FIG. 4.

Sti1 mutations that suppress Hsp104-mediated curing affect interaction with Hsp90. Cells lacking chromosomal STI1 and carrying empty vector (cont) or plasmids expressing His₆-tagged Sti1, Sti1(C49Y), Sti1(G325D), or Sti1(T526I) were grown as indicated in Materials and Methods. Sti1-containing complexes were purified from lysates by using metal affinity chromatography. Complexes were separated by SDS-PAGE, blotted, and probed with antibodies specific to Sti1 (top panel), an antibody raised against the C terminus of yeast Hsp90 that reacts with both Hsc82 and Hsp82 (Hsc82 + Hsp82) and a commercially available antibody raised against human Hsp90α that recognizes yeast Hsp82 only (Hsp82). The bottom panel (CB) shows a portion of a Coomassie brilliant blue-stained gel of the purified complexes, with molecular size markers indicated. Identical volumes of samples were loaded in this gel and in the gels used for the blots. The arrowhead indicates the position of Sti1.