| DJ-1 (PARK7) — Protein Deglutathionylase |
|---|
| Gene | [PARK7](/genes/park7) |
| UniProt ID | [Q99497](https://www.uniprot.org/uniprot/Q99497) |
| PDB Structures | 1O62, 1O63, 2RK3, 5D7E |
| Molecular Weight | 20,898 Da (189 aa) |
| Subcellular Localization | Cytoplasm, Nucleus, Mitochondria |
| Protein Family | DJ-1/PfpI family |
| EC Number | 3.5.1.124 |
DJ-1 (PARK7) is a multifunctional protein encoded by the PARK7 gene, named after the PARK7 locus linked to Parkinson's disease. Originally discovered as an oncogene, DJ-1 has emerged as a critical neuroprotective protein with diverse functions in cellular stress response.
DJ-1 adopts a conserved α/β fold characteristic of the DJ-1/PfpI family:
- α/β Sandwich: 8 β-strands surrounded by 6 α-helices
- Catalytic Cysteine: Cysteine 106 (C106) — critical for enzymatic activity
- RNA-Binding Domain: C-terminal region involved in RNA binding
- Dimerization Interface: Forms functional homodimers
- Oxidation: C106 oxidized to sulfinic/sulfonic acid
- Phosphorylation: Multiple phosphorylation sites (S66, Y127)
- Sumoylation: SUMO conjugation at K6
DJ-1 participates in multiple cellular protective pathways:
DJ-1 functions as a:
- Deglutathionylase: Removes GSH adducts from proteins
- ROS Scavenger: Direct antioxidant activity
- Mitochondrial Protector: Maintains mitochondrial integrity
- p53 Modulation: Represses p53-mediated apoptosis
- Nrf2 Activation: Binds to Keap1, releasing Nrf2 for antioxidant response
- PI3K/Akt Signaling: Enhances cell survival
- Complex I Activity: Maintains mitochondrial respiratory chain
- Mitophagy: Regulates clearance of damaged mitochondria
- Calcium Homeostasis: Modulates mitochondrial calcium signaling
- mRNA Stability: Binds to 3'UTR of target mRNAs
- tRNA Processing: Associated with tRNA processing complexes
DJ-1 loss-of-function contributes to PD through:
-
Increased Oxidative Stress
- Impaired antioxidant response
- Elevated ROS accumulation
-
Mitochondrial Dysfunction
- Reduced Complex I activity
- Impaired mitophagy
-
α-Synuclein Toxicity
- Failed protection against α-synuclein aggregation
- Altered autophagy-lysosome pathway
-
Dopaminergic Neuron Vulnerability
- Enhanced sensitivity to mitochondrial toxins
- Impaired stress response
| Mutation |
Effect |
Phenotype |
| L166P |
Misfolding, rapid degradation |
Severe PD |
| M26I |
Partial loss of function |
Early-onset PD |
| E64D |
Variable |
Typical PD |
| A104T |
Reduced activity |
Risk factor |
DJ-1 represents a promising therapeutic target:
- Small Molecule Activators: Enhance DJ-1 activity
- Stabilization: Prevent misfolding and degradation
- Gene Therapy: Viral delivery of functional DJ-1
- Protein Replacement: Exogenous DJ-1 administration
| Tissue |
Expression |
| Brain (substantia nigra) |
Highest |
| Heart |
High |
| Liver |
Moderate |
| Kidney |
Moderate |
| Pancreas |
Low |
DJ-1 interacts with numerous proteins:
- Parkin — E3 ubiquitin ligase involved in mitophagy
- PINK1 — Kinase that phosphorylates Parkin
- DJ-1/PARK7 — Homodimer formation
- Hsp70 — Molecular chaperone
- Keap1 — Nrf2 regulator
- Developing DJ-1 activity assays
- Identifying brain-penetrant small molecule activators
- Understanding oxidation-dependent regulation
- Clinical biomarker development