KAT8 Protein

KAT8 Protein

KAT8 (K(lysine) Acetyltransferase 8) Protein

<div class="infobox infobox-protein">
<div class="infobox-header">KAT8 (K(lysine) Acetyltransferase 8, MYST)</div>

Overview

KAT8 is a protein encoded by the [KAT8](/genes/kat8) gene that kat8 regulates gene expression through histone acetylation:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.

<div class="infobox-content">
<div class="infobox-row"><span class="infobox-label">Gene</span><span class="infobox-value">[KAT8](/genes/kat8)</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[Q9H7Z4](https://www.uniprot.org/uniprot/Q9H7Z4)</span></div>
<div class="infobox-row"><span class="infobox-label">PDB Structures</span><span class="infobox-value">5DJI, 5THB, 6CTO</span></div>
<div class="infobox-row"><span class="infobox-label">Molecular Weight</span><span class="infobox-value">52 kDa</span></div>
<div class="infobox-row"><span class="infobox-label">Subcellular Localization</span><span class="infobox-value">Nucleus</span></div>
<div class="infobox-row"><span class="infobox-label">Protein Family</span><span class="infobox-value">MYST histone acetyltransferase family</span></div>
</div>
</div>

Introduction

KAT8 Protein

KAT8 (K(lysine) Acetyltransferase 8) Protein

<div class="infobox infobox-protein">
<div class="infobox-header">KAT8 (K(lysine) Acetyltransferase 8, MYST)</div>

Overview

KAT8 is a protein encoded by the [KAT8](/genes/kat8) gene that kat8 regulates gene expression through histone acetylation:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.

<div class="infobox-content">
<div class="infobox-row"><span class="infobox-label">Gene</span><span class="infobox-value">[KAT8](/genes/kat8)</span></div>
<div class="infobox-row"><span class="infobox-label">UniProt ID</span><span class="infobox-value">[Q9H7Z4](https://www.uniprot.org/uniprot/Q9H7Z4)</span></div>
<div class="infobox-row"><span class="infobox-label">PDB Structures</span><span class="infobox-value">5DJI, 5THB, 6CTO</span></div>
<div class="infobox-row"><span class="infobox-label">Molecular Weight</span><span class="infobox-value">52 kDa</span></div>
<div class="infobox-row"><span class="infobox-label">Subcellular Localization</span><span class="infobox-value">Nucleus</span></div>
<div class="infobox-row"><span class="infobox-label">Protein Family</span><span class="infobox-value">MYST histone acetyltransferase family</span></div>
</div>
</div>

Introduction

KAT8 (also known as MYST1, MOZ, or HBO1) is a critical histone acetyltransferase (HAT) that catalyzes the addition of acetyl groups to lysine residues on histone proteins. As a member of the MYST family of HATs, KAT8 plays essential roles in transcriptional regulation, DNA damage response, cell cycle control, and synaptic plasticity. The protein is encoded by the KAT8 gene located on chromosome 16q24.1 and is expressed ubiquitously with particularly high levels in the brain, where it participates in neuronal development, cognition, and behavior.

KAT8's enzymatic activity centers on the acetylation of histone H4 at lysine 16 (H4K16ac), a modification that is fundamental to chromatin dynamics and gene expression. H4K16ac is a key epigenetic mark that regulates chromatin accessibility, facilitating transcriptional activation and replication origin firing. The loss of H4K16ac is a hallmark of aging and has been implicated in multiple neurodegenerative conditions, particularly Alzheimer's disease.

Structure

KAT8 is a histone acetyltransferase (458 amino acids) with:

• N-terminal MYST domain (catalytic): Contains the HAT activity and mediates substrate recognition
• C-terminal region for complex formation: Engages in protein-protein interactions essential for target specificity
• Zinc finger domain (C2HC-type): Involved in DNA binding and chromatin targeting
• Forms the MSL1v1 complex for H4K16 acetylation: The MSL (Male-Specific Lethal) complex comprises KAT8, MSL1, MSL2, MSL3, and MOF, directing H4K16ac to specific genomic loci

Structural Features

The MYST domain of KAT8 adopts a characteristic fold that positions the coenzyme A binding pocket and the catalytic residue (a glutamate that functions as a general base). The C2HC-type zinc finger, unique among human MYST proteins in KAT8, contributes to chromatin targeting through interactions with specific DNA sequences and nucleosomal architecture.

Crystal structures of the KAT8 catalytic domain (PDB: 5DJI, 5THB, 6CTO) have revealed the molecular basis for substrate recognition and provided insights for developing small molecule inhibitors and activators.

Normal Function

KAT8 regulates gene expression through histone acetylation:

• Histone acetylation: Catalyzes H4K16 acetylation (H4K16ac), the primary mark for chromatin decompaction
• Transcriptional regulation: Opens chromatin structure to facilitate RNA polymerase II access
• DNA damage response: Role in checkpoint activation and homologous recombination repair
• Cell cycle: Controls cell cycle progression through replication origin activation
• Synaptic plasticity: Regulates activity-dependent gene expression required for learning and memory

Neural Functions

Within the nervous system, KAT8 performs several specialized functions:

Role in Neurodegeneration

Alzheimer's Disease

• KAT8 is an AD risk gene: Genome-wide association studies have identified KAT8 variants that modify Alzheimer's disease risk, particularly in early-onset cases[@kat8ad2023]
• Dysregulated histone acetylation in AD brain: Postmortem AD brain tissue shows reduced H4K16ac levels that correlate with cognitive impairment[@histoneacetylation2022]
• H4K16ac levels reduced in AD: The enzymatic activity of KAT8 and other HATs is compromised in AD, contributing to transcriptional dysregulation
• Epigenetic therapy targets for cognitive decline: HDAC inhibitors that increase H4K16ac have shown promise in AD models, though targeting KAT8 directly remains an emerging strategy[@epigeneticherapy2024]
• May affect [APP](/entities/app-protein) transcription: KAT8 regulates APP expression through direct promoter acetylation, linking amyloid metabolism to epigenetic regulation

Parkinson's Disease

Emerging evidence suggests KAT8 may play protective roles in dopaminergic neurons:

• KAT8 expression is reduced in the substantia nigra of PD patients
• KAT8-mediated H4K16ac protects against alpha-synuclein toxicity
• The protein participates in mitochondrial quality control through transcriptional regulation

Rett Syndrome

• KAT8 mutations cause X-linked neurodevelopmental disorders: De novo missense mutations in KAT8 cause a Rett-like syndrome with intellectual disability, regression, and motor dysfunction[@rett2021]
• Essential for neuronal development: KAT8 is required for proper cortical development and neuronal maturation
• Interaction with MeCP2: KAT8 and methyl-CpG binding protein 2 (MeCP2) function in overlapping transcriptional pathways

Amyotrophic Lateral Sclerosis (ALS)

• KAT8 dysfunction contributes to RNA metabolism deficits in ALS
• The protein participates in stress granule formation and clearance
• Genetic variants in KAT8 modify ALS progression in some cohorts

Therapeutic Targeting

Epigenetic Therapy Approaches

The reversibility of histone acetylation makes KAT8 an attractive therapeutic target:

Biomarkers

• H4K16ac levels in peripheral blood mononuclear cells correlate with brain acetylation status
• KAT8 expression in cerebrospinal fluid as a potential biomarker
• Neuroimaging-based assessment of chromatin accessibility (emerging)

Key Publications

Cross-References

• [KAT8 Gene](/genes/kat8)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Epigenetic Regulation](/mechanisms/epigenetic-regulation)
• [Histone Acetylation](/mechanisms/histone-acetylation)
• [Chromatin Remodeling](/mechanisms/chromatin-remodeling)
• [Gene Transcription](/mechanisms/gene-transcription)
• [Parkinson's Disease](/diseases/parkinsons-disease)

See Also

• KAT8 Gene
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Epigenetic Regulation](/mechanisms/epigenetic-regulation)
• Histone Acetylation
• [Chromatin Remodeling](/mechanisms/chromatin-remodeling)
• Gene Transcription

External Links

• [UniProt: Q9H7Z4](https://www.uniprot.org/uniprot/Q9H7Z4)
• [PDB structures](https://www.rcsb.org/search?q=uniprot:Q9H7Z4)
• [GeneCards: KAT8](https://www.genecards.org/cgi-bin/carddisp.pl?gene=KAT8)

References