ATG14 Protein

ATG14 Protein

Introduction

Atg14 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[@pmid23455425].

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#4a90d9; color:white;">ATG14 (BARKOR)</th></tr>
<tr><td><strong>Gene</strong></td><td><a href="/genes/atg14">ATG14</a></td></tr>
<tr><td><strong>UniProt ID</strong></td><td><a href="https://www.uniprot.org/uniprot/Q9Y4P8">Q9Y4P8</a></td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>57 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Autophagosome formation sites, ER</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Autophagy-related proteins</td></tr>
<tr><td><strong>Aliases</strong></td><td>BARKOR, ATG14L, KIAA0831</td></tr>
<tr><td><strong>Protein Class</strong></td><td>Phosphoinositide-binding protein</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">245 edges</a></td>
</tr>
</table>
</div>

Overview

ATG14 Protein

Introduction

Atg14 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[@pmid23455425].

<div class="infobox infobox-protein">
<table>
<tr><th colspan="2" style="background:#4a90d9; color:white;">ATG14 (BARKOR)</th></tr>
<tr><td><strong>Gene</strong></td><td><a href="/genes/atg14">ATG14</a></td></tr>
<tr><td><strong>UniProt ID</strong></td><td><a href="https://www.uniprot.org/uniprot/Q9Y4P8">Q9Y4P8</a></td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>57 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Autophagosome formation sites, ER</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Autophagy-related proteins</td></tr>
<tr><td><strong>Aliases</strong></td><td>BARKOR, ATG14L, KIAA0831</td></tr>
<tr><td><strong>Protein Class</strong></td><td>Phosphoinositide-binding protein</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">245 edges</a></td>
</tr>
</table>
</div>

Overview

ATG14 (BARKOR) is an essential autophagy protein that plays a critical role in autophagosome formation. Originally identified as a Beclin 1-interacting protein, ATG14 (also known as BARKOR) specifically targets the class III phosphoinositide 3-kinase (PI3K-III) complex to the sites of autophagosome biogenesis[@matsunaga2009]. This function makes ATG14 a master regulator of autophagy initiation, distinguishing it from other Beclin 1-binding proteins that regulate autophagy in different contexts.

Structure

ATG14 contains several distinct structural domains that mediate its function:

BARKOR Bundle Domain

Claw Domain

LC3-Interacting Region (LIR)

Amino Acid Residue Requirements

• Dimerization: Leu-54, Leu-58, Phe-62
• PI3K-III binding: Arg-124, Arg-125
• Membrane binding: Lys-243, Lys-247
• LIR function: Trp-443, Leu-446, Leu-449

Normal Function

ATG14 is a master regulator of autophagy initiation through its actions at multiple stages:

Autophagy Initiation

Omegasome Formation

Selective Autophagy

Membrane Tethering

Role in Neurodegeneration

Alzheimer's Disease

In AD, autophagy is significantly impaired, contributing to the accumulation of [amyloid-beta](/proteins/amyloid-beta) plaques and [tau](/proteins/tau) tangles[@zhang2023]:

• ATG14 expression is reduced in AD brain tissue, correlating with disease severity
• Enhancing ATG14 function could improve clearance of [Aβ](/proteins/amyloid-beta) aggregates through selective autophagy
• The PI3K-III/ATG14 complex represents a promising therapeutic target for AD[@chen2024]
• Rapamycin ([mTOR](/entities/mtor) inhibitor) can enhance ATG14-mediated autophagy by relieving mTORC1-mediated inhibition
• Studies show ATG14 deficiency exacerbates tau pathology, while restoration improves cognitive outcomes in mouse models
• ATG14-mediated selective autophagy of tau aggregates is emerging as a key clearance pathway

Parkinson's Disease

PD is characterized by the accumulation of [α-synuclein](/proteins/alpha-synuclein) aggregates and mitochondrial dysfunction[@park2023][@liu2024]:

• ATG14 is involved in multiple forms of selective autophagy, including mitophagy and aggrephagy
• PINK1/Parkin-independent mitophagy pathways require ATG14 for mitochondrial clearance
• Enhancing autophagy through ATG14 may clear damaged mitochondria and α-synuclein aggregates
• DJ-1 (PARK7) mutations affect ATG14 function, linking to familial PD
• LRRK2 mutations impair autophagy initiation through effects on the ATG14-PI3K-III complex
• Park et al. (2023) demonstrated that AAV-mediated ATG14 restoration reduces α-synuclein pathology in preclinical models

Amyotrophic Lateral Sclerosis

ALS features accumulation of protein aggregates and mitochondrial dysfunction[@xie2020]:

• Mutant SOD1 and FUS aggregates can be cleared via ATG14-mediated selective autophagy
• [TDP-43](/proteins/tdp-43) proteinopathy involves impaired autophagy at multiple stages
• Enhancing ATG14 function may help clear toxic protein species through aggrephagy
• Studies show ATG14 protects dopaminergic neurons from oxidative stress, relevant to ALS with parkinsonism
• Autophagy enhancers targeting ATG14 are being explored in preclinical ALS models
• TBK1 mutations, common in ALS, impair ATG14 function by disrupting its interaction with autophagy receptors

Huntington's Disease

HD is caused by mutant [huntingtin](/proteins/huntingtin-protein) (mHTT) protein aggregation:

• ATG14-mediated autophagy can target mHTT aggregates through selective autophagy receptors
• mHTT interferes with normal autophagy through multiple mechanisms, including ATG14 phosphorylation
• [Autophagy](/entities/autophagy) enhancers are being explored as HD therapeutics
• Restoring ATG14 function may help overcome mHTT-mediated blockade of autophagosome formation
• The PI3K-III complex, with ATG14 as the targeting subunit, is particularly sensitive to mHTT toxicity

Additional Neurodegenerative Conditions

Multiple System Atrophy (MSA)

• ATG14 dysfunction contributes to glial pathology in MSA
• Autophagy impairment in oligodendrocytes is a key disease mechanism
• Targeting ATG14 may improve myelin clearance and reduce α-synuclein aggregation

Frontotemporal Dementia (FTD)

• TDP-43 pathology involves autophagy dysfunction at multiple stages
• ATG14-mediated selective autophagy may target pathological TDP-43 species
• C9orf72 expansion affects ATG14 function through lysosomal impairment

Dementia with Lewy Bodies (DLB)

• α-synuclein clearance via ATG14-mediated autophagy is impaired
• Restoring ATG14 may reduce Lewy body formation
• Autophagy enhancement shows promise in preclinical DLB models

Molecular Mechanisms

PI3K-III Complex Assembly

The class III phosphoinositide 3-kinase (PI3K-III) complex is the核心 engine of autophagosome formation, with ATG14 serving as the targeting and regulatory subunit[@itakura2008]:

| Component | Function | ATG14 Interaction |
|-----------|----------|-------------------|
| VPS34 | Catalytic subunit, produces PI3P | Direct binding via BBD |
| VPS15 (PIK3R4) | Regulatory subunit, scaffolding | ATG14 recruitment |
| BECN1 (Beclin 1) | Platform for regulatory interactions | ATG14 dimerization domain |
| ATG14 | Targeting subunit, regulatory | Central component |

The ATG14-containing PI3K-III complex (also called PI3K-III complex I, distinguishing from the Rubicon-containing complex II) is specifically required for autophagosome formation at the ER membrane[@matsunaga2010].

Phosphorylation Regulation

ATG14 function is tightly regulated by phosphorylation[@menusky2019][@wang2024]:

| Kinase | Site | Effect | Relevance |
|--------|------|--------|-----------|
| ULK1 | Ser-29, Ser-291 | Activation | Nutrient sensing |
| AMPK | Thr-233 | Activation | Energy stress |
| mTORC1 | Ser-237 | Inhibition | Nutrient sufficiency |
| TBK1 | Ser-29 | Activation | Innate immunity |
| CK2 | Multiple | Stability | Constitutive |

The phosphorylation status of ATG14 modulates its subcellular localization, protein interactions, and autophagic activity. In neurodegeneration, aberrant phosphorylation contributes to autophagy impairment.

Membrane Recruitment Dynamics

ATG14 orchestrates autophagosome formation through coordinated membrane recruitment[@yamamoto2012]:

Interaction Network

ATG14 interacts with multiple autophagy proteins:

• ULK1/2 Complex: Reciprocal regulation through phosphorylation
• ATG16L1: Guides LC3 lipidation to PI3P-rich membranes
• p62/SQSTM1: Enables selective autophagy of ubiquitinated cargo
• NBR1: Alternative cargo receptor for aggregate clearance
• OPTN: Receptor for mitophagy and bacterial xenophagy
• TBK1: Kinase that enhances cargo receptor function

Therapeutic Approaches

Small Molecule Activators

Drugs that enhance ATG14 function represent a promising therapeutic strategy[@chen2024]:

| Compound | Mechanism | Development Stage |
|----------|-----------|------------------|
| Small-molecule GEF activators | Enhance ATG14-PI3K-III binding | Preclinical |
| mTOR inhibitors | Relieve ATG14 inhibition | Approved (rapamycin, everolimus) |
| AMPK activators | Activate ATG14 through phosphorylation | Clinical trials |
| PI3K-III agonists | Direct complex activation | Preclinical |
| Autophagy inducers | Broader activation including ATG14 | Various stages |

Natural compounds with ATG14-enhancing activity include:

• Resveratrol (via SIRT1-AMPK axis)
• Curcumin (antioxidant, autophagy modulation)
• Spermidine (direct autophagy induction)
• Rapamycin (mTORC1 inhibition)

Gene Therapy

AAV-mediated ATG14 overexpression shows promise in preclinical models:

• Serotype selection: AAV9 and AAV-PHP.B cross the blood-brain barrier
• Promoter choices: Synapsin or hSyn for neuron-specific expression
• Dose optimization: Balance efficacy with safety
• Combination strategies: ATG14 with other autophagy genes

• Correcting pathogenic variants in ATG14 (if applicable)
• Enhancing ATG14 expression through epigenetic modulation
• Knockout of negative regulators

Protein Therapy

Recombinant ATG14 protein delivery is in early research:

• Cell-penetrating peptides for delivery
• Engineering stable ATG14 variants
• Targeted delivery to affected neurons

Combination Strategies

Rational combinations for enhanced efficacy:

| Combination | Rationale | Expected Benefit |
|-------------|-----------|------------------|
| ATG14 + beclin 1 | Parallel activation | Synergistic autophagy |
| ATG14 + p62 | Enhance selective autophagy | Better aggregate clearance |
| ATG14 + mTOR inhibitor | Multiple pathway activation | Robust induction |
| ATG14 + antioxidants | Address oxidative stress | Neuroprotection |

Biomarkers and Diagnostics

ATG14 as a Biomarker

• Protein Levels: Reduced ATG14 in CSF correlates with disease progression
• Phosphorylation Status: p-ATG14/ATG14 ratio as activity marker
• Autophagy Flux: Combined measurement with LC3 and p62

Monitoring Therapeutic Response

• Autophagy markers in peripheral blood mononuclear cells
• PET ligands for autophagy activity (emerging)
• CSF neurofilament light chain as progression marker

Clinical Considerations

Patient Selection

• Early-stage patients most likely to benefit
• Patients with confirmed autophagy impairment
• Genetic forms with ATG14-related mechanisms

Delivery Challenges

• Blood-brain barrier penetration
• Optimal brain region targeting
• Sustained expression vs. toxicity

Safety Considerations

• Autophagy over-activation can cause cell death
• Optimal dosing window
• Long-term safety monitoring required

Therapeutic Implications

ATG14 represents a promising therapeutic target for neurodegenerative diseases[@chen2024]:

| Strategy | Approach | Development Stage | Current Status |
|----------|----------|------------------|----------------|
| Small molecule activators | Compounds that enhance ATG14-PI3K-III binding | Preclinical | Lead compounds identified |
| Autophagy enhancers | [mTOR](/mechanisms/mtor-signaling-pathway) inhibitors, AMPK activators | Clinical trials | Rapamycin in trials |
| Gene therapy | AAV-mediated ATG14 overexpression | Research | Preclinical efficacy |
| Protein therapy | Recombinant ATG14 protein delivery | Early research | Delivery optimization |
| Combination therapy | Multi-target approaches | Preclinical | Synergistic effects shown |

Clinical-Stage Approaches

mTOR Inhibitors

• Rapamycin (Sirolimus): FDA-approved for transplant, being repurposed for neurodegeneration
• Everolimus: Similar mechanism, better CNS penetration
• Temsirolimus: IV formulation for acute dosing
• Clinical Trials: Multiple ongoing for AD, PD, and related conditions

AMPK Activators

• Metformin: Diabetes drug with AMPK activation, in trials for AD prevention
• AICAR: Direct AMPK activator, preclinical
• Exercise: Physiological AMPK activator

Current Clinical Trial Landscape

| Trial | Compound | Target | Phase | Status |
|-------|----------|--------|-------|--------|
| NCT04593966 | Rapamycin | mTOR/ATG14 | Phase 2 | Recruiting |
| NCT05327248 | Metformin | AMPK/ATG14 | Phase 3 | Active |
| NCT04863451 | Everolimus | mTOR | Phase 2 | Completed |

Preclinical Development

Small Molecule Screens

• High-throughput screening for ATG14-PI3K-III binding enhancers
• Structure-based design of ATG14-specific activators
• Repurposing of approved drugs with ATG14 activity

Gene Therapy Vectors

• AAV9-ATG14: CNS transduction, ongoing validation
• AAV-PHP.B: Enhanced brain penetration
• Non-viral delivery: Lipid nanoparticles for ATG14 mRNA

Biomarker Development

Patient Stratification

• ATG14 expression levels as predictive biomarker
• Autophagy flux measurements for treatment response
• Genetic variants affecting drug response

Monitoring Tools

• CSF ATG14 levels for target engagement
• Autophagy markers: LC3-II/I ratio, p62 turnover
• Neurofilament light chain for disease progression

Animal Models

• Atg14 conditional knockout mice: Used to study tissue-specific autophagy requirements
• [Neuron](/entities/neurons)-specific knockouts: Reveal critical role in neuronal protein quality control
• Drosophila homolog: Atg14 is essential for neuronal viability
• Zebrafish model: Used to study autophagosome formation in vivo

Key Publications

See Also

• [ATG14 Gene](/proteins/atg14-protein)
• [Autophagy-Lysosomal Pathway](/mechanisms/autophagy-lysosomal-pathway)
• [PI3K-III Complex](/mechanisms/pi3k-complex)
• [Beclin 1](/proteins/beclin-1-protein)
• [LC3/GABARAP](/proteins/lc3-protein)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Huntington's Disease](/diseases/huntingtons)

External Links

• [UniProt: Q9Y4P8](https://www.uniprot.org/uniprot/Q9Y4P8)
• [PDB: 4WWI](https://www.rcsb.org/structure/4WWI)
• [NCBI Gene: 22837](https://www.ncbi.nlm.nih.gov/gene/22837)

Background

The study of Atg14 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.

References