GABA-A Alpha-4 Protein — GABA-A Receptor Alpha 4 Subunit

GABA-A Alpha-4 Protein

<table class="infobox infobox-protein">
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<th class="infobox-header" colspan="2">GABA-A Alpha-4 Protein — GABA-A Receptor Alpha 4 Subunit</th>
</tr>
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<td class="label">Symbol</td>
<td><strong>GABRA4</strong></td>
</tr>
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<td class="label">Full Name</td>
<td>GABA-A Alpha-4 — GABA-A Receptor Alpha 4 Subunit</td>
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<td class="label">Type</td>
<td>Protein</td>
</tr>
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<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=GABRA4" target="_blank">Search UniProt</a></td>
</tr>
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<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
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</table>

Introduction

Gaba A Alpha 4 Protein — Gaba A Receptor Alpha 4 Subunit is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

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GABA-A Alpha-4 Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">GABA-A Alpha-4 Protein — GABA-A Receptor Alpha 4 Subunit</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>GABRA4</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>GABA-A Alpha-4 — GABA-A Receptor Alpha 4 Subunit</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=GABRA4" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

Introduction

Gaba A Alpha 4 Protein — Gaba A Receptor Alpha 4 Subunit is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

GABRA4 is a subunit of the GABA-A receptor, a ligand-gated chloride channel that mediates inhibitory neurotransmission in the central nervous system. The alpha-4 subunit is encoded by the GABRA4 gene located on chromosome 4p12 and is predominantly expressed in the thalamus and [cortex](/brain-regions/cortex). GABA-A receptors containing the alpha-4 subunit have distinct pharmacological properties and are involved in regulating neuronal excitability, anxiety, and memory processes. These receptors are targets for benzodiazepines, neurosteroids, and various anxiolytic and anticonvulsant drugs.

Structure

GABRA4 contains:

• Extracellular N-terminal domain: Contains the benzodiazepine binding site
• Transmembrane domains: Four transmembrane helices forming the channel pore
• Intracellular loop: Contains sites for phosphorylation and trafficking signals
• C-terminal domain: Important for receptor assembly and localization

Molecular Function

Chloride Channel Function

GABRA4-containing GABA-A receptors mediate fast inhibitory neurotransmission:

GABA binding: GABA binds to the extracellular interface between alpha and beta subunits

Conformational change: Binding triggers channel opening

Chloride flux: Cl- ions flow into the neuron, hyperpolarizing the membrane

Inhibition: Reduced neuronal excitability

Pharmacological Properties

• Benzodiazepine sensitivity: Alpha-4-containing receptors have reduced benzodiazepine sensitivity
• Neurosteroid modulation: Highly sensitive to neurosteroid modulation
• Ethanol effects: Involved in ethanol's effects on inhibition

Expression Pattern

GABRA4 is expressed in:

• Thalamus (high expression)
• Cerebral cortex (layers I-IV)
• [Hippocampus](/brain-regions/hippocampus) (CA1-CA3)
• Basal ganglia
• Spinal cord

Disease Associations

Epilepsy

GABRA4 variants are associated with epilepsy:

• Genetic mutations can cause epileptic encephalopathy
• Altered receptor function contributes to seizure susceptibility
• Therapeutic targeting of alpha-4-containing receptors

Alzheimer's Disease

• GABAergic signaling is impaired in AD
• Alpha-4 subunit expression changes in AD
• Therapeutic implications for GABAergic drugs

Parkinson's Disease

• Altered GABAergic signaling in PD
• Deep brain stimulation affects GABAergic circuits
• Potential therapeutic target

Anxiety Disorders

• Alpha-4-containing receptors mediate anxiolytic effects
• Dysregulation associated with anxiety
• Target for novel anxiolytic drugs

Therapeutic Implications

Drug Targets

Benzodiazepines: Though alpha-4 has reduced sensitivity, some compounds are selective

Neurosteroids: Positive allosteric modulators

Novel compounds: Selective alpha-4 modulators in development

See Also

• [GABRA4 Gene](/proteins/gabra4-protein)
• [GABA-A Receptor](/proteins/gaba-a-receptor)
• [Inhibitory Neurotransmission](/mechanisms/gaba-signaling)

Background

The study of Gaba A Alpha 4 Protein — Gaba A Receptor Alpha 4 Subunit 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.

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
• [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

Molecular Mechanisms

The GABA-A Alpha-4 subunit (GABRA4) is a component of the GABA-A receptor, a ligand-gated chloride channel that mediates fast inhibitory neurotransmission in the central nervous system. The Alpha-4 subunit is primarily expressed in the thalamus and dentate gyrus of the hippocampus, brain regions critical for sensory processing and memory formation.

GABA-A receptors containing the Alpha-4 subunit exhibit distinct pharmacological properties, including reduced sensitivity to benzodiazepines and distinctive patterns of modulation by neurosteroids. These receptors are often located extrasynaptically, where they respond to ambient GABA concentrations and mediate tonic inhibition.

Disease Associations

Alzheimer's Disease: GABRA4 expression is altered in Alzheimer's disease, particularly in the hippocampus. Changes in Alpha-4 containing receptors may contribute to network hyperexcitability and seizure activity observed in some AD patients. The subunit may also be involved in hippocampal memory circuits.

Parkinson's Disease: GABA-A Alpha-4 receptors are implicated in basal ganglia circuitry and may influence motor control. Altered receptor expression could contribute to motor complications in PD, including dyskinesias.

Epilepsy: GABRA4 mutations have been linked to epilepsy syndromes, highlighting the importance of this subunit in controlling neuronal excitability. The subunit's role in thalamocortical circuits is particularly relevant for absence seizures.

Therapeutic Implications

Targeting GABA-A receptors containing the Alpha-4 subunit may provide therapeutic benefits for conditions involving network hyperexcitability. However, the subunit's distinct pharmacology makes it challenging to develop selective modulators.

Research Directions

Research focuses on understanding the specific roles of Alpha-4 containing receptors in brain circuits and developing subunit-selective modulators.

References

Möhler et al, (2002) Nat Rev Neurosci 3:413-425 (2002)

Rudolph et al, (2001) Nature 401:796-800 (2001)