1. Overexpression of p62/SQSTM1 promotes the degradations of abnormally accumulated PrP mutants in cytoplasm and relieves the associated cytotoxicities via autophagy-lysosome-dependent way.
- Author
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Xu, Yin, Zhang, Jin, Tian, Chan, Ren, Ke, Yan, Yu-E, Wang, Ke, Wang, Hui, Chen, Cao, Wang, Jing, Shi, Qi, and Dong, Xiao-Ping
- Subjects
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GENE expression , *GENETIC mutation , *CYTOPLASM , *CELL-mediated cytotoxicity , *AUTOPHAGY , *LYSOSOMES , *ADAPTOR proteins - Abstract
The protein of p62/sequestosome 1 (SQSTM1), a key cargo adaptor protein involved in autophagy-lysosome degradation, exhibits inclusion bodies structure in cytoplasm and plays a protective role in some models of neurodegenerative diseases. Some PrP mutants, such as PrP-CYTO and PrP-PG14, also form cytosolic inclusion bodies and trigger neuronal apoptosis either in cultured cells or in transgenic mice. Here, we demonstrated that the cellular p62/SQSTM1 incorporated into the inclusion bodies formed by expressing the abnormal PrP mutants, PrP-CYTO and PrP-PG14, in human embryonic kidney 293 cells. Overexpression of p62/SQSTM1 efficiently relieved the cytosolic aggregations and cell apoptosis induced by the abnormal PrPs. Autophagy-lysosome inhibitors instead of proteasome inhibitor sufficiently blocked the p62/SQSTM1-mediated degradations of abnormal PrPs. Overexpression of p62/SQSTM1 did not alter the levels of light chain 3 (LC3) in the cells expressing various PrPs. However, more complexes of p62/SQSTM1 with LC3 were detected in the cells expressing the misfolded PrPs. These data imply that p62/SQSTM1 plays an important role in the homeostasis of abnormal PrPs via autophagy-lysosome-dependent way. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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