Identification of F-box proteins that are involved in resistance to methylmercury in Saccharomyces cerevisiae

We searched for F-box proteins that might be related to the mechanism that protects Saccharomyces cererisiae against the toxic effects of methylmercury. We found that overexpression of Hrt3 and of YIr224w rendered yeast cells resistant to methylmercury. Yeast cells that overexpressed Hrt3 and Ylr224w were barely resistant to methylmercury in the presence of a proteasome inhibitor. Our results suggest the existence of some protein(s) that enhances the toxicity of methylmercury in yeast cells and, also, that overexpression of Hrt3 or YIr224w can confer resistance to methylmercury by enhancing the polyubiquitination of this protein(s) and its degradation in proteasomes. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.