HSP90AA1 Protein

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

<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.

--- [@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

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:

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.

See Also

• [Neurodegenerative Diseases - Overview of disease category](/diseases/neurodegeneration)
• [Cell Types - Index of cell type pages](/cell-types)
• [Genes - Index of gene pages](/genes)
• [Proteins - Index of protein pages](/proteins)
• [Mechanisms - Index of mechanism pages](/mechanisms)

Related Hypotheses

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

• [HSP90-Tau Disaggregation Complex Enhancement](/hypothesis/h-0f00fd75) — <span style="color:#ffd54f;font-weight:600">0.53</span> · Target: HSP90AA1
• [Chaperone-Mediated APOE4 Refolding Enhancement](/hypothesis/h-637a53c9) — <span style="color:#ffd54f;font-weight:600">0.48</span> · Target: HSPA1A, HSP90AA1, DNAJB1, FKBP5