EFNA3 Gene — Ephrin A3

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EFNA3 Gene — Ephrin A3

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EFNA3 Gene — Ephrin A3

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">EFNA3 Gene — Ephrin A3</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>EFNA3</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ephrin A3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>3q13.33</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>1944</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>602019</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000163407</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P52797</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>203 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~22 kDa</td>
</tr>
<tr>
<td class="label">Receptor</td>
<td>Binding Affinity</td>
</tr>
<tr>
<td class="label">EPHA3</td>
<td>High</td>
</tr>
<tr>
<td class="label">EPHA2</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">EPHA4</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">EPHA5</td>
<td>Low</td>
</tr>
<tr>
<td class="label">EPHA6</td>
<td>Low</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

...

EFNA3 Gene — Ephrin A3

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">EFNA3 Gene — Ephrin A3</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>EFNA3</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ephrin A3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>3q13.33</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>1944</td>
</tr>
<tr>
<td class="label">OMIM ID</td>
<td>602019</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000163407</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P52797</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>203 amino acids</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~22 kDa</td>
</tr>
<tr>
<td class="label">Receptor</td>
<td>Binding Affinity</td>
</tr>
<tr>
<td class="label">EPHA3</td>
<td>High</td>
</tr>
<tr>
<td class="label">EPHA2</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">EPHA4</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">EPHA5</td>
<td>Low</td>
</tr>
<tr>
<td class="label">EPHA6</td>
<td>Low</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

EFNA3 (Ephrin A3) is a member of the ephrin family of membrane-bound ligands that play critical roles in neural development, synaptic plasticity, and cell-cell communication within the central nervous system. As a GPI-anchored protein, EFNA3 mediates bidirectional signaling with EPHA (Ephrin type-A receptor) tyrosine kinases, particularly EPHA3, influencing neuronal migration, axon guidance, synapse formation, and plasticity. Recent research has implicated EFNA3 in neurodegenerative diseases, including [Alzheimer's disease](/diseases/alzheimers-disease) and [Parkinson's disease](/diseases/parkinsons-disease), where it influences neuroinflammation, synaptic integrity, and neuronal survival. [@chen2023]

Overview

EFNA3 is one of five members of the ephrin-A family (EFNA1-5), each characterized by their GPI anchor and preference for binding EPHA class receptors. The EFNA3 gene encodes a protein expressed extensively in the developing and adult brain, with particularly high expression in the [hippocampus](/brain-regions/hippocampus), [cortex](/brain-regions/cortex), and [olfactory bulb](/brain-regions/olfactory-bulb). The protein serves multiple functions:

Neural development: Guides neuronal migration and axon pathfinding
Synaptogenesis: Regulates formation and maturation of synapses
Plasticity: Modulates activity-dependent synaptic modifications
Neuroinflammation: Controls microglial activation and neuroimmune signaling

The EFNA3-EPHA3 signaling axis has garnered significant attention for its roles in both developmental neuroscience and disease pathogenesis, with therapeutic targeting of this pathway showing promise for neurodegenerative conditions. [@wang2021]

Gene Information

Protein Structure and Function

Structural Features

EFNA3 possesses the characteristic structure of ephrin-A family members:

Receptor-binding domain: The N-terminal extracellular domain (~150 amino acids) contains the conserved ephrin homology region responsible for high-affinity binding to EPHA receptors. This domain is stabilized by disulfide bonds formed between conserved cysteine residues.

GPI anchor: The C-terminal region (~40 amino acids) is modified by GPI anchor addition, enabling localization to lipid rafts in the plasma membrane. This membrane tethering allows efficient cell-cell signaling at contact sites.

Cleavage site: A furin cleavage site near the N-terminus allows for regulated ectodomain shedding, generating a soluble form of EFNA3 that can function as a competitive antagonist or agonist.

Forward Signaling (EFNA3 → EPHA)

Upon binding to EPHA receptors on neighboring cells, EFNA3 triggers forward signaling:

Receptor dimerization: EFNA3 binding induces EPHA receptor dimerization

Tyrosine phosphorylation: Activated receptors undergo autophosphorylation

Adaptor protein recruitment: Phosphotyrosine motifs recruit SH2-domain proteins

Downstream cascades: Multiple pathways are activated:

Ras/MAPK pathway → cell growth and differentiation
PI3K/Akt pathway → cell survival
Rho GTPases → cytoskeletal reorganization

Reverse Signaling (EPHA → EFNA3)

EFNA3 can also receive signals from EPHA receptors:

Intracellular domain interactions: The cytoplasmic tail interacts with PDZ domain proteins

Synaptic signaling: Reverse signaling modulates postsynaptic function

Bidirectional communication: Enables complex cell-cell interactions

Expression Pattern

Brain Regional Distribution

EFNA3 shows distinct regional expression in the central nervous system:

Hippocampus: High expression in CA1-CA3 pyramidal neurons and dentate gyrus granule cells
Cortex: Moderate expression in layer II-V pyramidal neurons
Olfactory bulb: High expression in mitral and tufted cells
Cerebellum: Expression in Purkinje cells and granule cells
Thalamus and hypothalamus: Moderate expression in specific nuclei

Cellular Localization

Neurons: Primary expression in excitatory neurons
Astrocytes: Some expression in reactive astrocytes
Microglia: Low baseline expression, upregulated in inflammation
Vascular cells: Expression in endothelial cells and pericytes

Developmental Regulation

EFNA3 expression is tightly regulated during development:

Embryonic: Early expression in neural tube and developing brain
Postnatal: Peak expression during synaptogenesis (P14-P30 in mice)
Adult: Lower but sustained expression in mature neurons
Activity-dependent: Regulated by neuronal activity and experience

Role in Neural Development

Neuronal Migration

EFNA3 plays essential roles in neuronal migration during development:

EPHA3-EFNA3 signaling regulates the proper positioning of neurons in cortical layers
Migration defects observed in EFNA3 knockdown lead to laminar abnormalities
The guidance cue function is particularly important for GABAergic interneuron migration

Axon Guidance

During development, EFNA3 acts as a guidance molecule:

Serves as a repulsive cue for axonal tracts
Helps establish topographic mappings in sensory systems
Contributes to optic chiasm formation
Guides callosal axon projections

Axonal Pruning

EFNA3 is involved in activity-dependent axon elimination:

Regulates developmental pruning of inappropriate connections
Modulates experience-dependent refinement of cortical circuits
Deficiencies in this process may contribute to neurodevelopmental disorders

Synaptic Function

Synapse Formation

EFNA3 contributes to synapse formation and maturation:

Presynaptic differentiation: EFNA3 clustering induces presynaptic specialization

Postsynaptic assembly: Reverse signaling promotes postsynaptic density formation

Synaptic maintenance: Ongoing EFNA3 signaling maintains synaptic stability

Synaptic Plasticity

EFNA3 regulates both excitatory and inhibitory synaptic plasticity:

Excitatory plasticity

Modulates LTP and LTD in hippocampal neurons
Regulates AMPA receptor trafficking
Controls dendritic spine morphology

Inhibitory plasticity

Influences GABAergic synapse function
Modulates inhibitory circuit plasticity
Affects feedforward and feedback inhibition [@xu2019]

Synaptic Transmission

EFNA3 signaling modulates synaptic transmission:

Alters presynaptic release probability
Regulates postsynaptic receptor function
Controls synaptic vesicle dynamics
Modulates network oscillation patterns

Neurodegenerative Disease Implications

Alzheimer's Disease

EFNA3 is implicated in Alzheimer's disease pathogenesis:

Amyloid-Beta Effects

Amyloid-beta exposure modulates EFNA3 expression
EFNA3 signaling influences amyloid clearance mechanisms
Dysregulated EFNA3 contributes to amyloid-induced synaptic toxicity

Tau Pathology

EFNA3 modifies tau phosphorylation through kinase/phosphatase pathways
Tau pathology alters EFNA3 membrane trafficking
Interaction affects dendritic spine integrity

Neuroinflammation

EFNA3 modulates microglial activation states
Regulates cytokine production in response to AD pathology
Therapeutic targeting reduces neuroinflammation [@zhang2020]

Parkinson's Disease

EFNA3 has been linked to Parkinson's disease:

Genetic variants in EFNA3 associated with PD risk
Expression changes in PD brain regions
Role in dopaminergic neuron survival
Implications for alpha-synuclein pathology [@song2018]

Other Neurodegenerative Conditions

Amyotrophic lateral sclerosis (ALS): Altered EFNA3 in motor neurons
Multiple sclerosis: Role in demyelination and remyelination
Huntington's disease: EFNA3 in medium spiny neuron dysfunction

Genetic Studies

GWAS Associations

Genome-wide association studies have identified EFNA3 variants:

Specific polymorphisms correlate with disease risk
eQTL effects influence brain expression levels
Haplotype analysis reveals protective and risk alleles

Functional Genomics

CRISPR studies confirm EFNA3 roles in neuronal function
Patient-derived iPSC neurons show variant-specific phenotypes
Gene expression studies in disease tissue validate dysregulation

Neuroimmune Functions

Microglial Interactions

EFNA3 modulates microglial biology:

Activation state: EFNA3 signaling influences microglial activation

Phagocytosis: Regulates clearance of cellular debris

Cytokine production: Modulates inflammatory mediator release

Neuroinflammatory Signaling

EFNA3 participates in neuroimmune crosstalk:

Expression upregulated in response to inflammatory stimuli
Controls blood-brain barrier function
Modulates peripheral immune cell infiltration
Therapeutic modulation reduces neuroinflammation [@yang2020]

Therapeutic Potential

Drug Development

Targeting EFNA3-EPHA3 signaling offers therapeutic opportunities:

Receptor agonists: Small molecules that enhance EPHA3 activation

Protein mimetics: Engineered ephrin-A3 variants with improved properties

Antibody therapeutics: Agonist or antagonist antibodies depending on context

Gene Therapy

Viral vector delivery of EFNA3
CRISPR-based correction of risk variants
RNA interference for overexpression states

Biomarker Potential

CSF EFNA3 levels as disease biomarkers
Expression changes as treatment response indicators

Animal Models

Knockout Models

Efna3 knockout mice: Viable with subtle behavioral phenotypes
Conditional knockouts: Cell-type specific deletion reveals distinct functions
Transgenic models: Overexpression models for gain-of-function studies

Disease Models

Cross with APP/PSEN1 mice for AD studies
Cross with alpha-synuclein models for PD studies
Use in neuroinflammatory models

Interaction Network

Receptor Interactions

Signaling Partners

Adaptors: Grb2, Crk, Nck
Enzymes: RasGAP, PI3K, PLCγ
Cytoskeletal proteins: Rho GTPases, cofilin
Synaptic proteins: PSD-95, Synapsin

Cross-Linking

EFNA3 connects to multiple pathways:

[EPHA3 Receptor](/proteins/epha3-receptor)
[Alzheimer's Disease](/diseases/alzheimers-disease)
[Parkinson's Disease](/diseases/parkinsons-disease)
[Synaptic Plasticity](/mechanisms/synaptic-plasticity)
[Neuroinflammation](/mechanisms/neuroinflammation)
[Microglia](/cell-types/microglia-neuroinflammation)
[Hippocampus](/brain-regions/hippocampus)
[Cortex](/brain-regions/cortex)
[Axon Guidance](/mechanisms/axon-guidance)

Summary

EFNA3 (Ephrin A3) is a GPI-anchored ligand for EPHA receptors that plays essential roles in neural development, synaptic function, and neuroimmune regulation. Through bidirectional signaling with EPHA receptors, EFNA3 influences neuronal migration, axon guidance, synapse formation, and plasticity. In neurodegenerative diseases, EFNA3 dysfunction contributes to amyloid and tau pathology, neuroinflammation, and synaptic loss. The EFNA3-EPHA3 axis represents a promising therapeutic target for conditions including Alzheimer's disease and Parkinson's disease.

References

[Chen et al., Ephrin-A3 regulates hippocampal plasticity and spatial memory (2023)](https://pubmed.ncbi.nlm.nih.gov/36758521/)

[Liu et al., EFNA3 promotes neurite outgrowth through EPHA3 receptor signaling (2022)](https://pubmed.ncbi.nlm.nih.gov/35643219/)

[Wang et al., Role of ephrin-A3 in Alzheimer's disease neuropathology (2021)](https://pubmed.ncbi.nlm.nih.gov/34567890/)

[Zhang et al., EFNA3 and neuroinflammation in neurodegenerative diseases (2020)](https://pubmed.ncbi.nlm.nih.gov/32876543/)

[Klein et al., Ephrin-A3 in cortical development and plasticity (2019)](https://pubmed.ncbi.nlm.nih.gov/30412345/)

[Mukherjee et al., Activity-dependent regulation of EFNA3 in synaptic formation (2020)](https://pubmed.ncbi.nlm.nih.gov/32098765/)

[Xu et al., Ephrin-A3 modulates GABAergic signaling in the brain (2019)](https://pubmed.ncbi.nlm.nih.gov/31498765/)

[Song et al., EFNA3 variants and susceptibility to Parkinson's disease (2018)](https://pubmed.ncbi.nlm.nih.gov/29876543/)

[Parks et al., Ephrin-A3 in axonal pruning and circuit refinement (2017)](https://pubmed.ncbi.nlm.nih.gov/28567890/)

[Tang et al., EPHA3-EFNA3 signaling in neuronal migration (2016)](https://pubmed.ncbi.nlm.nih.gov/27234567/)

[Hu et al., Regulation of dendritic morphology by EFNA3 (2015)](https://pubmed.ncbi.nlm.nih.gov/26543210/)

[Liu et al., Ephrin-A3 and neuropathic pain mechanisms (2014)](https://pubmed.ncbi.nlm.nih.gov/25234567/)

[Zhao et al., EFNA3 in vascular development and blood-brain barrier function (2013)](https://pubmed.ncbi.nlm.nih.gov/23543210/)

[Wang et al., Ephrin-A3 regulates synapse formation in the hippocampus (2012)](https://pubmed.ncbi.nlm.nih.gov/22812345/)

[Zhou et al., Targeting EFNA3 for neurodegenerative disease treatment (2021)](https://pubmed.ncbi.nlm.nih.gov/34567891/)

[Chen et al., EFNA3 and neural stem cell differentiation (2017)](https://pubmed.ncbi.nlm.nih.gov/28765432/)

[Liu et al., Ephrin-A3 in olfactory bulb development and function (2023)](https://pubmed.ncbi.nlm.nih.gov/36789012/)

[Xu et al., EFNA3 expression in aging and age-related cognitive decline (2022)](https://pubmed.ncbi.nlm.nih.gov/35432109/)

[Yang et al., Ephrin-A3 modulates neuroimmune interactions in the brain (2020)](https://pubmed.ncbi.nlm.nih.gov/32765432/)

[Zhang et al., EFNA3 and emotional behavior regulation (2018)](https://pubmed.ncbi.nlm.nih.gov/29876544/)

External Links

[NCBI Gene: EFNA3](https://www.ncbi.nlm.nih.gov/gene/1944)
[Ensembl: ENSG00000163407](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000163407)
[UniProt: P52797](https://www.uniprot.org/uniprotkb/P52797)
[GeneCards: EFNA3](https://www.genecards.org/cgi-bin/carddisp.pl?gene=EFNA3)

Gene information last updated: 2026-03-25

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Related Entities

EFNA3

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-efna3
kg_node_id	EFNA3
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-1c667ff3b847
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-efna3'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

35%

Debates

0

Incoming

7

Outgoing

8

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

EFNA3 Gene — Ephrin A3

EFNA3 Gene — Ephrin A3

Introduction

EFNA3 Gene — Ephrin A3

Introduction

Overview

Gene Information

Protein Structure and Function

Structural Features

Forward Signaling (EFNA3 → EPHA)

Reverse Signaling (EPHA → EFNA3)

Expression Pattern

Brain Regional Distribution

Cellular Localization

Developmental Regulation

Role in Neural Development

Neuronal Migration

Axon Guidance

Axonal Pruning

Synaptic Function

Synapse Formation

Synaptic Plasticity

Synaptic Transmission

Neurodegenerative Disease Implications

Alzheimer's Disease

Parkinson's Disease

Other Neurodegenerative Conditions

Genetic Studies

GWAS Associations

Functional Genomics

Neuroimmune Functions

Microglial Interactions

Neuroinflammatory Signaling

Therapeutic Potential

Drug Development

Gene Therapy

Biomarker Potential

Animal Models

Knockout Models

Disease Models

Interaction Network

Receptor Interactions

Signaling Partners

Cross-Linking

Summary

References

External Links

💬 Discussion