PINK1 Protein

protein · SciDEX wiki

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.

--- 4(2004)2004 · PMID 15118497Open reference title: PINK1 Protein 5(2009)2009 · PMID 19966266Open reference --- 6(2010)2010 · PMID 20144137Open reference

7(2010)2010 · PMID 20100542Open reference

PINK1

8(2006)2006 · PMID 16672981Open reference 9</references>
Protein NamePTEN-induced kinase 1
GenePINK1
UniProtQ9BXM7
PDB Structures5W5R, 4Y94, 3M9L
Molecular Weight63.1 kDa (581 aa)
Subcellular LocalizationMitochondrial inner membrane (OMM upon activation)
Protein FamilySer/Thr protein kinases, PTEN family
Associated Diseases AD, ALI, ALS, ALZHEIMER, ALZHEIMER'S DISEASE
KG Connections 2147 edges

Pathway / Mechanism Diagram

graph TD
    A["Healthy Mitochondria"] --> B["PINK1 Imported and Degraded"]
    C["Damaged Mitochondria"] --> D["PINK1 Accumulates on OMM"]
    D --> E["PINK1 Autophosphorylation"]
    E --> F["Ubiquitin Phosphorylation"]
    F --> G["Parkin Recruitment"]
    G --> H["Polyubiquitin Chains on OMM"]
    H --> I["p62/OPTN Recognition"]
    I --> J["Autophagosome Engulfment"]
    J --> K["Mitophagy Complete"]
    L["PINK1 Mutations (PD)"] --> M["Failed Mitophagy"]
    M --> N["Damaged Mitochondria Persist"]
    N --> O["ROS Overproduction"]
    O --> P["Dopaminergic Neuron Death"]
    style K fill:#1b5e20,color:#e0e0e0
    style M fill:#ef5350,color:#e0e0e0
    style P fill:#ef5350,color:#e0e0e0

Overview

--- title: PINK1 Protein ---

PINK1

Protein NamePTEN-induced kinase 1
GenePINK1
UniProt<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

Under normal conditions, PINK1 is imported and degraded. Upon mitochondrial damage, it accumulates on the outer membrane.

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

  1. Valente EM, et al. (2004). “Hereditary early-onset Parkinson’s disease caused by mutations in PINK1.” Science. 1CitationPMID 15087508Open reference(https://pubmed.ncbi.nlm.nih.gov/15087508/)

  2. Narendra DP, et al. (2010). “PINK1 is selectively stabilized on impaired mitochondria.” Nat Cell Biol. 2CitationPMID 20159410Open reference(https://pubmed.ncbi.nlm.nih.gov/20159410/)

  3. Kane LA, et al. (2014). “PINK1 phosphorylates ubiquitin to activate Parkin.” J Cell Biol. 3CitationPMID 25437812Open reference(https://pubmed.ncbi.nlm.nih.gov/25437812/)

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:

  • See: PINK1 Gene - Gene encoding this protein

  • See: Parkinson’s disease - Disease context

  • See: Parkin Protein - Partner in mitophagy

  • See: mitophagy - Cellular mechanism

Pathogenic Mutations

Over 300 pathogenic mutations in PINK1 have been identified in patients with early-onset Parkinson’s disease10<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

These mutations impair the kinase’s ability to phosphorylate substrates and initiate mitophagy, leading to accumulation of dysfunctional mitochondria2CitationPMID 20159410Open reference0.

PINK1-Parkin Pathway

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

2CitationPMID 20159410Open reference1### 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

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

The activation loop contains several serine and threonine residues that undergo autophosphorylation, including Ser402, which is critical for full kinase activation2CitationPMID 20159410Open reference2.

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:

  1. Gene Therapy: AAV-mediated PINK1 delivery showing promise in preclinical models

  2. Small Molecule Activators: PINK1 kinase activators in early development

  3. Protein Replacement: Recombinant PINK1 delivery approaches

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

  1. PMID:15087508 PMID 15087508
  2. PMID:20159410 PMID 20159410
  3. PMID:25437812 PMID 25437812
  4. (2004) 1 Valente EM, et al 2004 · PMID 15118497
  5. (2009) 2 Narendra D, et al 2009 · PMID 19966266
  6. (2010) 3 Geisler S, et al 2010 · PMID 20144137
  7. (2010) 4 Matsuda N, et al 2010 · PMID 20100542
  8. (2006) 5 Clark IE, et al 2006 · PMID 16672981
  9. </references>
  10. <references>

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