| Gene |
[PINK1](/genes/pink1) |
| UniProt |
Q9BXM7 |
| PDB |
6EQI, 7JZZ |
| Mol. Weight |
63 kDa (full-length), 52 kDa (processed) |
| Localization |
Mitochondrial outer membrane |
| Family |
Serine/threonine kinase family |
| Diseases |
[Parkinson's Disease](/diseases/parkinsons-disease) |
PINK1 (PTEN-induced kinase 1) is a mitochondrial serine/threonine-protein kinase encoded by the PINK1 gene . It plays a critical role in mitochondrial quality control through the initiation of mitophagy, the selective autophagy of damaged mitochondria . PINK1 is one of the most important genes linked to early-onset Parkinson's disease (PD), with recessive loss-of-function mutations causing familial PD .
PINK1 was first identified as a gene upregulated by PTEN tumor suppressor, hence its name "PTEN-induced kinase 1" . It is highly expressed in neurons, particularly in the substantia nigra, and its dysfunction leads to mitochondrial impairment and dopaminergic neuron degeneration .
PINK1 contains several functional domains:
flowchart LR
subgraph PINK1_Domains
A["N-terminal MTS<br>Mitochondrial<br>Targeting"] --> B["Transmembrane<br>Domain"]
B --> C["Kinase<br>Domain"]
style C fill:#fff3e0,stroke:#333
end
click A "/proteins/pink1-protein" "PINK1 Structure"
click C "/proteins/pink1-protein" "PINK1 Kinase Domain"
A -->|"Import"| D["Healthy Mitochondria"]
click D "/mechanisms/mitochondrial-quality-control" "Mitochondrial QC"
D --> E["Cleavage<br>by PARL"]
E --> F["Degradation in<br>Cytosol"]
style D fill:#c8e6c9,stroke:#333
style F fill:#c8e6c9,stroke:#333
B -->|"Accumulation"| G["Damaged Mitochondria<br>Loss of Δψm"]
G --> H["PINK1 Autophosphorylation"]
H --> I["Parkin Recruitment"]
style G fill:#ffcdd2,stroke:#333
style I fill:#f3e5f5,stroke:#333
- N-terminal mitochondrial targeting sequence (MTS): Directs PINK1 to mitochondria
- Transmembrane domain: Anchors PINK1 to the mitochondrial outer membrane
- Kinase domain (C-terminal): Serine/threonine-protein kinase activity [^8]
- Ubiquitin-like domain: Binds ubiquitin and parkin [^9]
flowchart TD
A["Healthy Mitochondria<br/>Normal Membrane Potential"] --> B{"PINK1 Import"}
click A "/mechanisms/mitochondrial-quality-control" "Mitochondrial QC"
click B "/proteins/pink1-protein" "PINK1"
style A fill:#c8e6c9,stroke:#333
B -->|"Success"| C["Proteolytic Cleavage<br/>by PARL"]
C --> D["Degradation in<br/>Cytosol"]
style C fill:#c8e6c9,stroke:#333
style D fill:#c8e6c9,stroke:#333
B -->|"Failure"| E["Mitochondrial Damage<br/>Loss of Δψm"]
style E fill:#ffcdd2,stroke:#333
click E "/mechanisms/mitochondrial-dysfunction" "Mitochondrial Dysfunction"
E --> F["PINK1 Stabilization<br/>on Outer Membrane"]
F --> G["PINK1 Autophosphorylation"]
click F "/proteins/pink1-protein" "PINK1 Activation"
style F fill:#fff3e0,stroke:#333
G --> H["Phosphorylates Ubiquitin<br/>Ser65"]
G --> I["Phosphorylates Parkin<br/>Ser65"]
click H "/proteins/ubiquitin" "Ubiquitin"
click I "/proteins/parkin-protein" "Parkin"
style G fill:#f3e5f5,stroke:#333
style H fill:#f3e5f5,stroke:#333
style I fill:#f3e5f5,stroke:#333
H --> J["Parkin Activation"]
I --> J
J --> K["Ubiquitination of<br/>Mitochondrial Proteins"]
style J fill:#f3e5f5,stroke:#333
K --> L["Autophagy Receptor<br/>Recruitment<br/>p62, optineurin"]
click L "/mechanisms/selective-autophagy" "Selective Autophagy"
style L fill:#fff3e0,stroke:#333
L --> M["Autophagosome<br/>Formation"]
M --> N["Lysosomal<br/>Degradation"]
style M fill:#c8e6c9,stroke:#333
style N fill:#c8e6c9,stroke:#333
click M "/mechanisms/autophagosome-formation" "Autophagosome"
click N "/mechanisms/lysosomal-degradation" "Lysosome"
- Healthy mitochondria: PINK1 is imported and degraded [^10]
- Mitochondrial damage: Loss of membrane potential prevents import [^11]
- PINK1 accumulation: Stabilizes on outer membrane [^12]
- Parkin recruitment: Phosphorylates parkin and ubiquitin [13][14]
- Mitophagy initiation: Triggers selective autophagy
See also: PINK1/Parkin Mitophagy Pathway.
- Mitophagy initiation: Master regulator of damaged mitochondria clearance
- Mitochondrial dynamics: Regulates fission and fusion [15][16]
- Mitochondrial trafficking: Controls neuronal transport [^17]
- Energy metabolism: Affects ATP production [^18]
- Oxidative stress response: Activates antioxidant pathways [^19]
- Calcium homeostasis: Regulates mitochondrial calcium handling [^20]
- Anti-apoptotic function: Inhibits mitochondrial apoptosis pathway [^21]
PINK1 mutations cause autosomal recessive juvenile Parkinson's disease (PARK6) [^22]:
- Prevalence: ~1-9% of familial PD cases [^23]
- Age of onset: Typically 30-50 years (younger than sporadic PD) [^24]
- Clinical features: Tremor, bradykinesia, rigidity; good levodopa response [^25]
- Neuropathology: Loss of dopaminergic neurons in substantia nigra [^26]
PINK1 dysfunction leads to PD through several mechanisms [^27]:
- Failed mitophagy: Accumulation of damaged mitochondria [^28]
- Oxidative stress: Increased ROS production [^29]
- Energy deficit: Impaired ATP production [^30]
- Dopaminergic neuron vulnerability: Specific susceptibility of dopaminergic neurons [^31]
Multiple therapeutic approaches target PINK1 [^32]:
- Kinase activators: Small molecules that enhance PINK1 activity [^33]
- Mitophagy enhancers: Compounds that promote PINK1-Parkin pathway [^34]
- Mitochondrial protectors: Antioxidants and mitochondrial stabilizers [^35]
See also: PINK1/Parkin Activators.
- PINK1 overexpression: Viral vector delivery of wild-type PINK1 [^36]
- Parkin activation: Upstream targeting of the PINK1 pathway [^37]
¶ Clinical Trials and Drug Development
Several PINK1-targeted therapies are in development :
- PINK1 activators: Small molecule activators like utromagnetic compounds are being screened
- Kinase inhibitors: Though primarily for cancer, these provide structural insights
- Gene therapy vectors: AAV-PINK1 delivery showing promise in preclinical models
PINK1 mutation carriers show specific biomarkers :
- CSF biomarkers: Changes in tau and alpha-synuclein levels
- Imaging markers: Reduced dopamine transporter binding in PET scans
- Clinical markers: Early-onset tremor-dominant parkinsonism
Key PINK1 knockout models include :
- Mouse models: Motor deficits, mitochondrial dysfunction
- Drosophila models: Phototaxis defects, reduced lifespan
- iPSC models: Patient-derived dopaminergic neurons
Research priorities for PINK1 include :
- Structural biology: Cryo-EM structures of full-length PINK1
- Activation mechanisms: Understanding autophosphorylation regulation
- Therapeutic targeting: Developing brain-penetrant small molecules