HSP90AA1 Protein

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HSP90AA1 Protein

Introduction

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">HSP90AA1 Protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>HSP90AA1</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>HSP90AA1</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=HSP90AA1" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</a>, <a href="/wiki/alzheimer's-disease" style="color:#ef9a9a">ALZHEIMER'S DISEASE</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a></td>
</tr>
<tr>
<td class="label">SciDEX Hypotheses</td>
<td><a href="/hypothesis/h-0f00fd75" style="color:#ce93d8" title="Score: 0.53">HSP90-Tau Disaggregation Complex Enhance...</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">497 edges</a></td>
</tr>
</table>

Hsp90Aa1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

...

HSP90AA1 Protein

Introduction

Hsp90Aa1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

--- [@hsp2022]
title: HSP90AA1 Protein (Heat shock protein HSP 90-alpha) [@targeting2023]
category: protein [@hspaa2022]

Overview [@hsp2023]

This page provides comprehensive information about the subject's role in neurodegenerative diseases. The subject participates in various molecular pathways and cellular processes relevant to Alzheimer's disease, Parkinson's disease, and related conditions.

Basic Information

Protein Name: Heat shock protein HSP 90-alpha Gene: HSP90AA1 UniProt ID: P07900 PDB Structures: 2IOJ, 2V7X, 3Q6P Molecular Weight: ~90 kDa Subcellular Localization: Cytoplasm, Nucleus

Structure

HSP90AA1 is a dimeric molecular chaperone with a unique architecture:

N-terminal Domain (1-220 aa): ATP binding pocket (17 Å pocket), the "lid" segment undergoes conformational changes during the ATPase cycle
Middle Domain (230-600 aa): Client protein binding site, contains a highly conserved catalytic loop involved in ATP hydrolysis
C-terminal Domain (600-705 aa): Dimerization domain with EEVD motif for co-chaperone binding

The dimerization creates a molecular "clamp" that can capture and fold client proteins through an ATP-dependent conformational cycle.

Normal Function

Protein Folding and Quality Control

HSP90AA1 is one of the most abundant cytosolic chaperones, constituting 1-2% of total cellular protein. It functions as a specialized folding machine:

Folding of metastable proteins: HSP90AA1 stabilizes partially folded proteins that would otherwise aggregate
Mutant protein stabilization: Many disease-causing mutant proteins require HSP90AA1 for stability (e.g., mutant p53, mutant kinases)
Quality control: Selectively recognizes proteins with exposed hydrophobic patches

Client Protein Network

HSP90AA1 regulates over 400 known client proteins, including:

Kinases: LRRK2, RIPK1, RIPK3, AKT, RAF, EGFR
Transcription factors: [NF-κB](/entities/nf-kb), HIF-1α, p53, STAT3
E3 ligases: CHIP (STUB1), parkin
Signal transduction proteins: IRAK1, IKK complex

ATPase Cycle

The HSP90AA1 chaperone cycle consists of:

Open state: ADP/ATP-free, client protein binds

Closed state: ATP binding triggers conformational change, client is trapped

Hydrolysis: ATP hydrolysis to ADP, conformational strain applied to client

Release: ADP release, client folds or is released for another cycle

Role in Neurodegeneration

Alzheimer's Disease

HSP90AA1 plays complex roles in AD pathogenesis:

[Tau](/proteins/tau) metabolism: HSP90AA1 co-localizes with neurofibrillary tangles and can regulate tau phosphorylation through client proteins like [GSK-3β](/entities/gsk3-beta) and [CDK5](/proteins/cdk5)
Amyloid processing: Modulates [γ-secretase](/entities/gamma-secretase) activity through direct interaction, affecting [Aβ](/proteins/amyloid-beta) production
Synaptic protection: Protects synaptic proteins from oxidative damage
Neuroinflammation: Regulates NF-κB signaling in [microglia](/cell-types/microglia-neuroinflammation) through IKK complex client relationship

Parkinson's Disease

In PD, HSP90AA1 has dual roles:

LRRK2 regulation: HSP90AA1 is the primary chaperone for mutant LRRK2 (G2019S), stabilizing the kinase and facilitating its proper folding. Inhibiting HSP90AA1 promotes LRRK2 degradation
[α-synuclein](/proteins/alpha-synuclein) aggregation: Modulates α-synuclein oligomerization through network partners
Mitochondrial quality control: Regulates PINK1/parkin mitophagy pathway through client protein interactions

Amyotrophic Lateral Sclerosis (ALS)

HSP90AA1 involvement in ALS:

[TDP-43](/mechanisms/tdp-43-proteinopathy) metabolism: HSP90AA1 regulates TDP-43 solubility and aggregation
Stress granule dynamics: Modulates stress granule formation and disassembly
[C9orf72](/entities/c9orf72) dipeptide repeats: Network analysis suggests HSP90AA1 involvement in DPR toxicity
SOD1 folding: Assists in proper folding of mutant SOD1

Huntington's Disease

In HD pathogenesis:

Mutant [huntingtin](/proteins/huntingtin): HSP90AA1 can modulate mutant huntingtin aggregation
Transcription regulation: Client proteins include transcriptional regulators affected in HD

Therapeutic Implications

HSP90 Inhibitors

Several HSP90 inhibitors have been investigated:

Geldanamycin: Natural product that binds N-terminal pocket
17-AAG (Tanespimycin): Semi-synthetic derivative, clinical trials
PU-H71: Purine scaffold inhibitor
AT13387: Second-generation inhibitor

Challenges

系统性毒性: HSP90 inhibitors affect multiple organ systems
Client protein selectivity: Need for tissue/disease-specific targeting
Compensatory upregulation: Cellular stress response can reduce efficacy

Neuroprotective Strategies

Combination therapy: HSP90 inhibitors with other agents
Brain-penetrant derivatives: Improved CNS delivery
Allosteric modulators: Targeting middle domain or C-terminal domain

Interactions and Network

Co-chaperones

HSP90AA1 function requires numerous co-chaperones:

HSP70 (HSPA1A): Delivers client proteins to HSP90
HOP (STIP1): Adapter protein linking HSP70 and HSP90
CDC37: Kinase-specific co-chaperone
AHA1: Accelerates ATP hydrolysis
PP5 (PPP5C): Dephosphorylates HSP90

Protein Complexes

HSP90AA1 participates in:

CHIP complex: With HSP70 and E3 ligase CHIP for ubiquitination
IKK complex: With IKKα, IKKβ, NEMO for NF-κB activation
LRRK2 complex: Stabilizing mutant LRRK2

Summary

HSP90AA1 is a central molecular chaperone with critical roles in neuronal protein homeostasis. Its client protein network includes many proteins directly relevant to neurodegenerative diseases. While HSP90 inhibitors have shown pre-clinical promise, clinical translation remains challenging due to systemic toxicity. Understanding the neuron-specific functions of HSP90AA1 may lead to more targeted therapeutic approaches.

Background

The study of Hsp90Aa1 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

HSP90AA1 Protein

HSP90AA1 Protein

Introduction

HSP90AA1 Protein

Introduction

Overview [@hsp2023]

Basic Information

Structure

Normal Function

Protein Folding and Quality Control

Client Protein Network

ATPase Cycle

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis (ALS)

Huntington's Disease

Therapeutic Implications

HSP90 Inhibitors

Challenges

Neuroprotective Strategies

Interactions and Network

Co-chaperones

Protein Complexes

Summary

Background

See Also

Related Hypotheses