```mermaid
flowchart TD
PEX3["PEX3<br/>Peroxisome Biogenesis<br/>Factor 3"]
SQSTM1["SQSTM1/p62<br/>Autophagy Receptor"]
LC3["LC3<br/>Autophagy Marker"]
RB1CC1["RB1CC1/FIP200<br/>Autophagy Initiation"]
PARKIN["PARKIN<br/>E3 Ubiquitin Ligase"]
SNCA["SNCA<br/>alpha-Synuclein"]
SNCAIP["SNCAIP<br/>Synphilin-1"]
MFN1["MFN1<br/>Mitofusin 1<br/>Mitochondrial Fusion"]
BCL2["BCL2<br/>Anti-apoptotic<br/>Protein"]
ERN1["ERN1/IRE1alpha<br/>ER Stress<br/>Sensor"]
FAM134B["FAM134B<br/>ER-phagy<br/>Receptor"]
ATM["ATM<br/>DNA Damage<br/>Response"]
STING1["STING1<br/>Innate Immunity<br/>Signaling"]
PD["Parkinson's<br/>Disease"]
AD["Alzheimer's<br/>Disease"]
ALS["Amyotrophic<br/>Lateral Sclerosis"]
FTD["Frontotemporal<br/>Dementia"]
PEX3 -->|"regulates"| SQSTM1
SQSTM1 -->|"binds"| LC3
PEX3 -->|"interacts"| RB1CC1
PEX3 -->|"interacts"| PARKIN
PARKIN -->|"ubiquitinates"| SNCA
PEX3 -->|"interacts"| SNCAIP
SNCA -->|"aggregates"| PD
PEX3 -->|"regulates"| MFN1
PEX3 -->|"interacts"| BCL2
MFN1 -->|"maintains"| BCL2
PEX3 -->|"responds_to"| ERN1
PEX3 -->|"interacts"| FAM134B
ERN1 -->|"activates"| FAM134B
PEX3 -->|"interacts"| ATM
PEX3 -->|"modulates"| STING1
ATM -->|"triggers"| STING1
SQSTM1 -->|"dysfunction"| AD
PARKIN -->|"mutations"| PD
ERN1 -->|"stress_response"| ALS
ATM -->|"damage_response"| FTD
style PEX3 fill:#006494
PEX3 encodes Peroxisome Biogenesis Factor 3, an essential peroxisomal membrane protein critical for peroxisome biogenesis, peroxisomal membrane protein (PMP) import, and peroxisome proliferation. PEX3 is one of the earliest factors required for peroxisome formation and serves as the primary docking site for the peroxisomal targeting signal type 2 (PTS2) receptor complex. Mutations in PEX3 cause severe peroxisome biogenesis disorders (PBDs) and are associated with impaired peroxisomal function in neurodegenerative diseases including Alzheimer's disease and Parkinson's disease[@muntau2000]. [@muntau2000]
<div class="infobox infobox-gene"> [@steinberg2015]
<div class="infobox-header">Gene Information</div> [@kou2021]
<div class="infobox-row"> [@cook2020]
<div class="infobox-label">Gene Symbol</div> [@fujiki2020]
<div class="infobox-value">PEX3</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Full Name</div>
<div class="infobox-value">Peroxisome Biogenesis Factor 3</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Chromosomal Location</div>
<div class="infobox-value">6q24.2</div>
</div>
<div class="infobox-row">
<div class="infobox-label">NCBI Gene ID</div>
<div class="infobox-value">[5679](https://www.ncbi.nlm.nih.gov/gene/5679)</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Ensembl ID</div>
<div class="infobox-value">ENSG00000034693</div>
</div>
<div class="infobox-row">
<div class="infobox-label">UniProt ID</div>
<div class="infobox-value">[Q9Y5Y8](https://www.uniprot.org/uniprot/Q9Y5Y8)</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Protein Aliases</div>
<div class="infobox-value">Pex3p, Peroxin-3</div>
</div>
<div class="infobox-row">
<div class="infobox-label">Associated Diseases</div>
<div class="infobox-value">Zellweger Syndrome, Peroxisome Biogenesis Disorders, Alzheimer's Disease, Parkinson's Disease</div>
</div>
</div>
PEX3 is a 476-amino acid peroxisomal membrane protein that plays a central role in peroxisome biogenesis. It is evolutionarily conserved from yeast to humans and is essential for life. PEX3 functions at multiple stages of peroxisome formation:
In [neurons](/entities/neurons), PEX3 is particularly important for maintaining peroxisomal function in regions with high metabolic demand and oxidative stress, making it relevant to neurodegenerative processes.
PEX3 contains several functional domains:
PEX3 is essential for peroxisome formation through several mechanisms:
| Pathway | Receptor | Cargo | PEX3 Role |
|---------|----------|-------|------------|
| PTS1 | PEX5 | Matrix proteins with SKL motif | Docking site |
| PTS2 | PEX7/PEX5/PEX18 | Matrix proteins with N-terminus | Indirect role |
| PMP import | PEX19 | Membrane proteins | Direct docking |
| Cell Type | Expression | Notes |
|-----------|------------|-------|
| Neurons | Moderate | Higher in metabolically active regions |
| [Astrocytes](/entities/astrocytes) | High | Peroxisomes abundant for lipid metabolism |
| [Microglia](/cell-types/microglia-neuroinflammation) | Moderate | [ROS](/entities/reactive-oxygen-species) handling, inflammation |
| Oligodendrocytes | High | Myelin lipid synthesis |
PEX3 is expressed throughout the brain with notable levels in:
PEX3 deficiency causes the most severe form of Zellweger syndrome[@steinberg2015]:
Clinical Features:
Association: Peroxisomal dysfunction in AD[@kou2021]
Mechanisms:
Association: Peroxisomal dysfunction in PD[@cook2020]
Mechanisms:
| Strategy | Approach | Status |
|----------|----------|--------|
| Gene therapy | AAV-PEX3 delivery | Preclinical |
| Small molecules | PEX3 expression modulators | Research |
| Plasmalogen supplementation | Restore membrane lipids | Clinical trials |
| Antioxidants | Reduce oxidative stress | Investigational |
Pex3−/− mice:
Neuron-specific Pex3 knockout:
| Mutation Type | Examples | Effect |
|---------------|----------|--------|
| Null | Frameshift, nonsense | Severe phenotype |
| Missense | R67Q, G170R | Variable severity |
| Splice site | IVS5+1G>A | Aberrant splicing |
The study of Pex3 Gene Peroxisome Biogenesis Factor 3 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.
The following diagram shows the key molecular relationships involving PEX3 Gene - Peroxisome Biogenesis Factor 3 discovered through SciDEX knowledge graph analysis: