Co-chaperone that binds to numerous kinases and promotes their interaction with the Hsp90 complex, resulting in stabilization and promotion of their activity. Involved in both the HOG and the PKC MAP kinase signaling cascade necessary for adaptation to stress conditions due to high osmolarity or cell wall perturbation. Forms a complex with Hsp90. Interacts with CDC28, CAK1 HOG1, SLT2 and STE11. Phosphorylation at Ser-14 is required for the interactions with HOG1 and SLT2 MAP kinases and is crucial for adaptation to stress conditions due to high osmolarity or cell wall perturbation. Present with 10200 molecules/cell in log phase SD medium. Belongs to the CDC37 family.