Review: The HSP90 molecular chaperone-an enigmatic ATPase

Area of Science:

• Biochemistry
• Molecular Biology
• Oncology

Background:

• Heat shock protein 90 (HSP90) is a molecular chaperone essential for the stability and function of numerous client proteins.
• Key client proteins include oncogenic kinases and nuclear steroid hormone receptors, making HSP90 a significant target in cancer research.
• HSP90 function is intrinsically linked to its conformational cycle and ATPase activity, which are modulated by co-chaperones.

Purpose of the Study:

• To elucidate the precise function of HSP90's conformationally-coupled ATPase activity in its role as a molecular chaperone.
• To understand the mechanistic basis for HSP90's involvement in protein activation and stabilization.

Main Methods:

• Review of existing literature and research spanning two decades.
• Analysis of the interplay between HSP90 conformation, ATPase activity, and co-chaperone regulation.
• Consideration of in vivo studies demonstrating client protein degradation upon HSP90 inhibition.

Main Results:

• HSP90's ATPase activity is critical for its chaperone function, facilitating the conformational changes necessary for client protein maturation.
• Co-chaperones play a vital role in regulating HSP90's ATPase cycle and substrate interactions.
• Pharmacological inhibition of HSP90 ATPase leads to the degradation of oncogenic client proteins, highlighting its therapeutic potential.

Conclusions:

• The precise functional contribution of HSP90's ATPase activity to its chaperone mechanism remains an area requiring further investigation.
• Understanding this mechanism is key to developing more effective HSP90-targeted cancer therapies.
• HSP90 remains a highly promising target for anti-cancer drug development due to its role in stabilizing key oncogenic proteins.