PINK1 Protein

PINK1 Protein

Introduction

Pink1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

--- [@ref2004]
title: PINK1 Protein [@ref2009]
--- [@ref2010]

<div class="infobox infobox-protein"> [@ref2010a]
<h3>PINK1</h3> [@ref2006]
<table> [@referencesa]
<tr><th>Protein Name</th><td>PTEN-induced kinase 1</td></tr>
<tr><th>Gene</th><td><a href="/genes/PINK1">PINK1</a></td></tr>
<tr><th>UniProt</th><td><a href="https://www.uniprot.org/uniprot/Q9BXM7">Q9BXM7</a></td></tr>
<tr><th>PDB Structures</th><td>5W5R, 4Y94, 3M9L</td></tr>
<tr><th>Molecular Weight</th><td>63.1 kDa (581 aa)</td></tr>
<tr><th>Subcellular Localization</th><td>Mitochondrial inner membrane (OMM upon activation)</td></tr>
<tr><th>Protein Family</th><td>Ser/Thr protein kinases, PTEN family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/ali" style="color:#ef9a9a">ALI</a>, <a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</a>, <a href="/wiki/alzheimer's-disease" style="color:#ef9a9a">ALZHEIMER'S DISEASE</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2147 edges</a></td>
</tr>
</table>
</div>

Pathway / Mechanism Diagram

PINK1 Protein

Introduction

Pink1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

--- [@ref2004]
title: PINK1 Protein [@ref2009]
--- [@ref2010]

<div class="infobox infobox-protein"> [@ref2010a]
<h3>PINK1</h3> [@ref2006]
<table> [@referencesa]
<tr><th>Protein Name</th><td>PTEN-induced kinase 1</td></tr>
<tr><th>Gene</th><td><a href="/genes/PINK1">PINK1</a></td></tr>
<tr><th>UniProt</th><td><a href="https://www.uniprot.org/uniprot/Q9BXM7">Q9BXM7</a></td></tr>
<tr><th>PDB Structures</th><td>5W5R, 4Y94, 3M9L</td></tr>
<tr><th>Molecular Weight</th><td>63.1 kDa (581 aa)</td></tr>
<tr><th>Subcellular Localization</th><td>Mitochondrial inner membrane (OMM upon activation)</td></tr>
<tr><th>Protein Family</th><td>Ser/Thr protein kinases, PTEN family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/ali" style="color:#ef9a9a">ALI</a>, <a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</a>, <a href="/wiki/alzheimer's-disease" style="color:#ef9a9a">ALZHEIMER'S DISEASE</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">2147 edges</a></td>
</tr>
</table>
</div>

Pathway / Mechanism Diagram

Overview

--- title: PINK1 Protein --- <div class="infobox infobox-protein"> <h3>PINK1</h3> <table> <tr><th>Protein Name</th><td>PTEN-induced kinase 1</td></tr> <tr><th>Gene</th><td><a href="/genes/PINK1">PINK1</a></td></tr> <tr><th>UniProt</th><td><a href="https://www.

Structure

PINK1 is a mitochondrial serine/threonine-protein kinase:

• N-terminal mitochondrial targeting sequence (1-34): Positively charged amphipathic helix
• Transmembrane domain (77-110): Anchors to mitochondrial inner membrane
• Kinase domain (156-511): Ser/Thr protein kinase activity
• C-terminal regulatory region: Autoinhibitory domain

Normal Function

PINK1 is a mitochondrial damage sensor:

• Kinase activity: Phosphorylates ubiquitin and Parkin
• Mitophagy initiation: Activates Parkin recruitment to damaged mitochondria
• Mitochondrial quality control: Central to selective mitophagy
• Cell survival: Protects against mitochondrial toxins
• Metabolic regulation: Influences mitochondrial bioenergetics

Role in Disease

Autosomal Recessive Juvenile Parkinsonism (AR-JP)

• Mutations: >100 pathogenic variants
• Pathology:
• Loss of kinase activity
• Impaired mitophagy
• Accumulation of dysfunctional mitochondria
• Progressive dopaminergic neuron loss

Late-onset PD

• Heterozygous mutations may increase risk

Therapeutic Targeting

• Kinase activators: In development
• Gene therapy: AAV-PINK1 delivery
• Mitochondrial protectants: Upstream approaches

Key Publications

Background

The study of Pink1 Protein 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.

Brain Atlas Resources

PINK1 Protein can be explored through the following Allen Brain Atlas resources:

• [Allen Human Brain Atlas](https://human.brain-map.org/microarray/search/show?search_term=PINK1) — Search for PINK1 expression data across brain regions in the adult human brain.
• [Allen BrainSpan Atlas](https://www.brainspan.org/) — Explore developmental expression patterns across brain development.
• [Allen Cell Type Atlas](https://celltype.brain-map.org/) — Single-cell expression data for neuronal and glial cell types.
• [Allen Mouse Brain Atlas](https://mouse.brain-map.org/) — Mouse brain expression data for comparative studies.

Cross-Links

• See: PINK1 Gene - Gene encoding this protein
• See: Parkinson's disease - Disease context
• See: Parkin Protein - Partner in mitophagy
• See: mitophagy - Cellular mechanism

External Links

• [UniProt: Q9BXM7](https://www.uniprot.org/uniprot/Q9BXM7)
• [PDB: 5W5R](https://www.rcsb.org/structure/5W5R)## PINK1 in Parkinson's Disease

Pathogenic Mutations

Over 300 pathogenic mutations in PINK1 have been identified in patients with early-onset Parkinson's disease[@references]. Common pathogenic variants include:

• p.G309D: Destabilizes the kinase domain, reducing catalytic activity
• p.L347P: Disrupts mitochondrial targeting sequence
• p.W437X: Truncates the protein, eliminating kinase activity
• p.P399L: Impairs autophosphorylation
• p.R492X: Truncation mutation found in multiple families

PINK1-Parkin Pathway

The PINK1-Parkin pathway is the best-characterized mechanism of mitophagy:

[@ref2009]###
Targeting PINK1 kinase activity is a promising therapeutic strategy

• Clinical Significance

Genetics

• PINK1 mutations account for 1-2% of al- Autosomal recessive inheritance pattern
• Typical onset before age 50
• Good levodopa response
• Similar phenotype to PRKN mutations

Biomarkers

PINK1 activity in:

• Blood: Lymphocyte PINK1 levels correlate with disease progression
• CSF: Reduced PINK1 in PD patients
• Skin fibroblasts: PINK1 dysfunction in patient-derived cells

Models

• Knockout mice: Mild phenotype, age-related dopamine loss
• Drosophila: Robust model, recapitulates dopaminergic neuron loss
• iPSC models: Patient-derived neurons show mitophagy defects

Interactions and Network

Key Substrates

• Ubiquitin (Ub): Phosphorylation at Ser65 activates downstream signaling
• Parkin: Direct phosphorylation at Ser65 activates E3 ligase
• Miro1: Phosphorylation leads to mitochondrial arrest
• TFAM: Phosphorylation affects mitochondrial DNA transcription

Signaling Pathways

• MAPK pathway: PINK1 intersects with ERK and p38 signaling
• NF-κB pathway: PINK1 regulates inflammatory responses
• mTOR pathway: Negative regulator of mitophagy

Research Directions

Current Clinical Trials

Several trials are investigating PINK1-targeted interventions:

• Gene therapy approaches (AAV-PINK1)
• Kinase activator compounds
• Mitochondrial protective agents

Emerging Research

• Phospho-ubiquitin antibodies: Biomarkers for pathway activity
• Targeted protein degraders: Novel therapeutic modality
• Combination therapies: PINK1 activators with other mitochondrial targets

References

See Also

• [PINK1 Gene](/genes/PINK1)
• [Parkin Protein](/proteins/Parkin)
• Mitophagy in Parkinson's Disease
• [Mitochondrial Dynamics](/mechanisms/mitochondrial-dynamics)

• External Links

• [UniProt: Q9BXM7](https://www.rcsb.org/structure/5W5R)
• [GeneCards: PINK1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=PINK1)
• [OMIM: 605909](https://www.omim.org/entry/605909)

Biochemical Properties

Kinase Domain Structure

The kinase domain of PINK1 adopts a typical serine/threonine protein kinase fold with characteristic subdomains:

• Subdomain I (VAIK motif): ATP binding lysine residue essential for catalytic activity
• Subdomain VII (DFG motif): Asp-Phe-Gly motif critical for phosphotransfer
• Subdomain VIII (APE motif): Alanine-Proline-Glutamate sequence for substrate positioning

Substrate Specificity

PINK1 preferentially phosphorylates:

• Ubiquitin at Ser65: First identified physiological substrate
• Parkin at Ser65: Direct activation mechanism
• Miro1 at Ser17: Arrests mitochondrial transport
• TNF receptor-associated factor 6 (TRAF6): Regulates mitophagy

Regulation by Autophosphorylation

PINK1 autophosphorylation at multiple sites is essential for its activity:

• Ser402: Activation loop autophosphorylation
• Thr313: Stabilizes active conformation
• Ser228: Regulatory site

Post-Translational Modifications

Phosphorylation

PINK1 activity is tightly regulated by phosphorylation:

• Self-phosphorylation: Required for substrate recognition
• Phosphatase regulation: PP2A dephosphorylates PINK1 under basal conditions
• Oxidative stress: Oxidation of Cys-416 enhances activity

Ubiquitination

PINK1 itself is ubiquitinated by various E3 ligases:

• Parkin: Can ubiquitinate PINK1 under certain conditions
• MUL1: Alternative E3 ligase targeting PINK1
• USP30: Deubiquitinase that counteracts PINK1 ubiquitination

Protein-Protein Interactions

Mitochondrial Proteins

| Partner | Interaction | Functional Consequence |
|---------|-------------|----------------------|
| TOM Complex | Direct binding | Import channel for PINK1 |
| TIM23 Complex | Import machinery | Regulates PINK1 processing |
| VDAC1 | Phosphorylation target | Regulates metabolite flux |
| Miro1 | Phosphorylation | Mitochondrial arrest |
| MFN1/2 | Ubiquitination | Regulates fusion |

Cytosolic Proteins

| Partner | Interaction | Functional Consequence |
|---------|-------------|----------------------|
| Parkin | Phosphorylation | Activates E3 ligase |
| p62/SQSTM1 | Recruitment | Links to autophagy |
| LC3 | Binding | Autophagosome recruitment |
| HSP90 | Chaperone | Stabilizes PINK1 |

Clinical Trials and Therapeutic Development

Current Approaches

Several therapeutic strategies are being explored:

Challenges

• Blood-brain barrier: Delivery to CNS remains challenging
• Enzyme stability: PINK1 has relatively short half-life
• Selectivity: Avoiding off-target effects of kinase activators

Animal Models

Drosophila melanogaster

The Drosophila model recapitulates key features of PINK1 deficiency:

• Locomotor deficits: Climbing ability impaired
• Dopaminergic neuron loss: Selective vulnerability observed
• Mitochondrial morphology: Swollen, fragmented mitochondria
• Female sterility: Additional phenotype observed

Mouse Models

• Constitutive knockout: Mild phenotype with age-related changes
• Conditional knockouts: Brain-specific deletion shows more severe phenotype
• Knock-in models: Expressing patient mutations

iPSC Models

Patient-derived induced pluripotent stem cells:

• Dopaminergic neurons: Show impaired mitophagy
• Metabolic deficits: Altered mitochondrial function
• Alpha-synuclein aggregation: Increased aggregation propensity

Summary

PINK1 represents a critical node in mitochondrial quality control pathways. Its dysfunction leads to accumulation of damaged mitochondria and neuronal death characteristic of Parkinson's disease. Understanding PINK1 biology provides therapeutic opportunities for disease-modifying treatments.

References

Pathway Diagram

The following diagram shows the key molecular relationships involving PINK1 Protein discovered through SciDEX knowledge graph analysis: