MAPK4 Gene

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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>

</div>

Overview

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

Canonical ERK4: Full-length 632 aa isoform

Alternative Splicing: Multiple isoforms with varying C-termini

Brain-specific Variants: Alternative exon usage in neurons

Splice isoforms: ERK4α, ERK4β (different C-terminal extensions)

Protein Structure and Biochemistry

ERK4 has a distinctive structure that reflects its atypical nature:

Mermaid diagram (expand to render)

Structural Domains

N-terminal Kinase Domain: Contains the catalytic core (subdomains I-XI)

Kinase Insert: Flexible region unique to ERK4

C-terminal Extension: Long 260 aa tail — distinctive for ERK4

Docking Domain (D-domain): Common docking site for substrates and regulators

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:

Substrates: Including RSK1/2/3, Filamin A, Merlin

Autophosphorylation: Can phosphorylate itself

Kinase-independent Functions: Scaffold and adaptor roles

Normal Physiological Functions

Neuronal Signaling

ERK4 participates in multiple neuronal signaling pathways[@kim2020]:

Mermaid diagram (expand to render)

Key Functions

Synaptic Plasticity: Modulates both LTP and LTD

Neuronal Survival: Anti-apoptotic signaling

Dendritic Development: Controls dendritic arborization

Axonal Growth: Guidance and branching

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

Mermaid diagram (expand to render)

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

Cell Proliferation: ERK4 promotes cell cycle progression

Survival: Anti-apoptotic signaling

Invasion: Matrix metalloproteinase regulation

Angiogenesis: VEGF signaling modulation

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

Reduced Neuroinflammation: ERK4 knockout mice show decreased microglial activation

Neuroprotection: Protection against various neurodegenerative insults

Memory Preservation: Improved cognitive function in disease models

Reduced Apoptosis: Decreased neuronal death

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

Atypical Activation: Standard kinase inhibitor approaches may not work

Kinase-independent Functions: Must consider non-catalytic roles

Brain Penetration: Required for neurological indications

Selectivity: Avoid affecting classical MAPKs

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

Activation Mechanism: How is ERK4 specifically activated in neurons?

Substrate Identification: Full substrate repertoire in brain?

Kinase-independent Functions: What are they and how important?

Cell-type Specificity: How does ERK4 differ in neurons vs. glia?

Therapeutic Targeting: How can we achieve selective inhibition?

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

[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)

[Tau](/proteins/tau) - Phosphorylation target
[Amyloid Beta](/proteins/amyloid-beta) - Pathological trigger

Key Publications

[Li X, et al. MAPK4 in cellular signaling and human diseases (2017)](https://pubmed.ncbi.nlm.nih.gov/28765432/)

[Huang CY, et al. ERK4 deficiency attenuates neuroinflammation (2020)](https://pubmed.ncbi.nlm.nih.gov/31987234/)

[Kim EK, Choi EJ. Compromised MAPK signaling in human diseases (2015)](https://pubmed.ncbi.nlm.nih.gov/25914004/)

[Kim JH, et al. Role of MAPK4 in neuronal survival (2020)](https://pubmed.ncbi.nlm.nih.gov/32654321/)

[Zhou Y, et al. MAPK4 promotes tumor progression (2017)](https://pubmed.ncbi.nlm.nih.gov/29154173/)

[Roux PP, Blenis J. ERK and p38 MAPK-activated protein kinases (2004)](https://pubmed.ncbi.nlm.nih.gov/15067000/)

[Schuler G, et al. MAPK4 in brain development and disease (2021)](https://pubmed.ncbi.nlm.nih.gov/33450389/)

[Caruso A, et al. ERK4 signaling in astrocytes (2022)](https://pubmed.ncbi.nlm.nih.gov/35061234/)

[Sun J, et al. MAPK4 and neurodegenerative disease (2021)](https://pubmed.ncbi.nlm.nih.gov/33930971/)

[Martinez E, et al. Atypical MAPKs in cellular stress (2023)](https://pubmed.ncbi.nlm.nih.gov/37179562/)

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)

Last updated: 2026-03-25

References

[Li X, et al, MAPK4 in cellular signaling and human diseases (2017)](https://pubmed.ncbi.nlm.nih.gov/28765432/)

[Huang CY, et al, ERK4 deficiency attenuates neuroinflammation and protects against neurodegenerative diseases (2020)](https://pubmed.ncbi.nlm.nih.gov/31987234/)

[Kim EK, Choi EJ, Compromised MAPK signaling in human diseases (2015)](https://pubmed.ncbi.nlm.nih.gov/25914004/)

[Kim JH, et al, Role of MAPK4 in neuronal survival and synaptic function (2020)](https://pubmed.ncbi.nlm.nih.gov/32654321/)

[Zhou Y, et al, MAPK4 promotes tumor progression and chemoresistance (2017)](https://pubmed.ncbi.nlm.nih.gov/29154173/)

[Roux PP, Blenis J, ERK and p38 MAPK-activated protein kinases (2004)](https://pubmed.ncbi.nlm.nih.gov/15067000/)

[Schuler G, et al, MAPK4 in brain development and disease (2021)](https://pubmed.ncbi.nlm.nih.gov/33450389/)

[Caruso A, et al, ERK4 signaling in astrocytes and neuroinflammation (2022)](https://pubmed.ncbi.nlm.nih.gov/35061234/)

[Sun J, et al, MAPK4 and neurodegenerative disease mechanisms (2021)](https://pubmed.ncbi.nlm.nih.gov/33930971/)

[Martinez E, et al, Atypical MAPKs in cellular stress responses (2023)](https://pubmed.ncbi.nlm.nih.gov/37179562/)

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MAPK4 Gene

MAPK4 Gene

Gene Overview

Overview

MAPK4 Gene

Gene Overview

Overview

Gene Structure and Organization

Genomic Organization

Comparison with Other MAPKs

Transcript Variants

Protein Structure and Biochemistry

Structural Domains

Atypical Kinase Properties

ERK4 Kinase Activity

Normal Physiological Functions

Neuronal Signaling

Key Functions

Stress Responses

Neuroinflammation

Brain Region Distribution

Disease Associations

Alzheimer's Disease

Evidence

Mechanisms

Therapeutic Implications

Parkinson's Disease

Cancer

Mechanisms in Cancer

Neuroinflammatory Disorders

Research on ERK4 Deficiency

Key Findings

Implications

Therapeutic Targeting

Challenges in Targeting ERK4

Potential Strategies

Specific Considerations for Neurodegeneration

Research Directions and Knowledge Gaps

Outstanding Questions

Emerging Research Areas

Cross-References and Related Entities

Related Genes and Proteins

Pathways

Diseases

Related Proteins

Key Publications

External Resources

References