Heat-shock protein 90 (Hsp90) is a conserved ATP-dependent chaperone with diverse cellular functions. Hsp90 is ubiquitously expressed but is further induced upon cellular stress such as heat-shock or nutrient deprivation. Hsp90 is essential for the proper folding of a diverse set of proteins called clients. These client proteins consist of important signal transduction proteins including transcription factors, kinases, and steroid hormone receptors. By regulating the final folding steps of these client proteins Hsp90 plays an important role in many cellular signaling pathways.
