Disease-associated mutations of TDP-43 promote turnover of the protein through the proteasomal pathway
Autor: | Hideaki Kume, Hirohiko Hohjoh, Wataru Araki, Yumiko M. Araki, Kazumi Motoki, Akira Tamaoka, Seiji Minegishi |
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Rok vydání: | 2014 |
Předmět: |
Proteasome Endopeptidase Complex
Neuroscience (miscellaneous) Cycloheximide Biology medicine.disease_cause Cellular and Molecular Neuroscience chemistry.chemical_compound Epoxomicin Mutant protein Cell Line Tumor mental disorders medicine Humans Phosphorylation Inclusion Bodies Mutation Neurodegeneration Amyotrophic Lateral Sclerosis Protein turnover nutritional and metabolic diseases Brain medicine.disease nervous system diseases Cell biology DNA-Binding Proteins Neurology chemistry Biochemistry Proteasome Proteasome inhibitor Frontotemporal Lobar Degeneration medicine.drug |
Zdroj: | Molecular neurobiology. 50(3) |
ISSN: | 1559-1182 |
Popis: | TAR DNA-binding protein (TDP-43) is a major component of most ubiquitin-positive neuronal and glial inclusions of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). A number of missense mutations in the TARDBP gene have been identified in patients with familial and sporadic ALS, as well as familial FTLD with ALS. In the diseased states, TDP-43 proteins exhibit characteristic alterations, including truncation, abnormal phosphorylation, and altered subcellular distribution. However, the mechanisms by which TDP-43 mutations induce neurodegeneration remain unclear at present. In the current study, we analyzed protein turnover and subcellular distribution of wild-type TDP-43 and two disease-associated mutants (G298S and A382T) in human neuroblastoma SH-SY5Y cells stably expressing TDP-43 with a C-terminal tag. Cycloheximide chase experiments revealed more rapid turnover of TDP-43 mutant proteins than their wild-type counterpart. The decrease in the TDP-43 level after cycloheximide treatment was partially recovered upon co-treatment with the proteasome inhibitor, epoxomicin, but not the lysosomotropic agent, chloroquine, suggesting involvement of the proteasomal pathway in TDP-43 degradation. Analysis of the subcellular distribution of TDP-43 revealed predominant localization in the nuclear fraction, whereas the relative level in the cytoplasm remained unaltered in cells expressing either mutant protein, compared with wild-type protein. Our results suggest that higher turnover of disease-associated mutant TDP-43 proteins through the ubiquitin proteasome system is pathogenetically relevant and highlight the significance of proteolysis in the pathogenetic mechanism of TDP-43 proteinopathy. |
Databáze: | OpenAIRE |
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