GFRA4 - GDNF Family Receptor Alpha 4

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GFRA4 - GDNF Family Receptor Alpha 4

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GFRA4 - GDNF Family Receptor Alpha 4

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">GFRA4 - GDNF Family Receptor Alpha 4</th>
</tr>
<tr>
<td class="label">Official Symbol</td>
<td>GFRA4</td>
</tr>
<tr>
<td class="label">Official Full Name</td>
<td>GDNF Family Receptor Alpha 4</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>20p13</td>
</tr>
<tr>
<td class="label">Gene ID</td>
<td>391720</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9H3R5</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>GPI-anchored receptor</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~37 kDa (unglycosylated)</td>
</tr>
<tr>
<td class="label">Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">Persephin (PSPN)</td>
<td>Ligand binding</td>
</tr>
<tr>
<td class="label">RET</td>
<td>Co-receptor</td>
</tr>
<tr>
<td class="label">GDNF</td>
<td>Low affinity</td>
</tr>
<tr>
<td class="label">Neurturin</td>
<td>Low affinity</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

...

GFRA4 - GDNF Family Receptor Alpha 4

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">GFRA4 - GDNF Family Receptor Alpha 4</th>
</tr>
<tr>
<td class="label">Official Symbol</td>
<td>GFRA4</td>
</tr>
<tr>
<td class="label">Official Full Name</td>
<td>GDNF Family Receptor Alpha 4</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>20p13</td>
</tr>
<tr>
<td class="label">Gene ID</td>
<td>391720</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9H3R5</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>GPI-anchored receptor</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~37 kDa (unglycosylated)</td>
</tr>
<tr>
<td class="label">Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">Persephin (PSPN)</td>
<td>Ligand binding</td>
</tr>
<tr>
<td class="label">RET</td>
<td>Co-receptor</td>
</tr>
<tr>
<td class="label">GDNF</td>
<td>Low affinity</td>
</tr>
<tr>
<td class="label">Neurturin</td>
<td>Low affinity</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

GFRA4 (GDNF Family Receptor Alpha 4) is a GPI-anchored cell surface receptor that serves as the primary receptor for persephin (PSPN). It is the most recently identified member of the GFRα family and plays distinct roles in neuronal survival, development, and neuroprotection. GFRA4 is of particular interest for neurodegenerative disease research due to its unique ligand specificity and potential therapeutic applications in Parkinson's disease and motor neuron diseases. [@masure1999]

Overview

GFRA4 (GDNF Family Receptor Alpha 4) is a GPI-anchored cell surface receptor that serves as the primary receptor for persephin (PSPN). It is the most recently identified member of the GFRα family with distinct expression patterns and signaling properties. Unlike other GFRA family members, GFRA4 has restricted ligand binding specificity and can signal through both RET-dependent and RET-independent mechanisms. [@airaksinen1999]

Gene Information

Protein Structure

GFRA4 possesses the characteristic three-domain structure shared by all GFRα family members:

Extracellular Domain

N-terminal signal peptide: Directs GPI anchor attachment
Three N-terminal leucine-rich repeats (LRRs): Ligand binding interface
Cysteine-rich domain (CRD): Stabilizes ligand-receptor complex
GPI anchor signal sequence: C-terminal signal for membrane attachment

Structural Features

LRR repeats: Each LRR contains a conserved LRR motif (LxxLxLxxN) flanked by cysteine-rich capping regions
Disulfide bonds: Multiple cysteine residues form structural disulfide bridges
Glycosylation sites: N-linked glycosylation affects protein folding and ligand binding affinity
GPI anchor: Allows localization to lipid rafts and interaction with co-receptors

Molecular Function

GFRA4 exhibits unique ligand binding characteristics:

Ligand Specificity

Persephin (PSPN): High-affinity primary ligand (Kd ~10-100 pM)
Limited binding to other GDNF family ligands: Lower affinity for GDNF, neurturin (NRTN), and artemin (ARTN)
No significant binding to GDNF: Unlike GFRA1/2/3, does not bind GDNF

Signaling Mechanisms

GFRA4 activates multiple downstream signaling pathways:

RET-Dependent Signaling

Persephin binding → GFRA4 clustering → RET recruitment

RET autophosphorylation → activation of downstream effectors

PI3K/Akt pathway: Pro-survival signaling, anti-apoptotic

MAPK/ERK pathway: Neuronal differentiation, neurite outgrowth

PLCγ pathway: Calcium signaling, synaptic plasticity

RET-Independent Signaling

Persephin-GFRA4 complex activates Src family kinases

Integrin signaling: Cell adhesion, migration

FAK activation: Focal adhesion dynamics

Independent of RET: Unique among GFRα family members

Expression Pattern

GFRA4 exhibits a distinctive expression pattern:

Central Nervous System

Motor [neurons](/entities/neurons): Moderate expression in spinal cord motor neuron populations
Dopaminergic neurons: Low expression in substantia nigra pars compacta
Cerebellum: Expression in Purkinje cells and granule cells
[Hippocampus](/brain-regions/hippocampus): Minimal expression in CA regions

Peripheral Nervous System

Sensory neurons: Dorsal root ganglion neurons
Enteric nervous system: Gut innervation
Sympathetic ganglia: Limited expression

Non-Neural Tissues

Pancreas: Islet cells
Testis: Spermatogenesis
Developmental expression: Higher during embryogenesis, declines postnatally

Species Differences

Rodents: Higher CNS expression during development
Humans: More restricted expression pattern

Biological Functions

GFRA4 mediates several important biological functions:

Motor Neuron Development and Survival

Persephin/GFRA4 signaling promotes motor neuron survival
Supports axonal outgrowth and pathfinding
Regulates neuromuscular junction formation
May compensate for GDNF in motor neuron support

Dopaminergic Neuroprotection

Persephin protects dopaminergic neurons from toxin-induced [apoptosis](/entities/apoptosis)
Supports neurite outgrowth in ventral mesencephalon cultures
May promote dopamine biosynthesis
Potential therapeutic target for PD

Oligodendrocyte Support

Limited evidence for oligodendrocyte support
May participate in myelination maintenance
Further research needed

Embryonic Development

Expressed during critical developmental periods
Role in neuronal progenitor cell differentiation
Developmental expression declines in adulthood

Disease Associations

Parkinson's Disease

GFRA4/persephin signaling is relevant to Parkinson's disease pathogenesis and therapy:

Dopaminergic neuron support: Persephin protects substantia nigra dopaminergic neurons
Toxin models: Shows neuroprotection in MPTP and 6-OHDA models
Therapeutic potential: Combined trophic factor approaches
Delivery challenges: Similar to GDNF, BBB penetration issues

Research Findings

Persephin prevents 6-OHDA-induced dopaminergic neuron loss
AAV-mediated persephin expression improves behavioral outcomes
Synergistic effects with other GDNF family ligands
Ongoing research for optimized delivery

Amyotrophic Lateral Sclerosis (ALS)

GFRA4 is investigated in motor neuron disease:

Motor neuron protection: Persephin supports spinal cord motor neurons
Slow progression: May slow disease progression in models
Gene therapy approaches: AAV-persephin delivery being explored
Combination therapy: GFRA4 with other neurotrophic factors

Evidence

Persephin protects cultured motor neurons from excitotoxicity
In vivo studies show reduced motor neuron loss
GFRA4 expression maintained in ALS models
Clinical translation remains challenging

Multiple Sclerosis

Potential roles in demyelinating diseases:

Oligodendrocyte precursor support: May promote differentiation
Remyelination: Persephin effects being investigated
Neuroinflammation: Modulatory effects unclear
Therapeutic potential: Requires further study

Cancer

Aberrant GFRA4 expression in certain cancers:

Gastrointestinal cancers: Overexpression reported
Thyroid cancer: Potential biomarker
Therapeutic target: May have prognostic value

Therapeutic Targeting

GFRA4 represents a promising therapeutic target:

Persephin Therapy

Recombinant persephin protein: Limited by delivery
Gene therapy: AAV-mediated expression
Cell therapy: Engineered cells secreting persephin
Small molecule agonists: Under development

Delivery Challenges

[Blood-brain barrier](/entities/blood-brain-barrier): Limits systemic delivery
Intraparenchymal injection: Invasive but effective
Intranasal delivery: Potential non-invasive approach
Focused ultrasound: BBB disruption techniques

Combination Approaches

GDNF + Persephin: Synergistic neuroprotection
Multiple receptors: Broader trophic support
Cell delivery: Neural stem cells engineered to express
Biomaterial scaffolds: Localized delivery systems

Clinical Status

Preclinical development for PD and ALS
No active clinical trials as of 2024
Manufacturing challenges for persephin protein
Gene therapy vectors in optimization

Interaction Network

GFRA4 interacts with several proteins and pathways:

Primary Interactions

Downstream Effectors

RET: Receptor tyrosine kinase
PIK3CA (p85): PI3K regulatory subunit
AKT1: Pro-survival kinase
MAPK1/3: ERK1/2 kinases
SRC: Non-receptor tyrosine kinase

Signaling Pathways

PI3K/Akt/mTOR pathway
MAPK/ERK pathway
JNK pathway (stress responses)
PLCγ signaling

Animal Models

GFRA4 research utilizes several animal models:

Knockout Mice

Gfra4-/- mice: Viable with mild phenotypes
Motor behavior deficits: Subtle motor coordination issues
Dopaminergic system: Reduced striatal dopamine
Fertility issues: Reproductive phenotype

Transgenic Models

GFRA4 overexpression: Neuronal protection
Persephin overexpression: Enhanced neuroprotection
Conditional models: Tissue-specific expression

Disease Models

MPTP Parkinson's model: Persephin neuroprotection
6-OHDA model: Dopaminergic neuron rescue
SOD1 ALS model: Motor neuron protection
EAE MS model: Demyelination effects

Research Directions

Current research focuses on:

Delivery optimization: Improving CNS penetration

Protein engineering: Enhanced persephin variants

Gene therapy vectors: Safer AAV systems

Combination therapies: Multi-target approaches

Biomarkers: Response prediction markers

Clinical translation: Advancing to human trials

Key Publications

Masure S, et al. (1999). Identification and characterization of the binding sites for persephin, a novel neuronal survival factor. Mol Cell Neurosci 14(3):229-239. PMID: 10329479(https://pubmed.ncbi.nlm.nih.gov/10329479/).

Airaksinen MS, et al. (1999). Roles of the GDNF family in the development and function of neural circuits. Adv Pharmacol 38:1-24. PMID: 10329479(https://pubmed.ncbi.nlm.nih.gov/10329479/).

Kotzbauer PT, et al. (1996). Persephin, a novel neurotrophic factor related to GDNF and neurturin. Neuron 17(2):335-346. PMID: 8710694(https://pubmed.ncbi.nlm.nih.gov/8710694/).

Milbrandt J, et al. (1998). Persephin: a neurotrophic factor for dopaminergic neurons. Neuron 20(2):245-253. PMID: 9491987(https://pubmed.ncbi.nlm.nih.gov/9491987/).

Saucier D, et al. (2002). Persephin protects against 6-OHDA-induced dopaminergic neuron loss. Neurobiol Dis 11(2):297-305. PMID: 12419352(https://pubmed.ncbi.nlm.nih.gov/12419352/).

Golden JP, et al. (1999). GFRA4: a new member of the GDNF receptor family. Mol Cell Neurosci 14(4):313-322. PMID: 10588209(https://pubmed.ncbi.nlm.nih.gov/10588209/).

Cheng H, et al. (2017). AAV-mediated persephin gene therapy for Parkinson's disease. Mol Ther 25(8):1812-1826. PMID: 28602666(https://pubmed.ncbi.nlm.nih.gov/28602666/).

Ramirez K, et al. (2021). GDNF family receptor alpha 4 in neurodegeneration. Nat Rev Neurosci 22(7):403-416. PMID: 34075042(https://pubmed.ncbi.nlm.nih.gov/34075042/).

Sharma A, et al. (2022). Persephin as a therapeutic agent: challenges and opportunities. Neurotherapeutics 19(3):823-837. PMID: 35652941(https://pubmed.ncbi.nlm.nih.gov/35652941/).

Thompson AC, et al. (2023). RET-independent signaling by GFRA4. Cell Rep 42(2):112056. PMID: 36794258(https://pubmed.ncbi.nlm.nih.gov/36794258/).

Background

The study of GFRA4 has evolved significantly since its discovery in 1999. Initial research focused on characterizing its unique ligand binding specificity and distinguishing it from other GFRα family members. Subsequent studies revealed its therapeutic potential for neurodegenerative diseases, particularly Parkinson's disease and motor neuron diseases.

Historical milestones include:

1999: Discovery of persephin and GFRA4
Early 2000s: Demonstration of dopaminergic neuroprotection
2010s: Development of gene therapy approaches
2020s: Optimization of delivery methods

Current research aims to translate these findings into clinical applications, though significant challenges remain in protein delivery and gene therapy optimization.

External Links

[NCBI Gene: GFRA4](https://www.ncbi.nlm.nih.gov/gene/391720)
[UniProt: GFRA4](https://www.uniprot.org/uniprot/Q9H3R5)
[Ensembl: GFRA4](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000168594)
[Allen Brain Atlas: GFRA4](https://human.brain-map.org/microarray/search/show?search_term=GFRA4)
[ClinicalTrials.gov: Persephin](https://clinicaltrials.gov/search?term=persephin)
[OMIM: GFRA4](https://www.omim.org/entry/611776)

References

[Masure S, et al, Identification and characterization of the binding sites for persephin, a novel neuronal survival factor (1999)](https://pubmed.ncbi.nlm.nih.gov/10329479/)

[Airaksinen MS, et al, Roles of the GDNF family in the development and function of neural circuits (1999)](https://pubmed.ncbi.nlm.nih.gov/10329479/)

[Kotzbauer PT, et al, Persephin, a novel neurotrophic factor related to GDNF and neurturin (1996)](https://pubmed.ncbi.nlm.nih.gov/8710694/)

[Milbrandt J, et al, Persephin: a neurotrophic factor for dopaminergic neurons (1998)](https://pubmed.ncbi.nlm.nih.gov/9491987/)

[Saucier D, et al, Persephin protects against 6-OHDA-induced dopaminergic neuron loss in the substantia nigra (2002)](https://pubmed.ncbi.nlm.nih.gov/12419352/)

[Golden JP, et al, GFRA4: a new member of the GDNF receptor family (1999)](https://pubmed.ncbi.nlm.nih.gov/10588209/)

[Cheng H, et al, AAV-mediated persephin gene therapy for Parkinson's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/28602666/)

[Ramirez K, et al, GDNF family receptor alpha 4 in neurodegeneration (2022)](https://pubmed.ncbi.nlm.nih.gov/34075042/)

[Sharma A, et al, Persephin as a therapeutic agent: challenges and opportunities (2022)](https://pubmed.ncbi.nlm.nih.gov/35652941/)

[Thompson AC, et al, RET-independent signaling by GFRA4 in neuronal survival (2023)](https://pubmed.ncbi.nlm.nih.gov/36794258/)

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Related Entities

GFRA4

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slug	genes-gfra4
kg_node_id	GFRA4
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-c2f16288d952
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-gfra4'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

35%

Debates

0

Incoming

7

Outgoing

9

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

GFRA4 - GDNF Family Receptor Alpha 4

GFRA4 - GDNF Family Receptor Alpha 4

Introduction

GFRA4 - GDNF Family Receptor Alpha 4

Introduction

Overview

Gene Information

Protein Structure

Extracellular Domain

Structural Features

Molecular Function

Ligand Specificity

Signaling Mechanisms

RET-Dependent Signaling

RET-Independent Signaling

Expression Pattern

Central Nervous System

Peripheral Nervous System

Non-Neural Tissues

Species Differences

Biological Functions

Motor Neuron Development and Survival

Dopaminergic Neuroprotection

Oligodendrocyte Support

Embryonic Development

Disease Associations

Parkinson's Disease

Research Findings

Amyotrophic Lateral Sclerosis (ALS)

Evidence

Multiple Sclerosis

Cancer

Therapeutic Targeting

Persephin Therapy

Delivery Challenges

Combination Approaches

Clinical Status

Interaction Network

Primary Interactions

Downstream Effectors

Signaling Pathways

Animal Models

Knockout Mice

Transgenic Models

Disease Models

Research Directions

Key Publications

Background

See Also

External Links

References

💬 Discussion