PARKIN Gene

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PARKIN Gene

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">PARKIN Gene</th>
</tr>
<tr>
<td class="label">Domain</td>
<td>Amino Acids</td>
</tr>
<tr>
<td class="label">Ubl domain</td>
<td>1-76</td>
</tr>
<tr>
<td class="label">RING0</td>
<td>140-200</td>
</tr>
<tr>
<td class="label">RING1</td>
<td>212-255</td>
</tr>
<tr>
<td class="label">IBR</td>
<td>321-380</td>
</tr>
<tr>
<td class="label">RING2</td>
<td>418-465</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">PINK1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">UBC6, UBC7</td>
<td>E2 enzyme</td>
</tr>
<tr>
<td class="label">p62/SQSTM1</td>
<td>Binding</td>
</tr>
<tr>
<td class="label">OPTN</td>
<td>Binding</td>
</tr>
<tr>
<td class="label">NDP52</td>
<td>Binding</td>
</tr>
<tr>
<td class="label">VCP/p97</td>
<td>Binding</td>
</tr>
<tr>
<td class="label">BCL2</td>
<td>Binding</td>
</tr>
<tr>
<td class="label">CDC37</td>
<td>Binding</td>
</tr>
</table>

Gene Symbol: PARK2

Full Name: Parkin RBR E3 Ubiquitin Protein Ligase

Chromosomal Location: 6q26

NCBI Gene ID: [5071](https://www.ncbi.nlm.nih.gov/gene/5071)

OMIM: [600116](https://www.omim.org/entry/600116)

Ensembl ID: ENSG00000185358

UniProt ID: [O60260](https://www.uniprot.org/uniprot/O60260)

...

PARKIN Gene

Gene Symbol: PARK2

Full Name: Parkin RBR E3 Ubiquitin Protein Ligase

Chromosomal Location: 6q26

NCBI Gene ID: [5071](https://www.ncbi.nlm.nih.gov/gene/5071)

OMIM: [600116](https://www.omim.org/entry/600116)

Ensembl ID: ENSG00000185358

UniProt ID: [O60260](https://www.uniprot.org/uniprot/O60260)

Associated Diseases: [Parkinson's Disease](/diseases/parkinsons-disease), Autosomal Recessive Juvenile Parkinsonism

PARK2 (Parkin)

Overview

PARKIN (also known as PARK2, PRKN) is a critical gene in the study of neurodegenerative diseases, particularly [Parkinson's disease](/diseases/parkinsons-disease). This gene encodes the parkin protein, an E3 ubiquitin ligase essential for mitochondrial quality control through [mitophagy](/mechanisms/mitophagy). Mutations in PARKIN cause autosomal recessive juvenile parkinsonism (ARJP), characterized by early-onset Parkinson's disease with a typically slow but progressive course.

The PARKIN gene is located on chromosome 6q26 and spans approximately 1.4 Mb, making it one of the largest genes in the human genome. It contains 12 exons encoding a 465-amino acid protein. The gene was first linked to Parkinson's disease in 1998 when homozygous mutations were identified in families with autosomal recessive juvenile parkinsonism.

Normal Function

Parkin is a cytosolic E3 ubiquitin ligase essential for mitochondrial maintenance and quality control. Its normal functions encompass several critical cellular processes:

Mitochondrial Quality Control

Parkin plays a central role in maintaining mitochondrial homeostasis through multiple mechanisms:

Mitophagy induction: Parkin tags damaged mitochondria for autophagic degradation
Mitochondrial dynamics: Regulates mitochondrial fission and fusion processes
Protein degradation: Targets proteins for [ubiquitin-protease system](/mechanisms/ubiquitin-proteasome-system) degradation
Mitochondrial biogenesis: Coordinates with PGC-1α to regulate mitochondrial replication

The PINK1-Parkin Pathway

The PINK1-Parkin pathway is the primary mechanism for mitochondrial quality control. Here's how it works:

PINK1 stabilization: In healthy mitochondria, PINK1 (PTEN-induced kinase 1) is imported and degraded. In damaged mitochondria, PINK1 accumulates on the outer mitochondrial membrane.

PINK1 activation: Activated PINK1 phosphorylates ubiquitin at Ser65 and the Ubl domain of parkin at Ser65.

Parkin activation: Phospho-ubiquitin binds to parkin's RING0 domain, triggering a conformational change that activates its E3 ligase activity.

Ubiquitin chain formation: Active parkin ubiquitinates outer mitochondrial membrane proteins, forming Lys63-linked polyubiquitin chains.

[Autophagy](/entities/autophagy) receptor recruitment: p62/SQSTM1, OPTN, and NDP52 bind these ubiquitin chains and link mitochondria to the growing autophagosome.

Mitophagy execution: The LC3-coated autophagosome fuses with lysosomes, degrading the damaged mitochondrion.

Additional Cellular Functions

Beyond mitophagy, parkin performs several other essential functions:

Synaptic maintenance: Regulates synaptic vesicle proteins and neurotransmitter release
Cell survival: Protects [neurons](/entities/neurons) from apoptotic cell death through [NF-κB](/entities/nf-kb) signaling
DNA repair: Involved in mitochondrial DNA repair mechanisms
Iron metabolism: Regulates iron homeostasis through ferritin degradation

Protein Structure

The parkin protein (465 amino acids, ~52 kDa) contains multiple functional domains arranged in a specific architecture:

The RBR (RING-IBR-RING) architecture is unique among E3 ligases. The RING1 domain binds E2~Ub conjugates, while RING2 contains the catalytic cysteine that transfers ubiquitin to substrates. The IBR domain bridges these two RINGs and contributes to substrate recognition.

Disease Associations

Autosomal Recessive Juvenile Parkinsonism (ARJP)

PARKIN-linked ARJP (also called PARK2) accounts for approximately 50% of early-onset familial Parkinson's disease and about 10-20% of early-onset PD cases overall:

Age of onset: Typically before age 20, can be as early as 5-10 years
Clinical features: Tremor, bradykinesia, rigidity; typically bilateral symptoms
Disease course: Slow progression compared to sporadic PD
Levodopa response: Excellent and sustained levodopa responsiveness
Motor fluctuations: Early development of motor complications
Non-motor symptoms: Sleep disturbances, psychiatric symptoms common
Pathology: Loss of dopaminergic neurons in substantia nigra pars compacta

Parkinson's Disease

Beyond ARJP, PARKIN mutations contribute to Parkinson's disease in several ways:

Haploinsufficiency: Heterozygous mutations may increase PD risk
Modifier gene: PARKIN variants may modify age of onset
Synergistic effects: Interaction with other PD genes (LRRK2, SNCA)
Mitochondrial dysfunction: Common pathway in both familial and sporadic PD

Pathogenic Mechanisms

Mitophagy Defects

The primary pathogenic mechanism in PARKIN-linked PD is impaired mitophagy:

Failed mitochondrial clearance: Damaged mitochondria accumulate

ROS production: Dysfunctional mitochondria generate excess [reactive oxygen species](/entities/reactive-oxygen-species)

mtDNA mutations: Accumulation of mitochondrial DNA mutations

Energy crisis: Reduced ATP production affects neuronal function

Cell death: Progressive loss of dopaminergic neurons

Additional Mechanisms

α-Synuclein aggregation: Parkin failure leads to accumulation of α-synuclein
Lysosomal dysfunction: Impaired degradation of cellular debris
Endoplasmic reticulum stress: Disrupted protein folding
Calcium dysregulation: Mitochondrial calcium handling defects

Mutations and Variants

Over 200 pathogenic mutations in PARKIN have been identified, including:

Point mutations: Missense, nonsense, and splice-site mutations
Deletions: Exonic and whole-gene deletions (common)
Multiplications: Gene duplications and triplications

Common pathogenic variants include:

p.Cys212Arg (C212R)
p.Gly430Asp (G430D)
p.Arg275Trp (R275W)
p.Asp394Asn (D394N)
p.Lys211Asn (K211N)
Exon deletions (exons 3, 4, 5, 6)

Therapeutic Approaches

Gene Therapy

AAV-mediated PARKIN delivery: Viral vector delivery of functional PARKIN
CRISPR-based approaches: Gene editing to correct mutations
Protein replacement: Direct delivery of parkin protein

Small Molecule Activators

Mitophagy enhancers: USP30 inhibitors, NAD+ precursors
PINK1 activators: Compounds that stabilize PINK1
Parkin activators: Allosteric modulators of parkin activity

Symptomatic Treatments

Dopaminergic therapy: Levodopa, dopamine agonists
MAO-B inhibitors: Selegiline, rasagiline
COMT inhibitors: Entacapone, tolcapone

Neuroprotective Strategies

Antioxidants: CoQ10, MitoQ, NAC
Mitochondrial supplements: Creatine, L-carnitine
Anti-apoptotic agents: Bcl-2 family modulators

Animal Models

Several animal models have been developed to study PARKIN function:

Knockout mice: Show subtle mitochondrial defects but not overt neurodegeneration
Drosophila models: parkin null flies exhibit mitochondrial pathology and reduced lifespan
Induced models: MPTP/rotenone models reproduce aspects of parkinsonism

Interactions and Network

Parkin interacts with numerous proteins forming a complex network:

Research Directions

Current research focuses on:

Understanding parkin activation: Structural studies of the activation mechanism

Identifying substrates: Comprehensive mapping of parkin ubiquitination targets

Therapeutic screening: High-throughput screens for parkin activators

Biomarkers: Developing markers for early detection and monitoring

Gene therapy optimization: Improving delivery and expression

Allen Brain Atlas

[Human Brain Map - PARKIN Expression](https://human.brain-map.org/microarray/search/show?search_term=PRKN)
[Human Brain Map - Parkin Expression](https://human.brain-map.org/microarray/search/show?search_term=parkin)
[Allen Cell Type Atlas](https://celltypes.brain-map.org/)
[BrainSpan Transcriptome Atlas](https://brainspan.org/)
[Allen Mouse Brain Atlas](https://mouse.brain-map.org/)

References

[Kitada T, et al., Mutations in the parkin gene cause autosomal recessive juvenile parkinsonism. Nature. 1998;392(6676):605-608 (1998)](https://doi.org/10.1038/33416)

[Shimura H, et al., Ubiquitination of a new form of alpha-synuclein by parkin. Nature. 2000;406(6796):863-867 (2000)](https://doi.org/10.1038/35022584)

[Narendra D, et al., p62/SQSTM1 is required for parkin-induced mitochondrial clustering but not mitophagy. Autophagy. 2008;4(6):706-708 (2008)](https://doi.org/10.4161/auto.6386)

[Pickrell AM, et al., Endogenous Parkin Preserves Mitochondrial Function during Cellular Stress. Neuron. 2015;88(2):286-299 (2015)](https://doi.org/10.1016/j.neuron.2015.09.022)

[Kane LA, et al., PINK1 phosphorylates ubiquitin to activate parkin E3 ubiquitin ligase activity. J Cell Biol. 2014;205(2):143-153 (2014)](https://doi.org/10.1083/jcb.201402104)

[Kazlauskaite A, et al., Phosphorylation of parkin at Serine65 is essential for its activation in vitro. FEBS Lett. 2014;588(17):2825-2832 (2014)](https://doi.org/10.1016/j.febslet.2014.06.014)

[Matsuda N, et al., Phosphorylation of p62/SQSTM1 at Ser405 drives aggregate formation and localization in autophagy-deficient neurons. J Biol Chem. 2015;290(30):18227-18240 (2015)](https://doi.org/10.1074/jbc.M115.665156)

[Scarffe LA, et al., Parkin and PINK1: IP3Ribly close. Cell. 2014;159(5):1025-1027 (2014)](https://doi.org/10.1016/j.cell.2014.11.003)

[Gandhi S, et al., PINK1 protein in normal human brain. Brain Res. 2009;1272:48-54 (2009)](https://doi.org/10.1016/j.brainres.2009.03.041)

[Unknown, Cookson MR. Parkin and the molecular pathways of Parkinson's disease. Neuron. 2010;68(2):211-214 (2010)](https://doi.org/10.1016/j.neuron.2010.10.015)

[Zhang C, et al., Neuroprotective effects of parkin on dopaminergic neurons: From molecular mechanisms to therapeutic strategies. Free Radic Biol Med. 2021;166:86-98 (2021)](https://doi.org/10.1016/j.freeradbiomed.2021.02.019)

[Lück CB, et al., The diverse functions and mechanisms of parkin in cellular signaling. Cell Signal. 2021;85:110073 (2021)](https://doi.org/10.1016/j.cellsig.2021.110073)

Pathway Diagram

The following diagram shows key molecular relationships for PARKIN Gene based on knowledge graph edges:

Mermaid diagram (expand to render)

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

[Microbial Inflammasome Priming Prevention](/hypothesis/h-e7e1f943) — 0.76 · Target: NLRP3, CASP1, IL1B, PYCARD
[Targeted Butyrate Supplementation for Microglial Phenotype Modulation](/hypothesis/h-3d545f4e) — 0.72 · Target: GPR109A
[Vagal Afferent Microbial Signal Modulation](/hypothesis/h-ee1df336) — 0.71 · Target: GLP1R, BDNF
[Selective TLR4 Modulation to Prevent Gut-Derived Neuroinflammatory Priming](/hypothesis/h-f3fb3b91) — 0.67 · Target: TLR4
[Enhancing Vagal Cholinergic Signaling to Restore Gut-Brain Anti-Inflammatory Communication](/hypothesis/h-a4e259e0) — 0.65 · Target: CHRNA7
[Targeting Bacterial Curli Fibrils to Prevent α-Synuclein Cross-Seeding](/hypothesis/h-8b7727c1) — 0.64 · Target: CSGA
[Gut Barrier Permeability-α-Synuclein Axis Modulation](/hypothesis/h-6c83282d) — 0.60 · Target: CLDN1, OCLN, ZO1, MLCK
[Microbial Metabolite-Mediated α-Synuclein Disaggregation](/hypothesis/h-74777459) — 0.57 · Target: SNCA, HSPA1A, DNMT1

Related Analyses:

[What are the mechanisms by which gut microbiome dysbiosis influences Parkinson's disease pathogenesi](/analysis/SDA-2026-04-01-gap-20260401-225149) 🔄
[What are the mechanisms by which gut microbiome dysbiosis influences Parkinson's disease pathogenesi](/analysis/SDA-2026-04-01-gap-20260401-225155) 🔄

Pathway Diagram

The following diagram shows the key molecular relationships involving PARKIN Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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PARKIN Gene

PARKIN Gene

PARKIN Gene

PARK2 (Parkin)

Overview

Normal Function

Mitochondrial Quality Control

The PINK1-Parkin Pathway

Additional Cellular Functions

Protein Structure

Disease Associations

Autosomal Recessive Juvenile Parkinsonism (ARJP)

Parkinson's Disease

Pathogenic Mechanisms

Mitophagy Defects

Additional Mechanisms

Mutations and Variants

Therapeutic Approaches

Gene Therapy

Small Molecule Activators

Symptomatic Treatments

Neuroprotective Strategies

Animal Models

Interactions and Network

Research Directions

See Also

Allen Brain Atlas

References

Pathway Diagram

Related Hypotheses

Pathway Diagram