A review of process on the Heat Shock Protein 90 (Hsp90) structural specificity and functional diversity

Heat Shock Protein 90 (Hsp90) is a molecular chaperone which plays an active role in maintaining protein homeostasis. Hsp90 is known to be highly expressed in tumour cells where it regulates stability and function of several key oncogenic client proteins including Akt kinase, EGFR, CDK and PDGFR. These client proteins are mutated or overexpressed in tumours and are involved in tumour progression and metastasis due to their roles in signaling pathways, cell cycle and apoptosis. Hsp90 has two isoforms, namely Hsp90α and Hsp90β and share 85% sequence homology. Hsp90β is the constitutive isoform, however, Hsp90α is highly induced in many cancers and is responsible for tumorigenesis.