The FY56 strain was transformed with the pYES2 vector or the vector expressing GST, GST-Rsp5, or GST-Rsp5 N terminus (lanes 1–4, respectively). Extracts were made from the cells and glutathione binding proteins, as well as copurifying proteins, were isolated on glutathione-Sepharose and analyzed by SDS/PAGE and immunoblotting. GST (nonfusion protein) expression was detected separately by silver staining of the glutathione-bound fraction (data not shown).