Hsp90

Definition

Hsp90, or heat shock protein 90, is a crucial molecular chaperone that assists in the proper folding and stabilization of proteins, particularly those involved in signal transduction and cellular stress responses. This protein plays a vital role in post-translational modifications by ensuring that newly synthesized proteins achieve their functional conformations, thereby influencing their activity, stability, and degradation pathways. Hsp90's activity is essential for maintaining cellular homeostasis, especially under stressful conditions, where it helps prevent protein aggregation and misfolding.

5 Must Know Facts For Your Next Test

1. Hsp90 is involved in the maturation of various client proteins, including steroid hormone receptors and certain kinases.
2. This chaperone is highly conserved across species, highlighting its fundamental importance in cellular processes.
3. Hsp90 functions through an ATP-dependent cycle, where ATP binding and hydrolysis drive conformational changes necessary for its activity.
4. Inhibition of Hsp90 has been studied as a potential therapeutic strategy in cancer treatment due to its role in stabilizing oncoproteins.
5. Hsp90's ability to regulate the degradation of misfolded proteins links it closely to the cellular quality control systems.

Review Questions

• How does hsp90 contribute to protein stability and function after translation?
  • Hsp90 contributes to protein stability and function by acting as a molecular chaperone that facilitates the proper folding of newly synthesized proteins. It ensures that these proteins adopt their correct three-dimensional structures, which is crucial for their activity. By preventing misfolding and aggregation, hsp90 maintains cellular protein homeostasis, allowing proteins to perform their roles effectively in various cellular processes.
• Discuss the mechanisms by which hsp90 influences post-translational modifications of client proteins.
  • Hsp90 influences post-translational modifications by interacting with client proteins during their folding process, often promoting modifications such as phosphorylation and ubiquitination. These modifications can dictate the protein's functional state, localization, and stability. Hsp90's involvement ensures that these modifications occur optimally, affecting how proteins respond to signals and stressors within the cell.
• Evaluate the potential implications of hsp90 inhibition in cancer therapy and how this relates to its role in post-translational modifications.
  • Inhibiting hsp90 has significant implications for cancer therapy as many oncogenic proteins rely on hsp90 for stabilization and proper function. By disrupting hsp90 activity, cancer cells may experience destabilization of these critical oncoproteins leading to increased degradation through mechanisms such as ubiquitination. This connection illustrates how targeting hsp90 can disrupt post-translational modifications essential for cancer cell survival and proliferation, making it a promising strategy in the development of anticancer treatments.

Related terms

Chaperone: A type of protein that assists in the proper folding and assembly of other proteins, preventing misfolding and aggregation.

Post-translational modification: The chemical modification of a protein after its translation, which can affect its function, localization, and stability.

Ubiquitination:

A process where ubiquitin molecules are attached to a protein, marking it for degradation by the proteasome.