GST-Ipl1p (pSB196; Sue Biggins, Fred Hutchinson Cancer Research Center) and GST-Sli15p (residues 554–698, pSB503; Sue Biggins) were purified as previously described (Gestaut et al., 2008 (link); Kim et al., 2017 (link); Tien et al., 2010 (link); Zelter et al., 2015 (link)). Briefly, GST-Sli15p and GST-Ipl1p were expressed at 37°C and 23°C, respectively, for 2 h. GST-Ipl1p was purified using GSTrap HP (GE Healthcare Biosciences) following the manufacturer’s instructions, except that the elution buffer was 50 mM Tris buffer (pH 8.0) containing 250 mM KCl and 10 mM glutathione. A HiTrap 26/10 desalting column (GE Healthcare) was used to exchange the buffer to 50 mM HEPES buffer (pH 7.4) containing 100 mM NaCl. GST-Sli15p was purified with glutathione-Sepharose 4B resin (GE Healthcare) following the manufacturer’s instructions. Elution buffer was 20 mM Tris buffer (pH 8.0) containing 200 mM NaCl, 1 mM β-mercaptoethanol, 1 mM EDTA, and 10 mM glutathione.