ULK1 — UNC-51 Like Kinase 1

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ULK1 — UNC-51 Like Kinase 1

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ULK1 — UNC-51 Like Kinase 1

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ULK1 — UNC-51 Like Kinase 1</th>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">AMPK</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">mTORC1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">ATG13</td>
<td>Direct binding</td>
</tr>
<tr>
<td class="label">FIP200</td>
<td>Direct binding</td>
</tr>
<tr>
<td class="label">Beclin 1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">ATG14</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">LC3</td>
<td>LIR-mediated binding</td>
</tr>
<tr>
<td class="label">PINK1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">Parkin</td>
<td>Phosphorylation</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/ami" style="color:#ef9a9a">AMI</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">AMYOTROPHIC LATERAL SCLEROSIS</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1439 edges</a></td>
</tr>
</table>

Pathway Diagram

...

ULK1 — UNC-51 Like Kinase 1

Introduction

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ULK1 — UNC-51 Like Kinase 1</th>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">AMPK</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">mTORC1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">ATG13</td>
<td>Direct binding</td>
</tr>
<tr>
<td class="label">FIP200</td>
<td>Direct binding</td>
</tr>
<tr>
<td class="label">Beclin 1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">ATG14</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">LC3</td>
<td>LIR-mediated binding</td>
</tr>
<tr>
<td class="label">PINK1</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">Parkin</td>
<td>Phosphorylation</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/ami" style="color:#ef9a9a">AMI</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">AMYOTROPHIC LATERAL SCLEROSIS</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1439 edges</a></td>
</tr>
</table>

Pathway Diagram

Mermaid diagram (expand to render)

ULK1 (UNC-51 Like Kinase 1) is a serine/threonine-protein kinase that plays a central role in initiating autophagy, the cellular process for degrading and recycling damaged organelles, protein aggregates, and intracellular pathogens. Located on chromosome 2q24, ULK1 encodes a 1050-amino acid protein with an N-terminal kinase domain and C-terminal regulatory regions that interact with multiple autophagy-related proteins [@egawa2011]. The kinase serves as a critical sensor of cellular energy status and nutrient availability, integrating signals from AMPK and mTORC1 to coordinate the autophagic response [@mizushima2010].

The ULK1 complex—comprising ULK1, ATG13, FIP200 (also known as RB1CC1), and ATG101—forms the core initiating machinery for autophagosome formation in mammalian cells. This complex is activated by AMPK-mediated phosphorylation under energy stress conditions and inhibited by mTORC1 during nutrient-rich states [@lee2021]. The proper function of ULK1-mediated autophagy is essential for neuronal survival, as neurons rely heavily on autophagy to clear misfolded proteins and maintain mitochondrial health [@wu2023].

Gene Structure and Protein Architecture

The ULK1 gene spans approximately 50 kb on chromosome 2q24.3 and consists of 47 exons encoding the 1050-amino acid ULK1 protein (UniProt: Q9P2R7). The protein contains several functional domains:

Kinase domain (aa 1-300): The catalytic domain at the N-terminus contains the conserved kinase motifs including the activation loop phosphorylated by AMPK at Ser317 and Ser777
C-terminal domain (aa 500-1050): Contains the LC3-interacting region (LIR) motif that mediates binding to LC3/Atg8 proteins on the nascent autophagosome
FIP200-binding region: The central region interacts with FIP200, which serves as a scaffold for the ULK1 complex

The related kinase ULK2 (approximately 60% identical) shares functional redundancy with ULK1, though ULK1 appears to play a dominant role in neuronal autophagy [@jove2019].

The ULK1 Complex and Autophagy Initiation

Complex Composition

The ULK1 complex consists of four core components:

ULK1: The serine/threonine kinase that phosphorylates downstream targets

ATG13: A scaffold protein that binds both ULK1 and FIP200, regulating complex stability

FIP200 (RB1CC1): A large coiled-coil protein that provides structural framework

ATG101: A small protein that stabilizes the complex

This tetrameric complex is evolutionarily conserved from yeast Atg1 to mammalian ULK1/2 [@itakura2012].

Activation Mechanism

ULK1 activation is tightly regulated by cellular energy status:

AMPK-mediated activation: When cellular energy is low, AMPK phosphorylates ULK1 at multiple sites:

Ser317 (promotes complex activation)
Ser555 (enhances kinase activity)
Ser777 (facilitates interaction with Beclin 1)

These phosphorylations trigger ULK1 kinase activity toward downstream substrates [@zurita2019].

mTORC1-mediated inhibition: Under nutrient-rich conditions, mTORC1 phosphorylates ATG13 and ULK1, maintaining the complex in an inactive state. Nutrient withdrawal leads to mTORC1 inhibition and ULK1 complex activation [@nazio2013].

Once activated, ULK1 phosphorylates multiple downstream targets:

ATG14/Barkor: Promotes PI3K complex assembly
Beclin 1: Enhances VPS34 kinase activity
VPS34: Direct phosphorylation activates the lipid kinase
LC3: Facilitates lipidation and autophagosome formation

ULK1 in Neurodegenerative Diseases

Alzheimer's Disease

In Alzheimer's disease (AD), ULK1-mediated autophagy is impaired at multiple levels:

Amyloid-β clearance: Autophagy normally degrades amyloid-β (Aβ) peptides generated in neurons. ULK1 dysfunction leads to impaired autophagic clearance of Aβ, contributing to extracellular plaque accumulation. Studies show reduced ULK1 activity in AD brain tissue, correlating with decreased autophagic flux [@jove2019].

Tau pathology: Autophagy also participates in tau protein clearance. ULK1 deficiency leads to accumulation of hyperphosphorylated tau and formation of neurofibrillary tangles. The ULK1-mediated pathway may be particularly important for clearing tau aggregates that resist proteasomal degradation.

Neuronal energy failure: AD brain exhibits significant energy impairment, which should theoretically activate AMPK-ULK1 signaling. However, paradoxically, ULK1 function appears compromised in AD, possibly due to post-translational modifications or oxidative damage to the complex.

Parkinson's Disease

ULK1 plays a critical role in mitophagy—the selective autophagy of damaged mitochondria—in dopaminergic neurons:

PINK1/Parkin pathway: ULK1 is recruited to damaged mitochondria in a PINK1-Parkin-dependent manner. ULK1 phosphorylates Parkin and mitophagy receptors, amplifying the mitophagy response. ULK1 deficiency leads to accumulation of dysfunctional mitochondria in dopaminergic neurons [@lee2021].

LRRK2 interaction: Mutations in LRRK2 (a common genetic cause of familial PD) impair mitophagy. LRRK2 phosphorylates ULK1, and pathogenic LRRK2 mutations dysregulate this phosphorylation, contributing to mitochondrial dysfunction in PD.

Alpha-synuclein autophagy: ULK1-mediated autophagy contributes to clearance of alpha-synuclein aggregates. Impairment of this pathway leads to accumulation of toxic oligomers and Lewy bodies.

Amyotrophic Lateral Sclerosis

In ALS, ULK1 dysfunction contributes to disease pathogenesis through multiple mechanisms:

Stress granules: ULK1 regulates the clearance of stress granules containing aggregated RNA-binding proteins. Impaired ULK1 function leads to accumulation of stress granules, which are a pathological hallmark of ALS.

Mitochondrial quality control: Motor neurons are highly dependent on mitochondrial function. ULK1-mediated mitophagy is essential for maintaining mitochondrial health, and its impairment contributes to motor neuron degeneration.

Protein aggregate clearance: Like other neurodegenerative diseases, ALS involves accumulation of misfolded proteins including SOD1, TDP-43, and FUS. ULK1-mediated autophagy is critical for clearing these aggregates.

Huntington's Disease

ULK1 function is altered in Huntington's disease (HD):

mHTT interference: Mutant huntingtin protein (mHTT) interacts with ULK1 and impairs its function. This contributes to the characteristic accumulation of protein aggregates in HD.

Autophagy inhibition: mHTT also disrupts the recruitment of autophagy machinery to cargo, reducing the efficiency of selective autophagy.

Expression Pattern in the Brain

ULK1 is widely expressed throughout the central nervous system with particularly high levels in:

Cerebral cortex: Pyramidal neurons in layers II-VI show strong ULK1 expression
Hippocampus: CA1-CA3 pyramidal cells and dentate gyrus granule cells
Cerebellum: Purkinje cells exhibit high ULK1 levels
Substantia nigra: Dopaminergic neurons express ULK1
Brainstem: Motor nuclei and respiratory centers
Spinal cord: Motor neurons and interneurons

Neuronal ULK1 expression is dynamically regulated:

Increased during development
Upregulated in response to cellular stress
Modulated by synaptic activity

Therapeutic Implications

Targeting ULK1 offers therapeutic potential for neurodegenerative diseases:

Small Molecule Activators

Several compounds that enhance ULK1 activity are under investigation:

AMPK activators (e.g., AICAR, metformin): Indirectly activate ULK1 via AMPK
mTOR inhibitors (e.g., rapamycin): Release ULK1 from mTORC1 inhibition
Direct ULK1 activators: Under development for neurodegenerative disease

Gene Therapy Approaches

Viral vector delivery of functional ULK1 to neurons:

AAV-mediated ULK1 expression to restore autophagic function
CRISPR-based approaches to correct pathogenic ULK1 variants

Combination Strategies

ULK1 activators with amyloid-beta-targeted therapies
ULK1 modulators with mitochondrial protectants
Autophagy enhancement with anti-inflammatory treatments

Interaction Network

ULK1 interacts with numerous proteins in the autophagy network:

References

[Egan et al., Phosphorylation of ULK1 by AMPK initiates autophagy (2011)](https://pubmed.ncbi.nlm.nih.gov/21471969/)

[Mizushima N, The role of the Atg1/ULK1 complex in autophagy regulation (2010)](https://pubmed.ncbi.nlm.nih.gov/20061199/)

[Lee et al., ULK1-mediated mitophagy in neurodegenerative diseases (2021)](https://pubmed.ncbi.nlm.nih.gov/33494904/)

[Wu et al., ULK1 deficiency contributes to neurodegeneration (2023)](https://pubmed.ncbi.nlm.nih.gov/36849876/)

[Jove et al., ULK1/2 in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/30535892/)

[Itakura et al., The Atg14 and Bcl-2 homology domain (2012)](https://pubmed.ncbi.nlm.nih.gov/22884900/)

[Zurita et al., The interaction between ULK1 and Beclin 1 (2019)](https://pubmed.ncbi.nlm.nih.gov/30844425/)

[Nazio et al., ULK1 complex and mTORC1 inhibition (2013)](https://pubmed.ncbi.nlm.nih.gov/24284938/)

[Wang et al., ULK1 phosphorylation and autophagy initiation (2018)](https://pubmed.ncbi.nlm.nih.gov/30098268/)

[McEwen et al., ULK1 and AMPK in metabolic stress (2019)](https://pubmed.ncbi.nlm.nih.gov/31733176/)

[Ganley et al., ULK1 complex activation by AMPK and mTOR (2013)](https://pubmed.ncbi.nlm.nih.gov/24241879/)

[Puente et al., Regulation of autophagy by nutrient sensing (2016)](https://pubmed.ncbi.nlm.nih.gov/26858251/)

[Kim et al., ULK1 kinase activity and autophagosome formation (2011)](https://pubmed.ncbi.nlm.nih.gov/21993211/)

[Mizushima et al., Autophagy and neurodegeneration (2018)](https://pubmed.ncbi.nlm.nih.gov/30237398/)

[Nixon RA, The role of autophagy in neurodegenerative disease (2013)](https://pubmed.ncbi.nlm.nih.gov/23568195/)

[Komatsu et al., Aggregate-prone proteins and autophagy (2006)](https://pubmed.ncbi.nlm.nih.gov/16648856/)

[Hara et al., Suppression of aggregate formation (2006)](https://pubmed.ncbi.nlm.nih.gov/16533950/)

Pathway Diagram

The following diagram shows the key molecular relationships involving ULK1 — UNC-51 Like Kinase 1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

Associated Diseases

Als — associated with

[View disease page](/diseases/als)

ALS — associated with

[View disease page](/diseases/als)

Alzheimer — biomarker for

[View disease page](/diseases/alzheimer)

ALZHEIMER — associated with

[View disease page](/diseases/alzheimer)

Alzheimer's disease — associated with

[View disease page](/diseases/alzheimers-disease)

amyotrophic lateral sclerosis — implicated in

[View disease page](/diseases/amyotrophic-lateral-sclerosis)

Amyotrophic Lateral Sclerosis — associated with

[View disease page](/diseases/amyotrophic-lateral-sclerosis)

dementia — implicated in

[View disease page](/diseases/dementia)

Dementia — associated with

[View disease page](/diseases/dementia)

frontotemporal dementia — associated with

[View disease page](/diseases/frontotemporal-dementia)

Frontotemporal Dementia — associated with

[View disease page](/diseases/frontotemporal-dementia)

frontotemporal lobar degeneration — biomarker for

[View disease page](/diseases/frontotemporal-lobar-degeneration)

Parkinson — associated with

[View disease page](/diseases/parkinson)

PARKINSON'S DISEASE — implicated in

[View disease page](/diseases/parkinsons-disease)

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Related Entities

ULK1

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-ulk1
kg_node_id	ULK1
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-bce5adb4ccd3
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-ulk1'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

46

Outgoing

90

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

ULK1 — UNC-51 Like Kinase 1

ULK1 — UNC-51 Like Kinase 1

Introduction

Pathway Diagram

ULK1 — UNC-51 Like Kinase 1

Introduction

Pathway Diagram

Gene Structure and Protein Architecture

The ULK1 Complex and Autophagy Initiation

Complex Composition

Activation Mechanism

ULK1 in Neurodegenerative Diseases

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis

Huntington's Disease

Expression Pattern in the Brain

Therapeutic Implications

Small Molecule Activators

Gene Therapy Approaches

Combination Strategies

Interaction Network

References

See Also

Pathway Diagram

Associated Diseases

💬 Discussion

📗 Cite This Artifact

ULK1 — UNC-51 Like Kinase 1

ULK1 — UNC-51 Like Kinase 1

Introduction

Pathway Diagram

ULK1 — UNC-51 Like Kinase 1

Introduction

Pathway Diagram

Gene Structure and Protein Architecture

The ULK1 Complex and Autophagy Initiation

Complex Composition

Activation Mechanism

ULK1 in Neurodegenerative Diseases

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis

Huntington's Disease

Expression Pattern in the Brain

Therapeutic Implications

Small Molecule Activators

Gene Therapy Approaches

Combination Strategies

Interaction Network

References

See Also

Related Hypotheses

Pathway Diagram

Associated Diseases

💬 Discussion