targeting preaggresomal structures to the aggresome by promoting an iNOS interaction with histone deacetylase 6, which serves as an adaptor between ubiquitinated proteins and the dynein motor. This study reveals a critical role for CHIP in the aggresome pathway.
Mesh Terms:
Cell Line, Cystic Fibrosis Transmembrane Conductance Regulator, Cytosol, Detergents, Dyneins, Gene Knockdown Techniques, Histone Deacetylases, Humans, Inclusion Bodies, Microtubules, Nitric Oxide Synthase Type II, Phenotype, Proteasome Endopeptidase Complex, Protein Binding, Protein Processing, Post-Translational, Protein Structure, Tertiary, Protein Transport, Ubiquitin-Protein Ligases, Ubiquitination
Cell Line, Cystic Fibrosis Transmembrane Conductance Regulator, Cytosol, Detergents, Dyneins, Gene Knockdown Techniques, Histone Deacetylases, Humans, Inclusion Bodies, Microtubules, Nitric Oxide Synthase Type II, Phenotype, Proteasome Endopeptidase Complex, Protein Binding, Protein Processing, Post-Translational, Protein Structure, Tertiary, Protein Transport, Ubiquitin-Protein Ligases, Ubiquitination
Mol. Cell. Biol.
Date: Jan. 01, 2009
PubMed ID: 18955503
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