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Ubiquitin‐proteasome system is responsible for the protection of yeast and human cells against methylmercury
Author(s) -
Hwang GiWook,
Furuchi Takemitsu,
Naganuma Akira
Publication year - 2002
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.01-0899fje
Subject(s) - ubiquitin , proteasome , saccharomyces cerevisiae , yeast , proteolysis , chemistry , ubiquitin conjugating enzyme , deubiquitinating enzyme , biochemistry , microbiology and biotechnology , biology , gene , enzyme , ubiquitin ligase
The mechanism responsible for the toxic effects of methylmercury (MeHg), an important environmental pollutant, is poorly understood. We have identified a gene, CDC34 , that confers resistance to MeHg in Saccharomyces cerevisiae by screening a yeast genomic DNA library. CDC34 encodes a ubiquitin‐conjugating enzyme, Cdc34, which is involved in ubiquitin‐dependent proteolysis. Overexpression of Cdc34 results in significant resistance to MeHg both in yeast and human cells, and it increases the cellular level of ubiquitinated proteins. The ubiquitinconjugating activity of Cdc34 is essential for the Cdc34‐mediated resistance to MeHg, and the protective effect of the overexpression of Cdc34 is depressed by inhibition of proteasome activity. Our results support the hypothesis that MeHg induces the cellular accumulation of a certain protein(s) that causes cell damage and that this protein(s) is degraded after its ubiquitination in proteasomes.