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MAPK4 Gene
MAPK4 Gene
Gene Overview
<div class="infobox infobox-gene">
<div class="infobox-header">Gene Information</div>
| Gene Symbol | MAPK4 |
|---|---|
| Full Name | Mitogen-Activated Protein Kinase 4 |
| Protein Name | ERK4 (Extracellular Signal-Regulated Kinase 4) |
| Chromosomal Location | 18q12.2 |
| NCBI Gene ID | [5595](https://www.ncbi.nlm.nih.gov/gene/5595) |
| OMIM | [617957](https://www.omim.org/entry/617957) |
| Ensembl ID | [ENSG00000116539](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000116539) |
| UniProt | [P31196](https://www.uniprot.org/uniprotkb/P31196/) |
| Associated Diseases | [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Cancer, Neuroinflammation |
| Expression | Brain (neurons, astrocytes), various tissues |
</div>
Overview
MAPK4 encodes ERK4 (Extracellular Signal-Regulated Kinase 4), a member of the mitogen-activated protein kinase (MAPK) family. Unlike classical MAPKs such as ERK1/2 (MAPK3/MAPK1), ERK4 is classified as an "atypical" MAPK because it lacks canonical activation-loop phosphorylation sites and does not require dual phosphorylation for activity. This distinctive regulation, combined with its expression in [neurons](/cell-types/neurons) and [astrocytes](/cell-types/astrocytes), positions MAPK4 as an important regulator of brain function and a potential contributor to neurodegenerative disease pathogenesis[@kim2015].
The MAPK family includes several subfamilies:
MAPK4 Gene
Gene Overview
<div class="infobox infobox-gene">
<div class="infobox-header">Gene Information</div>
| Gene Symbol | MAPK4 |
|---|---|
| Full Name | Mitogen-Activated Protein Kinase 4 |
| Protein Name | ERK4 (Extracellular Signal-Regulated Kinase 4) |
| Chromosomal Location | 18q12.2 |
| NCBI Gene ID | [5595](https://www.ncbi.nlm.nih.gov/gene/5595) |
| OMIM | [617957](https://www.omim.org/entry/617957) |
| Ensembl ID | [ENSG00000116539](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000116539) |
| UniProt | [P31196](https://www.uniprot.org/uniprotkb/P31196/) |
| Associated Diseases | [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Cancer, Neuroinflammation |
| Expression | Brain (neurons, astrocytes), various tissues |
</div>
Overview
MAPK4 encodes ERK4 (Extracellular Signal-Regulated Kinase 4), a member of the mitogen-activated protein kinase (MAPK) family. Unlike classical MAPKs such as ERK1/2 (MAPK3/MAPK1), ERK4 is classified as an "atypical" MAPK because it lacks canonical activation-loop phosphorylation sites and does not require dual phosphorylation for activity. This distinctive regulation, combined with its expression in [neurons](/cell-types/neurons) and [astrocytes](/cell-types/astrocytes), positions MAPK4 as an important regulator of brain function and a potential contributor to neurodegenerative disease pathogenesis[@kim2015].
The MAPK family includes several subfamilies:
- Conventional MAPKs: ERK1/2, JNK1-3, p38α-δ — require dual phosphorylation
- Atypical MAPKs: ERK3/4, ERK5, ERK7/8 — diverse activation mechanisms
ERK4 is expressed throughout the brain with particularly high levels in the [cortex](/brain-regions/cerebral-cortex), [hippocampus](/brain-regions/hippocampus), and [basal ganglia](/brain-regions/basal-ganglia). It participates in diverse signaling pathways controlling neuronal survival, synaptic function, stress responses, and inflammatory processes[@huang2020].
Gene Structure and Organization
The human MAPK4 gene has a complex genomic organization that reflects its multiple transcript variants and regulatory mechanisms.
Genomic Organization
| Feature | Details |
|---------|---------|
| Chromosome | 18q12.2 |
| Genomic Span | ~77 kb |
| Exons | 16 coding exons |
| Transcript Length | ~4.0 kb |
| Protein Length | 632 amino acids |
| Molecular Weight | ~65 kDa |
Comparison with Other MAPKs
| Kinase | Gene | Size (aa) | Phosphorylation Sites | Activation |
|--------|------|-----------|---------------------|------------|
| ERK1 | MAPK3 | 384 | T202/Y204 | Dual phosphorylation |
| ERK2 | MAPK1 | 360 | T185/Y187 | Dual phosphorylation |
| ERK3 | MAPK6 | 398 | S189 (unique) | Single site |
| ERK4 | MAPK4 | 632 | None canonical | Kinase-independent |
| ERK5 | MAPK7 | 816 | T218/Y220 | Dual phosphorylation |
| JNK1 | MAPK8 | 384 | T183/Y185 | Dual phosphorylation |
| p38α | MAPK14 | 360 | T180/Y182 | Dual phosphorylation |
Transcript Variants
Protein Structure and Biochemistry
ERK4 has a distinctive structure that reflects its atypical nature:
Structural Domains
Atypical Kinase Properties
| Property | Conventional MAPKs | ERK4 |
|----------|-------------------|------|
| Activation loop | Requires dual phosphorylation | No phosphorylation required |
| Catalytic activity | Low without activation | Constitutively active |
| Regulation | By upstream kinases | By protein interactions |
| Substrate specificity | Phosphorylation-dependent | Interaction-dependent |
ERK4 Kinase Activity
Despite being classified as an atypical MAPK, ERK4 has genuine kinase activity:
Normal Physiological Functions
Neuronal Signaling
ERK4 participates in multiple neuronal signaling pathways[@kim2020]:
Key Functions
Stress Responses
ERK4 responds to various cellular stresses:
| Stress Type | ERK4 Response | Outcome |
|-------------|---------------|---------|
| Oxidative Stress | Activation | Adaptive response |
| DNA Damage | Involvement | Cell cycle control |
| ER Stress | Modulation | Unfolded protein response |
| Osmotic Stress | Response | Volume regulation |
Neuroinflammation
ERK4 in glial cells regulates inflammatory responses[@caruso2022]:
- Astrocyte Activation: Controls inflammatory cytokine production
- Microglial Function: Modulates immune surveillance
- BBB Function: Affects endothelial cell signaling
- Neuron-Glia Communication: Bidirectional signaling
Brain Region Distribution
| Brain Region | ERK4 Expression | Cell Type |
|--------------|-----------------|-----------|
| Cerebral Cortex | High | Pyramidal neurons, interneurons |
| Hippocampus | High | CA1-CA3 pyramidal cells, dentate granule cells |
| Basal Ganglia | Moderate | Medium spiny neurons |
| Cerebellum | Moderate | Purkinje cells |
| Brainstem | Moderate | Various neuron types |
Disease Associations
Alzheimer's Disease
ERK4 is implicated in [Alzheimer's disease](/diseases/alzheimers-disease) pathogenesis through multiple mechanisms[@sun2021]:
Evidence
- Expression Changes: Altered ERK4 levels in AD brain
- Tau Pathology: ERK4 can phosphorylate tau (in vitro)
- Amyloid Effects: Aβ modulates ERK4 signaling
- Synaptic Dysfunction: ERK4 in synaptic decline
Mechanisms
Therapeutic Implications
- ERK4 Modulators: Could restore normal signaling
- Downstream Effectors: Target substrates for intervention
- Combination Therapies: With anti-amyloid approaches
Parkinson's Disease
ERK4 involvement in [Parkinson's disease](/diseases/parkinsons-disease):
- Dopaminergic Neurons: ERK4 regulates survival
- α-Synuclein: Interaction with synuclein pathology
- Mitochondrial Stress: ERK4 in stress response
- Neuroinflammation: Glial ERK4 in PD progression
Cancer
ERK4 has complex, often oncogenic roles in cancer[@zhou2017]:
| Cancer Type | ERK4 Role | Evidence |
|-------------|-----------|----------|
| Breast Cancer | Oncogenic | Overexpression, promotes proliferation |
| Lung Cancer | Context-dependent | Both pro- and anti-tumorigenic |
| Colorectal Cancer | Oncogenic | Amplification, high expression |
| Glioma | Oncogenic | Promotes growth and invasion |
Mechanisms in Cancer
Neuroinflammatory Disorders
ERK4 contributes to excessive inflammation in:
- Multiple Sclerosis: Demyelination and inflammation
- Traumatic Brain Injury: Post-injury inflammation
- Stroke: Ischemic injury responses
- ALS: Glial inflammation
Research on ERK4 Deficiency
A key study demonstrates the neuroprotective potential of ERK4 deficiency[@huang2020]:
Key Findings
Implications
- Therapeutic Targeting: ERK4 inhibition may be beneficial
- Selective Inhibition: Brain-specific targeting needed
- Kinase-independent Functions: May also be important
Therapeutic Targeting
Challenges in Targeting ERK4
Potential Strategies
| Approach | Status | Considerations |
|---------|--------|----------------|
| ATP-competitive inhibitors | Preclinical | May not inhibit all functions |
| Allosteric inhibitors | Preclinical | Better selectivity potential |
| Protein-protein interaction blockers | Discovery | Challenge of drugability |
| Gene therapy (knockdown) | Preclinical | Long-lasting effect |
Specific Considerations for Neurodegeneration
- Anti-inflammatory Effects: Primary benefit
- Neuroprotection: Direct neuronal effects
- Synaptic Function: May improve cognition
- Disease Modification: Potential for slowing progression
Research Directions and Knowledge Gaps
Outstanding Questions
Emerging Research Areas
- Structural Biology: Cryo-EM of ERK4 complexes
- Proteomics: Phosphoproteomics of ERK4 substrates
- Single-Cell Analysis: Cell-type specific functions
- Animal Models: Conditional knockouts for tissue-specific studies
Cross-References and Related Entities
Related Genes and Proteins
- [MAPK1](/genes/mapk1) - ERK2, classical MAPK
- [MAPK3](/genes/mapk3) - ERK1, classical MAPK
- [MAPK6](/genes/mapk6) - ERK3, atypical MAPK
- [MAPK7](/genes/mapk7) - ERK5, atypical MAPK
- [RSK1](/genes/rsk1) - ERK4 substrate
Pathways
- [MAPK Signaling](/mechanisms/mapk-signaling)
- [Stress-Activated Kinases](/mechanisms/stress-kinases)
- [Cell Survival Pathways](/mechanisms/cell-survival)
- [Neuroinflammation](/mechanisms/neuroinflammation)
Diseases
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Multiple Sclerosis](/diseases/multiple-sclerosis)
- [Stroke](/diseases/stroke)
Related Proteins
- [Tau](/proteins/tau) - Phosphorylation target
- [Amyloid Beta](/proteins/amyloid-beta) - Pathological trigger
Key Publications
External Resources
- [NCBI Gene: MAPK4](https://www.ncbi.nlm.nih.gov/gene/5595)
- [UniProt: ERK4 (P31196)](https://www.uniprot.org/uniprotkb/P31196/)
- [GeneCards: MAPK4](https://www.genecards.org/cgi-bin/carddisp.pl?gene=MAPK4)
- [OMIM: 617957](https://www.omim.org/entry/617957)
- [Human Protein Atlas: MAPK4](https://www.proteinatlas.org/ENSG00000116539-MAPK4)
- [KEGG: MAPK Signaling Pathway](https://www.genome.jp/pathway/map04010)
References
▸Metadataorigin_type: v1_polymorphic_backfill
| slug | genes-mapk4 |
| kg_node_id | MAPK4 |
| entity_type | gene |
| origin_type | v1_polymorphic_backfill |
| source_table | wiki_pages |
| wiki_page_id | wp-4cc80737e4ef |
| __merged_from | {'merged_at': '2026-05-13', 'unprefixed_id': 'genes-mapk4'} |
| _schema_version | 1 |
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