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'''Hsp90''' (Heat Shock Protein 90) is a [[chaperone protein]] that assists other proteins to fold properly, stabilizes proteins against heat stress, and aids in protein degradation. It also stabilizes a number of proteins required for tumor growth, which is why Hsp90 inhibitors are being studied as a treatment for cancer.
{{Short description|An overview of the Hsp90 protein family and its biological significance}}


== Structure ==
==Overview==
Hsp90 is a flexible and dynamic protein. It is composed of three different domains: the N-terminal domain, the middle domain, and the C-terminal domain. The N-terminal domain has ATP binding properties, the middle domain is necessary for client protein and co-chaperone binding, and the C-terminal domain involves dimerization.
[[File:Hsp90_structure.png|thumb|right|300px|Structure of the Hsp90 protein.]]
Hsp90, or Heat Shock Protein 90, is a highly conserved molecular chaperone that plays a critical role in the folding, stability, and function of many proteins, particularly those involved in signal transduction, cell cycle control, and protein degradation. It is a member of the heat shock protein family, which is upregulated in response to stress conditions such as elevated temperatures, oxidative stress, and exposure to toxins.


== Function ==
==Structure and Function==
Hsp90 is a molecular chaperone that plays a key role in the conformational maturation of oncogenic signaling proteins, including kinases and transcription factors. It is also involved in protein degradation and is necessary for the proper functioning of the [[proteasome]], a major protein degradation pathway in the cell.
Hsp90 is a dimeric protein, meaning it consists of two identical subunits. Each subunit is composed of three domains: the N-terminal domain, which binds ATP; the middle domain, which is involved in client protein binding; and the C-terminal domain, which is responsible for dimerization and also contains a second ATP-binding site.


== Clinical significance ==
The ATPase activity of Hsp90 is crucial for its function. The binding and hydrolysis of ATP induce conformational changes that are essential for the chaperone cycle, allowing Hsp90 to interact with a wide range of client proteins. These client proteins include kinases, transcription factors, and other signaling molecules, many of which are involved in cancer progression, making Hsp90 a target for cancer therapeutics.
Hsp90 is often overexpressed in cancer cells, and its inhibition can affect multiple signaling pathways simultaneously. This makes it a promising target for new anti-cancer drugs. Several Hsp90 inhibitors are currently being tested in clinical trials.


== See also ==
==Biological Significance==
[[File:Hsp90_client_proteins.png|thumb|left|300px|Hsp90 interacts with various client proteins.]]
Hsp90 is involved in the maturation and stabilization of a variety of "client" proteins, many of which are key regulators of cellular homeostasis. It is particularly important in the context of cancer, as many oncogenic proteins are dependent on Hsp90 for their stability and function. Inhibition of Hsp90 can lead to the degradation of these client proteins, thereby suppressing tumor growth.
 
In addition to its role in cancer, Hsp90 is also implicated in neurodegenerative diseases, where it helps in the refolding of misfolded proteins and prevents the aggregation of proteins such as tau and alpha-synuclein.
 
==Hsp90 Inhibitors==
Given its role in stabilizing oncogenic proteins, Hsp90 has become a target for cancer drug development. Several Hsp90 inhibitors, such as geldanamycin and its derivatives, have been developed and are currently being tested in clinical trials. These inhibitors bind to the ATP-binding site of Hsp90, preventing its chaperone activity and leading to the degradation of client proteins.
 
==Related Proteins==
Hsp90 is part of a larger family of heat shock proteins, which includes Hsp70, Hsp60, and small heat shock proteins. Each of these proteins has distinct functions but often work together to maintain protein homeostasis within the cell.
 
==Related pages==
* [[Heat shock protein]]
* [[Heat shock protein]]
* [[Chaperone (protein)]]
* [[Molecular chaperone]]
* [[Proteasome]]
* [[Protein folding]]
* [[Cancer]]
* [[Cancer therapy]]


[[Category:Molecular biology]]
[[Category:Proteins]]
[[Category:Proteins]]
[[Category:Chaperone proteins]]
[[Category:Chaperone proteins]]
[[Category:Cancer research]]
{{protein-stub}}
{{medicine-stub}}
<gallery>
File:Hsp90_schematic_2cg9.png|Hsp90 schematic
File:Hsp90_ATP_pocket.jpg|Hsp90 ATP pocket
File:Hsp_90_pincer_movement.png|Hsp90 pincer movement
File:hsp90cycle.jpg|Hsp90 cycle
File:hsp90_5.jpg|Hsp90
File:hsp903=4.jpg|Hsp90
File:gr_hsp90_translocation.png|GR Hsp90 translocation
File:Hsp90_cycle_SHR.jpg|Hsp90 cycle SHR
</gallery>

Revision as of 17:32, 18 February 2025

An overview of the Hsp90 protein family and its biological significance


Overview

File:Hsp90 structure.png
Structure of the Hsp90 protein.

Hsp90, or Heat Shock Protein 90, is a highly conserved molecular chaperone that plays a critical role in the folding, stability, and function of many proteins, particularly those involved in signal transduction, cell cycle control, and protein degradation. It is a member of the heat shock protein family, which is upregulated in response to stress conditions such as elevated temperatures, oxidative stress, and exposure to toxins.

Structure and Function

Hsp90 is a dimeric protein, meaning it consists of two identical subunits. Each subunit is composed of three domains: the N-terminal domain, which binds ATP; the middle domain, which is involved in client protein binding; and the C-terminal domain, which is responsible for dimerization and also contains a second ATP-binding site.

The ATPase activity of Hsp90 is crucial for its function. The binding and hydrolysis of ATP induce conformational changes that are essential for the chaperone cycle, allowing Hsp90 to interact with a wide range of client proteins. These client proteins include kinases, transcription factors, and other signaling molecules, many of which are involved in cancer progression, making Hsp90 a target for cancer therapeutics.

Biological Significance

File:Hsp90 client proteins.png
Hsp90 interacts with various client proteins.

Hsp90 is involved in the maturation and stabilization of a variety of "client" proteins, many of which are key regulators of cellular homeostasis. It is particularly important in the context of cancer, as many oncogenic proteins are dependent on Hsp90 for their stability and function. Inhibition of Hsp90 can lead to the degradation of these client proteins, thereby suppressing tumor growth.

In addition to its role in cancer, Hsp90 is also implicated in neurodegenerative diseases, where it helps in the refolding of misfolded proteins and prevents the aggregation of proteins such as tau and alpha-synuclein.

Hsp90 Inhibitors

Given its role in stabilizing oncogenic proteins, Hsp90 has become a target for cancer drug development. Several Hsp90 inhibitors, such as geldanamycin and its derivatives, have been developed and are currently being tested in clinical trials. These inhibitors bind to the ATP-binding site of Hsp90, preventing its chaperone activity and leading to the degradation of client proteins.

Related Proteins

Hsp90 is part of a larger family of heat shock proteins, which includes Hsp70, Hsp60, and small heat shock proteins. Each of these proteins has distinct functions but often work together to maintain protein homeostasis within the cell.

Related pages