In cancer, Cdc37 is phosphorylated by casein kinase 2 (CK2) and then the phosphoprotein binds to various kinase ‘clients’ and to the chaperone Hsp90. Hsp90 facilitates the folding of the clients into fully active forms to drive the cell cycle. The plant-derived quinine methid triterpenoid celastrol can inhibit the interaction between Hsp90 and Cdc37 and thereby slow cancer growth by arresting the cell cycle and inducing apoptosis. However, researchers at China Pharmaceutical University China wanted to inhibit the ‘Hsp90-Cdc37-kinase’ cycle at multiple points simultaneously for greater therapeutic effect.