Reactive oxygen species-dependent down-regulation of ubiquitin C-terminal hydrolase in Schizosaccharomyces pombe

초록

The Schizosaccharomyces pombe sdu1+ gene, belonging to the PPPDE superfamily of deubiquitinating enzyme (DUB) genes, was previously shown to encode a protein with ubiquitin C-terminal hydrolase (UCH) activity and to participate in the response against oxidative and nitrosative stresses. This work focused on the reactive oxygen species (ROS)-dependent regulation of the S. pombe sdu1+ gene. UCH activities, encoded by the sdu1+ gene, were attenuated in the S. pombe cells exposed to H<inf>2</inf>O<inf>2</inf>, superoxide radical-generating menadione (MD), and nitric oxide (NO)-generating sodium nitroprusside (SNP). Reduced glutathione (GSH) and its precursor N-acetylcysteine (NAC) were able to significantly enhance the UCH activities in the absence or presence of H<inf>2</inf>O<inf>2</inf>. However, the influences of both GSH and NAC on the ROS levels in the absence or presence of H<inf>2</inf>O<inf>2</inf> were opposite to their effects on the UCH activities under the same conditions. The UCH activities in the Sdu1-overexpressing S. pombe cells were also diminished under exposure to H<inf>2</inf>O<inf>2</inf>, MD and SNP, but still remained to be higher than those in the vector control cells. In brief, it is proposed that the S. pombe sdu1+ gene is regulated by ROS in a negative manner, the meaning of which largely remains elusive. © 2016, The Microbiological Society of Korea.

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