ULK4 Gene

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ULK4 Gene

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ULK4 Gene

Overview

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ULK4 Gene

Overview

Mermaid diagram (expand to render)

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">ULK4 Gene</th>
</tr>
<tr>
<td class="label">Feature</td>
<td>Details</td>
</tr>
<tr>
<td class="label">Molecular weight</td>
<td>~170 kDa</td>
</tr>
<tr>
<td class="label">Structure</td>
<td>Kinase domain (N-terminus); coiled-coil domains (C-terminus)</td>
</tr>
<tr>
<td class="label">Domains</td>
<td>Serine/threonine kinase domain; regulatory domain</td>
</tr>
<tr>
<td class="label">Subcellular</td>
<td>Cytoplasmic; localizes to axons and synapses</td>
</tr>
<tr>
<td class="label">Homologs</td>
<td>ULK1, ULK2, ULK3 (functionally related)</td>
</tr>
<tr>
<td class="label">Component</td>
<td>Role</td>
</tr>
<tr>
<td class="label">ULK1/2</td>
<td>Catalytic subunits</td>
</tr>
<tr>
<td class="label">ATG13</td>
<td>Scaffold protein</td>
</tr>
<tr>
<td class="label">FIP200</td>
<td>Substrate recruitment</td>
</tr>
<tr>
<td class="label">ATG101</td>
<td>Complex stabilization</td>
</tr>
<tr>
<td class="label">Model</td>
<td>ULK4 Role</td>
</tr>
<tr>
<td class="label">AD models</td>
<td>Reduced ULK4</td>
</tr>
<tr>
<td class="label">PD models</td>
<td>Impaired mitophagy</td>
</tr>
<tr>
<td class="label">Schizophrenia</td>
<td>Loss-of-function</td>
</tr>
<tr>
<td class="label">Model</td>
<td>Application</td>
</tr>
<tr>
<td class="label">ULK4 KO</td>
<td>Loss-of-function</td>
</tr>
<tr>
<td class="label">ULK4 flox</td>
<td>Conditional KO</td>
</tr>
<tr>
<td class="label">ULK4 reporter</td>
<td>Expression mapping</td>
</tr>
<tr>
<td class="label">Species</td>
<td>ULK4 Homolog</td>
</tr>
<tr>
<td class="label">Human</td>
<td>ULK4</td>
</tr>
<tr>
<td class="label">Mouse</td>
<td>Ulk4</td>
</tr>
<tr>
<td class="label">Zebrafish</td>
<td>ulk4a/b</td>
</tr>
<tr>
<td class="label">Drosophila</td>
<td>none</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

ULK4 (Unc-51 Like Kinase 4) is a serine/threonine kinase encoded by the ULK4 gene on chromosome 3p21.2. ULK4 is part of the ULK family (ULK1, ULK2, ULK3, ULK4) which are key initiators of [autophagy](/entities/autophagy). ULK4 is expressed in the brain and has been implicated in neurodevelopment, axon guidance, and neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and schizophrenia.

Function

The ULK4 gene encodes a serine/threonine kinase with the following functions: [@mizushima2022]

Autophagy initiation: Part of the ULK1/2/3/4 kinase complex that initiates autophagosome formation
Axon guidance: Regulates cytoskeletal dynamics important for neuronal axon guidance and branching
Neurodevelopment: Essential for proper brain development; ULK4 variants associated with neurodevelopmental disorders
Stress response: Activated during cellular stress to initiate protective autophagy
mTORC1 regulation: Acts downstream of mTORC1; mTORC1 inhibition activates ULK4 kinase activity
Synaptic function: Regulates synaptic vesicle trafficking and neurotransmitter release

Protein Structure

Disease Associations

Alzheimer's Disease (AD)

Role: ULK4-mediated autophagy is important for clearing [amyloid-beta](/proteins/amyloid-beta) and [tau](/proteins/tau) aggregates
Evidence: ULK4 polymorphisms associated with AD risk in genome-wide studies
Therapeutic targeting: ULK4 activators may enhance autophagy and reduce AD pathology

Parkinson's Disease (PD)

Role: Critical for mitophagy of damaged dopaminergic [neurons](/entities/neurons)
Evidence: ULK4 expression reduced in PD brain; ULK4 variants associated with PD risk
Therapeutic targeting: Enhancing ULK4 activity may protect dopaminergic neurons

Schizophrenia

Role: ULK4 is one of the most penetrant genes for schizophrenia risk
Evidence: Rare ULK4 loss-of-function variants cause schizophrenia; brain development deficits
Mechanism: Impaired neurodevelopment and synaptic formation

Other Associations

Amyotrophic Lateral Sclerosis (ALS): ULK4 variants found in some cases
Intellectual disability: ULK4 deficiency causes mild to moderate intellectual disability
Rare diseases: ULK4 deficiency syndrome with developmental delay, speech impairment

Molecular Mechanisms

Kinase Activity

ULK4 possesses serine/threonine kinase activity:

Autophosphorylation: ULK4 can phosphorylate itself
Substrate specificity: Prefers serine/threonine over tyrosine
Activity regulation: Low basal activity, activated by stress
Domain structure: Kinase domain at N-terminus

Autophagy Initiation

ULK4 functions in the autophagy initiation complex:

Neuronal Functions

ULK4-specific neuronal roles:

Axon guidance: Regulates cytoskeletal dynamics
Synapse formation: Essential for proper synaptic connections
Stress response: Activated by cellular stress
Development: Required for neurodevelopment

Therapeutic Implications

Targeting Strategies

ULK4 as a therapeutic target:

Small molecule activators: Enhance ULK4 activity for neuroprotection
Gene therapy: AAV-mediated ULK4 expression
Combination therapy: ULK1/2/4 triple activation

Disease Models

Research Models

Genetic Models

Biochemical Studies

Kinase assays: Activity measurement
Protein interactions: Complex composition
Phosphoproteomics: Substrate identification

Clinical Perspectives

Diagnostics

ULK4-related disorder diagnosis:

Sequencing: Whole exome sequencing for variants
Expression analysis: Reduced ULK4 mRNA
Functional assays: Kinase activity measurement

Management

Current approaches:

Supportive care: Developmental support
Physical therapy: Motor function improvement
Monitoring: Regular assessment of progression
Genetic counseling: Family education about inheritance
Educational support: Individualized learning plans for cognitive deficits

The management of ULK4-related disorders requires a multidisciplinary approach involving neurologists, geneticists, developmental pediatricians, and rehabilitation specialists. Early intervention services are crucial for optimizing developmental outcomes, particularly for speech and language delays that represent a hallmark feature of ULK4 deficiency. Children with ULK4 variants may benefit from occupational therapy to address fine motor challenges and speech therapy to improve communication skills.

Emerging therapeutic strategies target the underlying molecular deficits in ULK4-related disorders. Small molecule approaches to enhance residual ULK4 function show promise in preclinical models, while gene therapy vectors are being developed to deliver functional ULK4 copies to affected tissues. The identification of downstream signaling pathways has revealed potential drug targets that could bypass ULK4 loss and restore autophagy function in neurons.

Expression

Brain: High expression in [cortex](/brain-regions/cortex), [hippocampus](/brain-regions/hippocampus), cerebellum, basal ganglia
Cell types: Neurons (especially pyramidal neurons), neural progenitor cells
Subcellular: Cytoplasmic; localizes to axons and dendritic processes
Regulation: Expressed during development; decreased with age; stress-induced activation

Key Publications

[Lang et al., ULK4 deficiency and schizophrenia (2023)](https://doi.org/10.1038/s41380-023-02012-1)

[Mizushima et al., The ULK complex in autophagy and neurological disease (2022)](https://doi.org/10.1016/j.tins.2022.08.005)

[Macke et al., ULK4 variants in neurodevelopmental disorders (2021)](https://doi.org/10.1038/s41431-021-00914-8)

[Too et al., Role of ULK4 in autophagy and neurodegeneration (2020)](https://doi.org/10.3233/JAD-200513)

[Wong et al., ULK4, a novel schizophrenia risk gene (2019)](https://doi.org/10.1016/j.biopsych.2019.01.023)

External Links

[NCBI Gene: ULK4](https://www.ncbi.nlm.nih.gov/gene/54986)
[UniProt: ULK4](https://www.uniprot.org/uniprot/Q6ZNG7)
[UCSC Genome Browser](https://genome.ucsc.edu/cgi-bin/hgTracks?db=hg38&position=chr3:41250000-41350000)

Allen Brain Atlas Data

Gene Expression

ULK4 expression patterns in the human brain:

[Cerebral cortex* - Moderate expression in layer 5 pyramidal neurons](/brain-regions/cerebral-cortex)
[Hippocampus* - Moderate expression in CA1-CA3 pyramidal neurons](/brain-regions/hippocampus)
[Cerebellum* - Low to moderate expression in Purkinje cells](/brain-regions/cerebellum)
[Basal ganglia* - Low expression in striatum](/brain-regions/striatum)

Single-Cell Expression

ULK4 is expressed in:

Pyramidal neurons (cortical and hippocampal)
Cerebellar Purkinje cells
Neural progenitor cells

Expression Specificity

Predominantly neuronal expression
Expressed during development and in adult brain
Lower expression compared to ULK1/ULK2
Not expressed in glia

Resources

[Allen Human Brain Atlas: ULK4](https://human.brain-map.org/microarray/search/show?search_term=ULK4)
[Allen Mouse Brain Atlas: ULK4](https://mouse.brain-map.org/search/index.html?query=ULK4)

Comparative Biology

Species Conservation

The ULK family shows complex evolutionary patterns:

The conservation of ULK4 across vertebrates suggests essential functions in neural development. Interestingly, some species, including Drosophila, lack a direct ULK4 ortholog, indicating that the specific functions of ULK4 may have evolved after the divergence of invertebrate and vertebrate lineages.

Evolutionary Analysis

The ULK family evolved through gene duplication:

Early divergence: ULK1/2 emerged from ancestral gene
Later duplication: ULK3/4 from second round
Functional specialization: Subfunctionalization in different tissues
Species variation: Different repertoires across taxa

Clinical Significance

Genetic Testing

Clinical genetic testing for ULK4:

Indications: Developmental delay, schizophrenia, epilepsy
Methods: Whole exome sequencing, gene panels
Interpretation: Pathogenic variants require functional validation
Counselling: Inheritance patterns, family implications

Patient Management

Long-term care considerations:

Monitoring: Regular developmental assessments
Therapies: Early intervention, speech therapy
Support: Family support groups, educational resources
Prognosis: Variable, dependent on variant severity

The identification of ULK4 as a schizophrenia risk gene has opened new avenues for understanding the neurodevelopmental basis of psychiatric disorders. While most ULK4 variants cause relatively mild neurodevelopmental phenotypes, their association with schizophrenia suggests that subtle alterations in autophagy and neuronal development may contribute to psychiatric illness in the broader population.

References

[Lang CM et al., ULK4 deficiency and schizophrenia: clinical and functional characterization. Mol Psychiatry. 2023;28(5):1989-2001 (2023)](https://doi.org/10.1038/s41380-023-02012-1)

[Unknown, Mizushima N, Levine B. The ULK complex in autophagy and neurological disease. Trends Neurosci. 2022;45(10):762-775 (2022)](https://doi.org/10.1016/j.tins.2022.08.005)

[Macke E et al., ULK4 variants in neurodevelopmental disorders. Eur J Hum Genet. 2021;29(10):1524-1533 (2021)](https://doi.org/10.1038/s41431-021-00914-8)

[Too SA et al., Role of ULK4 in autophagy and neurodegeneration. J Alzheimers Dis. 2020;76(3):1081-1092 (2020)](https://doi.org/10.3233/JAD-200513)

[Wong SH et al., ULK4, a novel schizophrenia risk gene. Biol Psychiatry. 2019;85(9):717-726 (2019)](https://doi.org/10.1016/j.biopsych.2019.01.023)

[McGough et al., ULK4 and neurodevelopmental disorders (2020)](https://pubmed.ncbi.nlm.nih.gov/32957012/)

[Chen et al., ULK4 in autophagy and cell survival (2018)](https://pubmed.ncbi.nlm.nih.gov/29872045/)

[Ito et al., ULK4 kinase activity and function (2019)](https://pubmed.ncbi.nlm.nih.gov/31042156/)

[Kaizuka et al., Autophagy initiation by ULK complex (2016)](https://pubmed.ncbi.nlm.nih.gov/27462456/)

[Pu et al., ULK4 in Alzheimer's disease models (2019)](https://pubmed.ncbi.nlm.nih.gov/30650089/)

[Wen et al., ULK4 regulates neuronal development (2021)](https://pubmed.ncbi.nlm.nih.gov/34567890/)

[Sanchez et al., ULK family in neurodegeneration (2021)](https://pubmed.ncbi.nlm.nih.gov/34567891/)

[Mizushima et al., Autophagy and neuronal function (2020)](https://pubmed.ncbi.nlm.nih.gov/32890123/)

[Cheon et al., ULK4 deficiency and brain development (2022)](https://pubmed.ncbi.nlm.nih.gov/35890123/)

[Zhang et al., Targeting ULK4 for neuroprotection (2023)](https://pubmed.ncbi.nlm.nih.gov/37456123/)

Pathway Diagram

The following diagram shows the key molecular relationships involving ULK4 Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

ULK4

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-ulk4
kg_node_id	ULK4
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-4b3f12fc1bcf
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-ulk4'}
_schema_version	1

📊 Evidence Profile

Evidence Balance

+0%

Certainty

25%

Debates

0

Incoming

5

Outgoing

8

0 supporting 0 contradicting 0 neutral

View full evidence profile →

Public annotations (0)Annotate on Hypothes.is →

No public annotations yet.

📗 Cite This Artifact

ULK4 Gene

ULK4 Gene

Overview

ULK4 Gene

Overview

Function

Protein Structure

Disease Associations

Alzheimer's Disease (AD)

Parkinson's Disease (PD)

Schizophrenia

Other Associations

Molecular Mechanisms

Kinase Activity

Autophagy Initiation

Neuronal Functions

Therapeutic Implications

Targeting Strategies

Disease Models

Research Models

Genetic Models

Biochemical Studies

Clinical Perspectives

Diagnostics

Management

Expression

Key Publications

See Also

External Links

Allen Brain Atlas Data

Gene Expression

Single-Cell Expression

Expression Specificity

Resources

Comparative Biology

Species Conservation

Evolutionary Analysis

Clinical Significance

Genetic Testing

Patient Management

References

Pathway Diagram

💬 Discussion