Related Experiment Videos
Extended polyglutamine selectively interacts with caspase-8 and -10 in nuclear aggregates
1Department of Genetics, National Children's Medical Research Center, 3-35-31, Taishido, Setagaya, Tokyo 154-8509, Japan.
Cell Death and Differentiation
|September 11, 2001
Summary
Extended polyglutamine in neurodegenerative diseases activates caspase-8 and -10. This aggregate-induced autoactivation reveals a novel toxic gain-of-function mechanism in CAG-repeat disorders.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Inherited neurodegenerative disorders like Huntington's disease are linked to expanded CAG/polyglutamine repeats.
- The precise molecular mechanisms driving these conditions remain unclear.
Purpose of the Study:
- To investigate the role and selectivity of caspases in polyglutamine-mediated pathogenesis.
- To elucidate the mechanism of caspase activation in the context of expanded polyglutamine.
Main Methods:
- Analysis of caspase activation and recruitment to nuclear polyglutamine aggregates.
- Co-immunoprecipitation assays to determine caspase-polyglutamine interactions.
- Functional studies using dominant-negative caspase-8 to assess its role in polyglutamine-induced apoptosis.
Main Results:
- Caspase-8 and its homolog caspase-10 were proteolytically activated and recruited to nuclear polyglutamine aggregates.
- Caspase-8 and -10, but not other caspases, co-immunoprecipitated with pathologically extended polyglutamine.
- Inhibition of caspase-8 activity blocked polyglutamine-mediated nuclear apoptotic phenotypes.
Conclusions:
- Caspase-8 and -10 autoactivate due to proximity within polyglutamine aggregates.
- This represents a novel toxic gain-of-function mechanism contributing to CAG-repeat disorder pathogenesis.