HSP90 and its inhibitors.

The HSP90 molecular chaperone family is highly conserved and expressed in various organisms ranging from prokaryotes to eukaryotes. HSP90 proteins play essential housekeeping functions, such as controlling the activity, turnover and trafficking of various proteins, promoting cell survival through maintaining the structural and functional integrity of some client proteins which control cell survival, proliferation and apoptosis, and play an important role in the progression of malignant disease. HSP90 proteins are ATP-dependent chaperones and the binding and hydrolysis of ATP are coupled to conformation changes of HSP90, which facilitate client protein folding and maturation. Many natural and synthetic molecular compounds have been proposed as promising cancer therapy via disrupting the formation of complex ATP-HSP90-client proteins.