DLAT Gene

title: DLAT - Dihydrolipoamide S-Acetyltransferase
category: gene

DLAT — Dihydrolipoamide S-Acetyltransferase

Introduction

DLAT (Dihydrolipoamide S-Acetyltransferase) encodes the E2 component of the pyruvate dehydrogenase complex (PDC), a critical metabolic enzyme linking glycolysis to the TCA cycle. This gene has garnered significant attention in neurodegenerative disease research due to the central role of glucose metabolism in neuronal function and the well-documented cerebral hypometabolism in Alzheimer's disease[@gibson2010][@blass2010].

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Dihydrolipoamide S-Acetyltransferase</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>DLAT</td></tr>
<tr><td><strong>Full Name</strong></td><td>Dihydrolipoamide S-Acetyltransferase</td></tr>
<tr><td><strong>Chromosome</strong></td><td>11q23.1</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[1737](https://www.ncbi.nlm.nih.gov/gene/1737)</td></tr>
<tr><td><strong>OMIM</strong></td><td>608770</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000150768</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P10515](https://www.uniprot.org/uniprot/P10515)</td></tr>
<tr><td><strong>Protein Class</strong></td><td>Metabolic Enzyme (E2 Component)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>[Alzheimer's Disease](/diseases/alzheimers-disease), Pyruvate Dehydrogenase Deficiency, Diabetes</td></tr>
</table>
</div>

title: DLAT - Dihydrolipoamide S-Acetyltransferase
category: gene

DLAT — Dihydrolipoamide S-Acetyltransferase

Introduction

DLAT (Dihydrolipoamide S-Acetyltransferase) encodes the E2 component of the pyruvate dehydrogenase complex (PDC), a critical metabolic enzyme linking glycolysis to the TCA cycle. This gene has garnered significant attention in neurodegenerative disease research due to the central role of glucose metabolism in neuronal function and the well-documented cerebral hypometabolism in Alzheimer's disease[@gibson2010][@blass2010].

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">Dihydrolipoamide S-Acetyltransferase</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>DLAT</td></tr>
<tr><td><strong>Full Name</strong></td><td>Dihydrolipoamide S-Acetyltransferase</td></tr>
<tr><td><strong>Chromosome</strong></td><td>11q23.1</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[1737](https://www.ncbi.nlm.nih.gov/gene/1737)</td></tr>
<tr><td><strong>OMIM</strong></td><td>608770</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000150768</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P10515](https://www.uniprot.org/uniprot/P10515)</td></tr>
<tr><td><strong>Protein Class</strong></td><td>Metabolic Enzyme (E2 Component)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>[Alzheimer's Disease](/diseases/alzheimers-disease), Pyruvate Dehydrogenase Deficiency, Diabetes</td></tr>
</table>
</div>

Overview

DLAT is the central structural and catalytic component of the pyruvate dehydrogenase complex, forming a 24-mer cubic core that organizes the entire complex["@patel2014"]. The complex consists of three main enzymatic components: E1 (pyruvate dehydrogenase, encoded by PDHA1 and PDHB), E2 (DLAT), and E3 (dihydrolipoamide dehydrogenase, encoded by DLD), along with regulatory enzymes E3BP and PDK. This multi-enzyme complex is embedded in the mitochondrial matrix and is essential for cellular energy production through aerobic respiration.

The pyruvate dehydrogenase complex catalyzes the oxidative decarboxylation of pyruvate to acetyl-CoA, the rate-limiting step that links glycolysis to the TCA cycle and oxidative phosphorylation. This reaction is fundamental to aerobic energy metabolism, and its dysfunction has profound consequences for cellular energetics, particularly in high-energy-demand tissues like the brain.

Gene Structure and Expression

Protein Architecture

The DLAT protein serves dual roles as both the structural scaffold and catalytic engine of the PDC. Each DLAT monomer consists of three distinct domains:

| Domain | Position | Function |
|--------|----------|----------|
| N-terminal lipoyl domain | 1-90 | Contains lipoyllysine for cofactor attachment |
| Peripheral subunit-binding domain | 91-200 | Binds E1 and E3 components |
| C-terminal catalytic domain | 201-647 | Catalyzes acetyl transfer to CoA |

The DLAT protein forms a 24-mer cubic core through dimerization of 12 identical subunits, creating a remarkable architectural feat that positions the catalytic sites optimally for substrate channeling between E1, E2, and E3 components[@patel2014].

Catalytic Mechanism

The acetyltransfer reaction proceeds through a series of intermediate steps:

This mechanism ensures efficient substrate channeling without release of intermediate products, maximizing metabolic efficiency.

Lipoylation: A Critical Post-Translational Modification

The lipoylation of DLAT is essential for its function. The lipoic acid cofactor, covalently attached to a lysine residue in the lipoyl domain, serves as a swinging arm that carries acetyl groups between the active sites of E1, E2, and E3. This process requires:

• Lipoic acid synthesis: De novo creation of the dithiolane ring
• Enzyme-mediated attachment: Lipoate-protein ligases (LPL) catalyze attachment
• Regeneration: Lipoate dehydrogenase regenerates oxidized lipoate

Role in Neuronal Energy Metabolism

Neurons are highly energy-dependent cells requiring continuous ATP production for:

• Maintenance of membrane potentials and ion gradients
• Neurotransmitter synthesis and release
• Cytoskeletal dynamics and axonal transport
• Synaptic plasticity processes
• Action potential propagation

The vulnerability of neuronal glucose metabolism to dysfunction makes PDC a critical node in understanding neurodegenerative processes.

Disease Associations

DLAT variants and expression changes are associated with several conditions:

Pyruvate Dehydrogenase Complex Deficiency

PDC deficiency is one of the most common inherited metabolic disorders of energy metabolism[@stacpoole2012]:

• Inheritance: Autosomal recessive
• Clinical Features: Lactic acidosis, metabolic encephalopathy, developmental delay, hypotonia, ataxia
• Mechanism: Loss-of-function mutations in DLAT reduce PDC activity below critical thresholds
• Treatment: Ketogenic diet as alternative energy source (bypasses PDC)
• Prognosis: Varies from severe neonatal onset to milder adult-onset forms

Alzheimer's Disease

DLAT shows significant downregulation in AD brains and is implicated in disease pathogenesis through multiple mechanisms[@gibson2010][@blass2010][@ding2013][@perez2019]:

Cerebral Hypometabolism:

• Reduced DLAT expression contributes to decreased glucose metabolism in AD
• FDG-PET studies consistently show reduced cerebral glucose uptake in AD
• The temporal pattern of hypometabolism correlates with regional vulnerability
• DLAT reduction is part of broader mitochondrial dysfunction

• Amyloid-beta oligomers may impair PDC function through direct interaction
• Mitochondrial Aβ accumulation correlates with reduced enzymatic activity
• Aβ-induced oxidative stress damages DLAT and other mitochondrial proteins

• Hyperphosphorylated tau correlates with reduced PDC activity
• Tau-mediated sequestration of mitochondrial proteins contributes to dysfunction
• The combination of Aβ and tau creates a synergistic metabolic deficit

• PDC activation is being explored as a therapeutic strategy
• Lipoic acid supplementation has shown cognitive benefits[@hauptmann2009]
• Ketogenic approaches may bypass metabolic deficits[@karim2020]

Diabetes and Metabolic Syndrome

• Altered PDC activity affects glucose homeostasis
• Insulin resistance associated with reduced PDC function
• Metabolic inflexibility in skeletal muscle and brain

Expression Patterns

Brain Distribution

DLAT is expressed throughout the brain with highest levels in regions with high metabolic demand:

| Brain Region | Expression Level | Significance |
|--------------|------------------|---------------|
| Cerebral Cortex | High | High synaptic density, elevated energy demand |
| Hippocampus | High | Memory formation, CA1 especially vulnerable in AD |
| Basal Ganglia | Moderate-High | Motor control, dopaminergic neuron maintenance |
| Cerebellum | High | Motor coordination, Purkinje cells |
| Brainstem | Moderate | Vital functions, cranial nerve nuclei |
| White Matter | Lower | Myelinated axons, lower metabolic activity |

Cellular Distribution

• Neurons: High expression in pyramidal neurons and interneurons
• Astrocytes: Moderate expression, support neuronal metabolism
• Oligodendrocytes: Lower expression, lipid synthesis support
• Microglia: Low baseline expression, increases in neuroinflammation

Regulation by Metabolic State

DLAT expression is regulated by:

• PGC-1α: Master regulator of mitochondrial biogenesis
• Thyroid hormone: Responsive to metabolic demands
• AMPK: Activated during energy stress
• Sirtuins: NAD+-dependent deacetylases affect activity

Interaction Network

DLAT interacts with multiple proteins within the mitochondrial metabolic network:

| Protein | Role | Interaction Type |
|---------|------|------------------|
| PDHA1 | E1α (pyruvate dehydrogenase) | Catalytic substrate binding |
| PDHB | E1β | Forms heterotetramer with PDHA1 |
| DLAT | Self | Forms 24-mer core through dimerization |
| DLD | E3 (dihydrolipoamide dehydrogenase) | Electron transfer |
| PDHX | E3BP | Alternative E3 binding protein |
| PDP1/PDP2 | Phosphatases | Regulatory dephosphorylation |
| PDK1/PDK2/PDK3 | Kinases | Regulatory phosphorylation |

These interactions coordinate the metabolic flux through the PDC, with kinase/phosphatase regulation providing rapid control of PDC activity in response to cellular energy demands[@perez2019][@sorrentino2017].

Regulation

DLAT activity is regulated at multiple levels:

Transcriptional Regulation

• PGC-1α: Coactivation drives mitochondrial biogenesis including DLAT
• Thyroid hormone: Responsive to metabolic demands
• AMPK: Activated during energy stress, increases expression
• Sirtuins: NAD+-dependent regulation of mitochondrial function

Post-Translational Regulation

| Modification | Effect | Enzyme |
|--------------|--------|--------|
| Phosphorylation | Inhibits PDC activity | PDK1/2/3 |
| Dephosphorylation | Activates PDC | PDP1/2 |
| Lipoylation | Essential for catalytic function | LPL family |
| Acetylation | Metabolic regulation | Acetyltransferases |

Allosteric Regulation

• Product inhibition: Acetyl-CoA inhibits DLAT activity
• Energy sensing: NADH/NAD+ ratio signals metabolic status
• Feedback: ATP/ADP ratio provides energy state feedback

Therapeutic Implications

Given the central role of DLAT in cellular metabolism, several therapeutic strategies are being explored[@hauptmann2009][@yang2011][@karim2020]:

Metabolic Modulation

Ketogenic Approaches

The ketogenic diet bypasses PDC by providing alternative fuel:

• ketone bodies are converted to acetyl-CoA independent of PDC
• Has shown benefits in some AD patients
• Particularly relevant for patients with PDC dysfunction

Gene Therapy and Protein Replacement

• Viral vector delivery of functional DLAT
• Enzyme replacement therapy (in development)
• Small molecule correctors of lipoylation defects

Mitochondrial Biogenesis

• PGC-1α activators increase DLAT expression
• AMPK agonists promote mitochondrial health
• Sirtuin activators enhance metabolic function

Key Publications

See Also

• [DLAT Protein](/proteins/dlat) - Protein page
• [Alzheimer's Disease Mechanisms](/mechanisms/alzheimers-disease) - AD pathway mechanisms
• [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction) - Mitochondrial mechanisms
• [Glucose Metabolism](/mechanisms/brain-glucose-metabolism) - Brain energy metabolism
• [Pyruvate Dehydrogenase Complex](/mechanisms/pyruvate-dehydrogenase-complex) - PDC mechanisms

External Links

• [GeneCards - DLAT](https://www.genecards.org/cgi-bin/carddisp.pl?gene=DLAT)
• [UniProt - DLAT](https://www.uniprot.org/uniprot/P10515)
• [NCBI Gene - DLAT](https://www.ncbi.nlm.nih.gov/gene/1737)
• [OMIM - DLAT](https://www.omim.org/entry/608770)
• [Ensembl - DLAT](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000150768)

Pathway Diagram

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