What is the Origin of Heat Shock Protein 90?

Hsp90 belongs to the family of heat shock proteins, which were initially identified due to their dramatically increased expression in cells exposed to thermal or other environmental stressors. The name reflects their role in protecting cellular proteins from denaturation under stress conditions. Its evolutionary conservation across species underscores its fundamental importance to cell survival and proteostasis, the maintenance of the cellular protein network.

What is the Mechanism of Heat Shock Protein 90?

The chaperone operates through a complex, ATP-dependent cycle, working in partnership with various co-chaperone proteins. For hormonal health, its critical mechanism involves binding to and stabilizing unliganded steroid hormone receptors, such as the glucocorticoid and androgen receptors, keeping them in a conformationally receptive state. This stabilization is necessary to maintain the receptor's high affinity for its cognate hormone ligand. Upon hormone binding, Hsp90 dissociates, allowing the now-activated receptor to translocate to the nucleus and initiate gene transcription.

Heat Shock Protein 90

Meaning

Heat Shock Protein 90 (Hsp90) is a highly abundant, essential molecular chaperone protein found within the cells of all living organisms. Its core function is to assist in the proper folding, stability, and functional maturation of a select group of crucial cellular proteins, known as client proteins. Hsp90 acts as a quality control mechanism, preventing misfolding and aggregation, which is particularly important for the stability of key signaling molecules. Dysfunction of Hsp90 is implicated in various diseases, including cancer and neurodegeneration.