InterPro domain: IPR001404

Molecular chaperones, or heat shock proteins (Hsps) are ubiquitous proteins that act to maintain proper protein folding within the cell [ 1 ]. They assist in the folding of nascent polypeptide chains, and are also involved in the re-folding of denatured proteins following proteotoxic stress. As their name implies, the heat shock proteins were first identified as proteins that were up-regulated under conditions of elevated temperature. However, subsequent studies have shown that increased Hsp expression is induced by a variety of cellular stresses, including oxidative stress and inflammation. Five major Hsp families have been determined, and are categorized according to their molecular size (Hsp100, Hsp90, Hsp70, Hsp60, and the small Hsps). Hsps are involved in a variety of cellular processes that are ATP-dependent. These include: prevention of protein aggregation, protein degradation, protein trafficking, and maintenance of signalling proteins in a conformation that permits activation.

Hsp90 chaperones are unique in their ability to regulate a specific subset of cellular signalling proteins that have been implicated in disease processes, including intracellular protein kinases, steroid hormone receptors, and growth factor receptors [ 2 ].

1. Microbial molecular chaperones. Adv. Microb. Physiol. 44, 93-140
2. The hsp90-based chaperone system: involvement in signal transduction from a variety of hormone and growth factor receptors. Proc. Soc. Exp. Biol. Med. 217, 420-34