Phosphomimetic T5/7D-Hsp90α has the same chaperone activity on the GR as wild-type Hsp90α. Stripped GR immunopellets were incubated for 20 minutes at 30°C with Hsp70, Hop, Hsp40, and p23 in the presence of the indicated amounts of human Hsp90α (○), human Hsp90α T5/7A (■), or human Hsp90α T5/7D (▲), and steroid binding was assayed. Data are mean ± S.D. from three experiments.