ATG5 — Autophagy Related 5

ATG5 — Autophagy Related 5

Pathway Diagram

```mermaid
flowchart TD
ATG5["ATG5<br/>Autophagy-related 5"]

ULK1["ULK1<br/>Autophagy Initiator"]
AUTOPHAGY["Autophagy<br/>Pathway"]
EIF4EBP1["EIF4EBP1<br/>Translation<br/>Regulator"]

NEURODEGENERATION["Neurodegeneration"]
ALS["Amyotrophic Lateral<br/>Sclerosis (ALS)"]
PARKINSON["Parkinson's<br/>Disease"]
MS["Multiple<br/>Sclerosis"]

INFLAMMATION["Neuroinflammation"]
AGING["Cellular<br/>Aging"]
FERROPTOSIS["Ferroptosis<br/>(Iron-dependent<br/>Cell Death)"]

ACTB["ACTB<br/>Cytoskeleton"]
P2RY12["P2RY12<br/>Microglial<br/>Receptor"]
APOA1["APOA1<br/>Lipid Transport"]

STROKE["Stroke"]
THERAPY["Therapeutic<br/>Target"]

ULK1 -->|"activates"| ATG5
ATG5 -->|"participates_in"| AUTOPHAGY
ATG5 -->|"regulates"| EIF4EBP1

ATG5 -->|"inhibits"| NEURODEGENERATION
ATG5 -->|"inhibits"| ALS
ATG5 -->|"inhibits"| PARKINSON
ATG5 -->|"inhibits"| AGING
ATG5 -->|"inhibits"| INFLAMMATION

ATG5 -->|"contributes_to"| FERROPTOSIS
ATG5 -->|"associated_with"| MS

P2RY12 -->|"inhibits"| ATG5
ACTB -->|"interacts_with"| ATG5
APOA1 -->|"interacts_with"| ATG5

ATG5 -->|"therapeutic_target"| STROKE
STROKE --> THERAPY

style ATG5 fill:#006494
style AUTOPHAGY fill:#1b5e20
style ULK1 fill:#4a1a6b
style EIF4EBP1 fill:#4a1a6b
style NEURODEGENERATION fill:#ef5350
style ALS fill:#ef5350
style PARKINSON fill:#ef5350
style INFLAMMATION fill:#ef5350
style FERROPTOS

ATG5 — Autophagy Related 5

Pathway Diagram

Introduction

Atg5 — [Autophagy](/entities/autophagy) Related 5 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-gene"> [@atg2011]
<table> [@atg2012]
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">ATG5 — Autophagy Related 5</th></tr> [@atg2009]
<tr><td><strong>Gene Symbol</strong></td><td>ATG5</td></tr> [@atg2005]
<tr><td><strong>Full Name</strong></td><td>Autophagy Related 5</td></tr> [@atg2010a]
<tr><td><strong>Chromosome</strong></td><td>6q21</td></tr> [@atg2011a]
<tr><td><strong>NCBI Gene ID</strong></td><td>[9479](https://www.ncbi.nlm.nih.gov/gene/9479)</td></tr> [@atg2010b]
<tr><td><strong>OMIM</strong></td><td>604548</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000157640</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q9H1Y4](https://www.uniprot.org/uniprot/Q9H1Y4)</td></tr>
<tr><td><strong>Associated Diseases</strong></td><td>[Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), [Huntington's Disease](/diseases/huntingtons), [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)</td></tr>
<tr><td><strong>Protein</strong></td><td>[ATG5 Protein](/proteins/atg5-protein)</td></tr>
</table>
</div>

Overview

ATG5 (Autophagy Related 5) is a critical gene encoding a 278-amino acid protein essential for autophagosome formation in the macroautophagy pathway. Located on chromosome 6q21, ATG5 plays a fundamental role in cellular homeostasis through its involvement in the autophagy-lysosome system, which is crucial for clearing misfolded proteins, damaged organelles, and intracellular pathogens [1][2]. Dysregulation of ATG5-mediated autophagy is strongly implicated in the pathogenesis of neurodegenerative diseases including [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), Huntington's disease, and amyotrophic lateral sclerosis (ALS) [3][4].

Molecular Function

The Autophagy Machinery

ATG5 is a core component of the canonical autophagy pathway. It functions through:

Non-Autophagic Functions

Beyond canonical autophagy, ATG5 has several independent functions:

• [Apoptosis](/entities/apoptosis) regulation: ATG5 can be cleaved by calpains to generate a truncated fragment that translocates to mitochondria and promotes cytochrome c release, linking autophagy to apoptosis [9].
• Immune signaling: ATG5 regulates innate immune responses through interactions with mitochondrial antiviral signaling protein (MAVS) [10].
• DNA damage repair: ATG5 participates in DNA damage response pathways through interaction with p53 [11].

Expression and Regulation

Brain Expression

ATG5 is ubiquitously expressed in all brain cell types with highest expression in:

• [Neurons](/entities/neurons): Particularly in cerebral [[cortex](/brain-regions/cortex)](/brain-regions/cortex) pyramidal neurons and [[hippocampus](/brain-regions/hippocampus)](/brain-regions/hippocampus) CA1 neurons
• [Astrocytes](/entities/astrocytes): Constitutive expression for protein quality control
• [Microglia](/entities/microglia): Induction during cellular stress and neuroinflammation
• Oligodendrocytes: Essential for myelin maintenance

Transcriptional Regulation

ATG5 expression is regulated by:

• Transcription factors: [TFEB](/entities/tfeb) (transcription factor EB) and TFE3 drive ATG5 transcription during starvation [12].
• Epigenetic regulation: [DNA methylation](/entities/dna-methylation) of ATG5 promoter modulates expression in aging and AD [13].
• Post-transcriptional regulation: Various microRNAs (miR-101, miR-181a) target ATG5 mRNA [14].

Role in Neurodegenerative Diseases

Alzheimer's Disease

In Alzheimer's disease (AD), ATG5-mediated autophagy is critically impaired at multiple levels [15]:

• Autophagic vacuole accumulation: AD brains show dramatic accumulation of autophagic vacuoles in dystrophic neurites, reflecting impaired autophagosome-lysosome fusion [16].
• Amyloid-beta effects: Aβ42 oligomers inhibit autophagy through [mTOR](/entities/mtor) activation, while ATG5 deficiency exacerbates [Aβ](/proteins/amyloid-beta) toxicity [17].
• [Tau](/proteins/tau) pathology: Hyperphosphorylated tau disrupts autophagic-lysosomal pathway function; ATG5 reduction correlates with tau burden [18].
• Neuronal vulnerability: ATG5-deficient neurons show increased susceptibility to oxidative stress and mitochondrial dysfunction [19].

Parkinson's Disease

ATG5 and mitophagy are central to PD pathogenesis [20]:

• PINK1/Parkin pathway: ATG5 is required for Parkin-mediated mitophagy of damaged mitochondria [21].
• [Alpha-synuclein](/proteins/alpha-synuclein) clearance: ATG5-dependent autophagy facilitates clearance of [alpha-synuclein](/mechanisms/alpha-synuclein) aggregates; ATG5 deficiency promotes intracellular alpha-synuclein accumulation [22].
• Mitochondrial quality control: Dopaminergic neurons are particularly vulnerable to mitochondrial dysfunction; ATG5 loss accelerates neurodegeneration [23].
• [LRRK2](/entities/lrrk2) interaction: Mutant LRRK2 (G2019S) disrupts autophagic flux through ATG5 phosphorylation [24].

Huntington's Disease

In Huntington's disease (HD), mutant huntingtin (mHtt) protein impairs autophagy at multiple steps [25]:

• Autophagy initiation: mHtt sequesters ATG proteins including ATG5, disrupting autophagosome formation [26].
• Cargo recognition: Impaired p62 recruitment to autophagosomes reduces selective clearance of mutant huntingtin aggregates [27].
• Neuronal dysfunction: ATG5 overexpression in HD models reduces mutant huntingtin aggregation and improves motor function [28].

Amyotrophic Lateral Sclerosis

ATG5 dysfunction contributes to ALS through multiple mechanisms [29]:

• Stress granule clearance: ATG5 is required for clearance of stress granules containing mutant SOD1 and [TDP-43](/proteins/tdp-43) [30].
• RNA metabolism: Impaired autophagy leads to accumulation of toxic RNA-protein aggregates [31].
• Mitochondrial dysfunction: ATG5 deficiency exacerbates mitochondrial damage in motor neurons [32].
• [TDP-43](/mechanisms/tdp-43-proteinopathy) pathology: Autophagy-lysosomal pathway impairment contributes to TDP-43 aggregation, a hallmark of ALS [33].

Therapeutic Implications

Targeting ATG5 for Neuroprotection

• Rapamycin ([mTOR](/mechanisms/mtor-signaling-pathway) inhibitor) promotes ATG5-independent autophagy [34].
• Carbamazepine and trehalose activate TFEB to enhance ATG5 expression [35].
• Natural compounds (resveratrol, curcumin) modulate autophagy through AMPK activation [36].

• AAV-mediated ATG5 overexpression in mouse models shows neuroprotective effects [37].
• CRISPR activation of endogenous ATG5 promoter [38].

• ATG5-ATG12 interaction enhancers [39].
• Autophagy inducers targeting upstream regulators (AMPK activators) [40].

• Autophagy enhancement combined with amyloid/tau targeting [41].
• Synergistic effects with mitochondrial protectants [42].

Genetics

Common Polymorphisms

• ATG5 promoter polymorphisms (rs573775, rs510432) associated with AD risk in some populations [43].
• rs2245214 variant linked to ALS susceptibility [44].

Rare Variants

• Loss-of-function variants cause neonatal mitochondrial disease [45].
• Missense variants identified in patients with early-onset neurodegeneration [46].

Animal Models

Key experimental models include:

• Neuron-specific ATG5 knockout mice: Show neurodegeneration, accumulation of protein aggregates, and behavioral deficits [47].
• Conditional knockout models: Allow temporal deletion to assess adult-onset autophagy deficiency [48].
• Transgenic ATG5 overexpression: Protects against Aβ toxicity and improves cognitive function [49].

Key Publications

Background

The study of Atg5 — Autophagy Related 5 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.

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
• [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

References

Pathway Diagram

The following diagram shows the key molecular relationships involving ATG5 — Autophagy Related 5 discovered through SciDEX knowledge graph analysis:

GWAS Evidence

Genetic associations from the [NHGRI-EBI GWAS Catalog](https://www.ebi.ac.uk/gwas/) supporting gene-disease relationships:

• rs9497975 — HIV-1 control (p = 7.00e-08, n = 2,362 European ancestry cases) [PLoS Genet PMID:20041166](https://pubmed.ncbi.nlm.nih.gov/20041166/)
• rs212388 — Crohn's disease (p = 3.00e-14, n = Up to 12,924 European ancestry cases, up to 21,442 European ancestry controls ) [Nature PMID:23128233](https://pubmed.ncbi.nlm.nih.gov/23128233/)
• rs4654925 — Ulcerative colitis (p = 9e-22, n = 1,043 European ancestry cases, 1,703 European ancestry controls) [Nat Genet PMID:20228798](https://pubmed.ncbi.nlm.nih.gov/20228798/)
• rs2138852 — Mean platelet volume (p = 7e-28, n = 1,606 European ancestry individuals) [Am J Hum Genet PMID:19110211](https://pubmed.ncbi.nlm.nih.gov/19110211/)
• rs12049330 — Major depressive disorder (p = 6.00e-06, n = 1,020 European ancestry cases, 1,636 European ancestry controls) [Mol Psychiatry PMID:20125088](https://pubmed.ncbi.nlm.nih.gov/20125088/)
• rs1128334 — Systemic lupus erythematosus (p = 2.00e-11, n = 314 Chinese ancestry cases, 1,484 Chinese ancestry controls) [PLoS Genet PMID:20169177](https://pubmed.ncbi.nlm.nih.gov/20169177/)