Co-chaperone that binds to numerous kinases and promotes their interaction with the Hsp90 complex, resulting in stabilization and promotion of their activity. Inhibits HSP90AA1 ATPase activity. Probably forms a complex composed of chaperones HSP90 and HSP70, co-chaperones STIP1/HOP, CDC37, PPP5C, PTGES3/p23, TSC1 and client protein TSC2. Probably forms a complex composed of chaperones HSP90 and HSP70, co-chaperones CDC37, PPP5C, TSC1 and client protein TSC2, CDK4, AKT, RAF1 and NR3C1; this complex does not contain co-chaperones STIP1/HOP and PTGES3/p23. Forms a complex with Hsp90/HSP90AB1 and CDK6 (By similarity). Interacts with HSP90AA1. Interacts with AR, CDK4, CDK6 and EIF2AK1. Interacts with RB1. Interacts with KSR1. Interacts with FLCN, FNIP1 and FNIP2. Constitutively sumoylated by UBE2I. Belongs to the CDC37 family.