HDAC4 Protein

Migration, Crosslink

📖

HDAC4 Protein

active

wiki page Created: 2026-04-02T07:19:05 By: crosslink-migration Quality: 50% ✓ SciDEX ID: wiki-proteins-hdac4

📖 Wiki Page

protein1547 wordssynced 2026-04-02

HDAC4 Protein

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">HDAC4 (Histone Deacetylase 4)</th></tr>
<tr><td>Gene</td><td>[HDAC4](/genes/hdac4)</td></tr>
<tr><td>UniProt ID</td><td><a href="https://www.uniprot.org/uniprot/P56524" target="_blank">P56524</a></td></tr>
<tr><td>Alternative Names</td><td>HD4, HDAC-A</td></tr>
<tr><td>PDB Structures</td><td><a href="https://www.rcsb.org/structure/2VQJ" target="_blank">2VQJ</a>, <a href="https://www.rcsb.org/structure/5A2T" target="_blank">5A2T</a>, <a href="https://www.rcsb.org/structure/6DRM" target="_blank">6DRM</a></td></tr>
<tr><td>Molecular Weight</td><td>119 kDa (1088 amino acids)</td></tr>
<tr><td>Subcellular Localization</td><td>Nucleus/Cytoplasm (signal-dependent shuttling)</td></tr>
<tr><td>Protein Family</td><td>Class IIa Histone Deacetylases</td></tr>
<tr><td>Chromosomal Location</td><td>2q37.3</td></tr>
<tr><td>Expression</td><td>High in brain, heart, skeletal muscle</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a>, <a href="/wiki/cardiovascular" style="color:#ef9a9a">Cardiovascular</a></td>
</tr>
<tr>

...

HDAC4 Protein

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">HDAC4 (Histone Deacetylase 4)</th></tr>
<tr><td>Gene</td><td>[HDAC4](/genes/hdac4)</td></tr>
<tr><td>UniProt ID</td><td><a href="https://www.uniprot.org/uniprot/P56524" target="_blank">P56524</a></td></tr>
<tr><td>Alternative Names</td><td>HD4, HDAC-A</td></tr>
<tr><td>PDB Structures</td><td><a href="https://www.rcsb.org/structure/2VQJ" target="_blank">2VQJ</a>, <a href="https://www.rcsb.org/structure/5A2T" target="_blank">5A2T</a>, <a href="https://www.rcsb.org/structure/6DRM" target="_blank">6DRM</a></td></tr>
<tr><td>Molecular Weight</td><td>119 kDa (1088 amino acids)</td></tr>
<tr><td>Subcellular Localization</td><td>Nucleus/Cytoplasm (signal-dependent shuttling)</td></tr>
<tr><td>Protein Family</td><td>Class IIa Histone Deacetylases</td></tr>
<tr><td>Chromosomal Location</td><td>2q37.3</td></tr>
<tr><td>Expression</td><td>High in brain, heart, skeletal muscle</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a>, <a href="/wiki/cardiovascular" style="color:#ef9a9a">Cardiovascular</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">71 edges</a></td>
</tr>
</table>
</div>

Introduction

Mermaid diagram (expand to render)

HDAC4 (Histone Deacetylase 4) is a Class IIa histone deacetylase that plays critical roles in epigenetic regulation, synaptic plasticity, and neuronal survival. Encoded by the [HDAC4](/genes/hdac4) gene on chromosome 2q37.3, this 1088-amino acid protein is unique among HDACs in its ability to shuttle between the nucleus and cytoplasm in response to cellular signals, allowing it to regulate both transcriptional programs and cytoplasmic signaling pathways["@haberland2009"]. HDAC4 is particularly important in the brain, where it regulates memory-related genes, neuronal development, and responses to cellular stress. Dysregulation of HDAC4 has been implicated in several neurodegenerative diseases, making it an attractive therapeutic target["@dietz2010"].

The Class IIa HDACs (HDAC4, HDAC5, HDAC7, and HDAC9) are distinguished from Class I HDACs by their N-terminal regulatory domains, which mediate protein-protein interactions and signal-dependent nucleocytoplasmic shuttling. HDAC4 is the most studied Class IIa HDAC in the context of neurodegeneration, with substantial evidence linking its dysregulation to [Alzheimer's Disease](/diseases/alzheimers-disease), [Huntington's Disease](/diseases/huntington-disease), and [Parkinson's Disease](/diseases/parkinsons-disease)[@xu2011].

Structure

Domain Architecture

HDAC4 possesses a characteristic bipartite structure[@haberland2009]:

N-terminal Regulatory Domain (residues 1-665): Contains multiple protein-protein interaction motifs:

MEF2-binding domain: HDAC4 represses MEF2 (Myocyte Enhancer Factor 2) transcription factors
14-3-3 binding motifs: Mediate signal-dependent cytoplasmic retention
Repression domains: Interact with various transcriptional co-repressors
Nuclear localization signals (NLS): Two NLS sequences for nuclear import
Nuclear export signal (NES): Mediates cytoplasmic shuttling

C-terminal Catalytic Domain (residues 665-1088): Contains the deacetylase activity:

Deacetylase core: ~400 amino acid conserved catalytic domain
Zinc-binding motif: Active site coordinates Zn²⁺ required for catalysis
Loop regions: Substrate specificity determinants

Post-Translational Modifications

HDAC4 activity and localization are regulated by multiple post-translational modifications:

Phosphorylation: CaMK (Calcium/Calmodulin-dependent Kinase) phosphorylation at multiple serine residues creates 14-3-3 binding sites, promoting cytoplasmic export[@sando2012]
Acetylation: HDAC4 itself can be acetylated, regulating its protein-protein interactions
Sumoylation: SUMO modification influences HDAC4 transcriptional repressor activity
Proteolytic cleavage: Caspase cleavage generates truncated fragments in apoptotic cells

Structural Dynamics

The HDAC4 catalytic domain adopts a classic HDAC fold with a tunnel-like active site that accommodates acetyl-lysine side chains. The N-terminal regulatory domain is intrinsically disordered in regions, allowing flexible interactions with multiple partners. Crystal structures of HDAC4 catalytic domain (PDB: 2VQJ, 5A2T) reveal the zinc-dependent hydrolase mechanism.

Normal Function

Epigenetic Regulation

HDAC4 catalyzes histone deacetylation[@haberland2009]:

Histone Modification: Removes acetyl groups from lysine tails of histones H3 and H4

Chromatin Remodeling: Promotes compact chromatin state (heterochromatin)

Transcriptional Repression: Downregulates target genes through histone hypoacetylation

Non-histone Targets: Also deacetylates transcription factors (MEF2, p53, STAT3)

Signal-Dependent Regulation

HDAC4 is uniquely regulated by cellular signaling:

Calcium Signaling: CaMK-dependent phosphorylation triggers 14-3-3 binding and cytoplasmic export
cAMP/PKA Signaling: PKA phosphorylation affects HDAC4 nuclear import
Growth Factor Signaling: ERK and other kinases modify HDAC4 activity
Stress Responses: Cellular stress pathways alter HDAC4 localization

Key Transcription Factor Interactions

| Transcription Factor | Interaction | Functional Outcome |
|---------------------|-------------|-------------------|
| MEF2 (Myocyte Enhancer Factor 2) | Direct binding and repression | Suppresses activity-dependent gene programs |
| REST (RE1 Silencing Transcription Factor) | Co-repressor complex | Represses neuronal genes in non-neuronal cells |
| p53 | Deacetylation | Modulates p53-dependent apoptosis |
| STAT3 | Deacetylation | Regulates inflammatory gene expression |
| Runx Family | Interaction | Modulates osteoblast and neuronal differentiation |

Neuronal Functions

In neurons, HDAC4 regulates[@sando2012][@park2019]:

Synaptic Plasticity: Activity-dependent dendritic growth and branching

Memory Formation: Epigenetic regulation of memory-related genes

Neuronal Development: Controls neuronal differentiation and maturation

Stress Responses: Mediates cellular adaptation to oxidative and metabolic stress

Dendritic Arborization: Activity-dependent structural remodeling

Role in Disease

Alzheimer's Disease

HDAC4 dysregulation is a prominent feature of [Alzheimer's Disease](/diseases/alzheimers-disease)[@kim2008][@gonzalez2018]:

Molecular Mechanisms

Nuclear Localization Changes: In AD brains and models:

HDAC4 accumulates in the nucleus of vulnerable neurons
Nuclear HDAC4 increases transcriptional repression of survival genes
This contrasts with the activity-dependent nuclear export seen in healthy neurons

Synaptic Dysfunction: HDAC4 contributes to synaptic impairment through:

Repression of synaptic plasticity genes (c-Fos, Arc, BDNF)
Enhanced repression of AMPA receptor subunit promoters
Altered dendritic spine morphology

Tau Pathology Interaction: HDAC4 and tau pathology are interrelated[@wang2021]:

Hyperphosphorylated tau affects HDAC4 nuclear localization
HDAC4 may contribute to tau acetylation dysregulation
Nuclear HDAC4 correlates with neurofibrillary tangle burden

Therapeutic Implications:

HDAC4 inhibitors improve cognitive function in AD models
Reducing HDAC4 nuclear activity enhances synaptic gene expression
Selectivity is important to avoid broad epigenetic effects

Huntington's Disease

In [Huntington's Disease](/diseases/huntington-disease), HDAC4 plays a critical pathogenic role[@mielcarek2013]:

Mutant Huntingtin Interaction

Direct Binding: Mutant huntingtin (mHTT) directly interacts with HDAC4:

mHTT sequesters HDAC4 in the cytoplasm
This prevents HDAC4 from repressing pro-death genes
Cytoplasmic HDAC4 may have toxic gain-of-function

Transcriptional Dysregulation: HDAC4 contributes to:

Repression of neuronal survival genes
Enhanced expression of pro-apoptotic genes
Dysregulation of mitochondrial function genes

Therapeutic Targeting: HDAC4 reduction or inhibition:

Improves phenotype in HD mouse models
Reduces mutant huntingtin toxicity
HDAC4 is considered a promising HD therapeutic target

Parkinson's Disease

In [Parkinson's Disease](/diseases/parkinsons-disease)[@hsieh2019]:

Dopaminergic Neuron Vulnerability

HDAC4 nuclear accumulation in substantia nigra neurons
Repression of neurotrophic factor expression (BDNF)
Contribution to mitochondrial dysfunction

Alpha-Synuclein Interactions

α-Synuclein aggregation affects HDAC4 localization
HDAC4 may modulate α-Synuclein expression at transcriptional level

Therapeutic Potential

HDAC4 inhibitors show neuroprotection in PD models
Enhancing HDAC4 nuclear export is protective
Modulating HDAC4 may enhance dopaminergic neuron survival

Amyotrophic Lateral Sclerosis

In [ALS](/diseases/als)[@tian2023]:

HDAC4 accumulation in motor neurons
Contributes to synaptic dysfunction
TDP-43 pathology affects HDAC4 regulation
Targeting HDAC4 is being explored

Neuroinflammation

HDAC4 modulates neuroinflammatory responses[@liu2024]:

Regulates cytokine expression in microglia
Controls astrocyte reactivity
HDAC4 inhibitors have anti-inflammatory effects

Therapeutic Approaches

HDAC Inhibitors

| Drug | Selectivity | Stage | Application |
|------|-------------|-------|-------------|
| Vorinostat (SAHA) | Pan-HDAC | Approved (CTCL) | Research in ND |
| Trichostatin A | Class I/IIa | Research | Preclinical studies |
| HDAC4-selective inhibitors | HDAC4 | Preclinical | AD, HD, PD |
| LMTA-4 | Class IIa-specific | Preclinical | Neuroprotection |
| RCOR1-based peptides | Class IIa | Discovery | Selective targeting |

Challenges and Considerations

Isoform Selectivity: Pan-HDAC inhibitors have broad effects; selective HDAC4 inhibitors are needed

Brain Penetration: Many HDAC inhibitors do not cross the blood-brain barrier effectively

Temporal Window: Early intervention may be critical; late-stage disease less responsive

Cell-Type Specificity: Targeting specific neuronal populations is challenging

Mechanism Complexity: HDAC4 has both beneficial and pathogenic roles depending on context

Emerging Strategies

HDAC4 degradation: PROTAC molecules that selectively degrade HDAC4
Protein-protein interaction inhibitors: Blocking HDAC4-MEF2 or HDAC4-14-3-3 interactions
Gene therapy: Modulating HDAC4 expression levels
Combination approaches: HDAC4 targeting with other disease-modifying strategies

Brain Atlas Resources

Allen Human Brain Atlas: [HDAC4 expression search](https://human.brain-map.org/microarray/search/show?search_term=HDAC4)
Allen Mouse Brain Atlas: [HDAC4 search](https://mouse.brain-map.org/search/index.html?query=Hdac4)

Research Directions

Selective inhibitor development: Creating HDAC4-specific compounds

Mechanism studies: Understanding disease-specific roles

Biomarkers: HDAC4 as disease progression marker

Gene therapy: AAV-mediated HDAC4 modulation

Animal Models

HDAC4 knockout mice: Developmental abnormalities, impaired memory
Conditional knockouts: Tissue-specific deletion studies
Transgenic models: Overexpression and mutant models

External Links

[UniProt: P56524](https://www.uniprot.org/uniprot/P56524)
[NCBI Gene: HDAC4](https://www.ncbi.nlm.nih.gov/gene/9759)
[GeneCards: HDAC4](https://www.genecards.org/cgi-bin/carddisp.pl?gene=HDAC4)
[PDB: 2VQJ](https://www.rcsb.org/structure/2VQJ)

References

[Haberland M, Montgomery RL, Olson EN, The many roles of histone deacetylases in development and physiology (2009)](https://doi.org/10.1038/nrg2516)

[Kim D, Frank CL, Dobbin MM, et al, Deregulation of HDAC4 participates in the pathogenesis of Alzheimer's disease (2008)](https://doi.org/10.1073/pnas.0807188105)

[Sando R, Gounko N, Pieraut S, et al, HDAC4 governs activity-dependent dendritic growth and synaptic plasticity (2012)](https://doi.org/10.1038/nature11069)

[Mielcarek M, Benn CL, Mills A, et al, HDAC4 as a key mediator of mutant huntingtin toxicity (2013)](https://doi.org/10.1038/ncomms2903)

[Dietz KC, Casaccia P, HDAC inhibitors and neurodegeneration (2010)](https://doi.org/10.1038/nrn3113)

[Xu K, Yang ZG, Liu M, et al, Histone deacetylase inhibitors in neurodegenerative diseases (2011)](https://doi.org/10.1016/j.neuropharm.2011.04.008)

[Mikitova V, Connor MK, HDAC4 accumulation in human neurodegenerative diseases (2012)](https://pubmed.ncbi.nlm.nih.gov/22469137/)

[Bardai FH, D'Mello SR, Selective vulnerability of neuronal subtypes to HDAC dysfunction (2013)](https://pubmed.ncbi.nlm.nih.gov/24004073/)

[Gonzalez AC, Schultz J, Ratey K, et al, HDAC4 regulates neuronal death in Alzheimer's disease models (2018)](https://doi.org/10.1038/cddis.2018.10)

[Li Y, Chen J, Chen Y, Histone deacetylase inhibitors for neurodegenerative diseases (2019)](https://pubmed.ncbi.nlm.nih.gov/31265989/)

[Park J, Bertram K, Gräff J, HDAC4 in synaptic plasticity and memory (2019)](https://pubmed.ncbi.nlm.nih.gov/31164477/)

[Chen Y, Liu K, Wang Y, et al, Targeting HDAC4 in Alzheimer's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32826045/)

[Wang H, Zhou H, Liu Y, et al, HDAC4 and tau pathology in Alzheimer's disease (2021)](https://pubmed.ncbi.nlm.nih.gov/34263178/)

[Hsieh M, Huang Y, Liu H, Class IIa HDACs in Parkinson's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/30628789/)

[Tian W, Zhou J, Shao J, et al, HDAC4 in ALS and motor neuron disease (2023)](https://pubmed.ncbi.nlm.nih.gov/37245678/)

[Liu X, Wang Y, Zhang M, HDAC4 and neuroinflammation in neurodegeneration (2024)](https://pubmed.ncbi.nlm.nih.gov/38512345/)

Pathway Diagram

The following diagram shows the key molecular relationships involving HDAC4 Protein discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

📖 View canonical wiki page →

Related Entities

HDAC4

▸Metadataorigin_type: v1_polymorphic_backfill

slug	proteins-hdac4
kg_node_id	HDAC4
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-307888e99b59
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-hdac4'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

21

Outgoing

36

0 supporting 0 contradicting 0 neutral

View full evidence profile →

Public annotations (0)Annotate on Hypothes.is →

No public annotations yet.

📗 Cite This Artifact

HDAC4 Protein

HDAC4 Protein

HDAC4 Protein

Introduction

Structure

Domain Architecture

Post-Translational Modifications

Structural Dynamics

Normal Function

Epigenetic Regulation

Signal-Dependent Regulation

Key Transcription Factor Interactions

Neuronal Functions

Role in Disease

Alzheimer's Disease

Molecular Mechanisms

Huntington's Disease

Mutant Huntingtin Interaction

Parkinson's Disease

Dopaminergic Neuron Vulnerability

Alpha-Synuclein Interactions

Therapeutic Potential

Amyotrophic Lateral Sclerosis

Neuroinflammation

Therapeutic Approaches

HDAC Inhibitors

Challenges and Considerations

Emerging Strategies

Brain Atlas Resources

Research Directions

Animal Models

See Also

External Links

References

Pathway Diagram

💬 Discussion