p38 MAPK Protein

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p38 MAPK Protein

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p38 MAPK Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">p38 MAPK Protein</th>
</tr>
<tr>
<td class="label">Gene Symbols</td>
<td>MAPK14 (p38α), MAPK11 (p38β), MAPK12 (p38γ), MAPK13 (p38δ)</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>MAPK14: 6p21.31, MAPK11: 22q13.13, MAPK12: 15q21.2, MAPK13: 6p21.31</td>
</tr>
<tr>
<td class="label">UniProt IDs</td>
<td>Q16539 (p38α), P53778 (p38β), P53779 (p38γ), O15264 (p38δ)</td>
</tr>
<tr>
<td class="label">Molecular Weight</td>
<td>~38-40 kDa per isoform</td>
</tr>
<tr>
<td class="label">Brain Expression</td>
<td>p38α: ubiquitous in neurons, microglia, astrocytes; p38β: lower expression; p38γ/p38δ: restricted</td>
</tr>
<tr>
<td class="label">Substrate</td>
<td>Function</td>
</tr>
<tr>
<td class="label">ATF2</td>
<td>Transcription factor</td>
</tr>
<tr>
<td class="label">CHOP (DDIT3)</td>
<td>Transcription factor</td>
</tr>
<tr>
<td class="label">MAPKAPK2/3</td>
<td>Kinase</td>
</tr>
<tr>
<td class="label">Tau (MAPT)</td>
<td>Cytoskeletal protein</td>
</tr>
<tr>
<td class="label">MSK1/2</td>
<td>Kinase</td>
</tr>
<tr>
<td class="label">Hsp27</td>
<td>Chaperone</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Selectivity</td>
</tr>
<tr>
<td class="label">SB203580</td>
<td>Broad p38 inhibitor</td>
</tr>
<tr>
<td class="label">PH-797804</td>
<td>Selective p38 inhibitor</td>
</tr>
<tr>
<td class="label">Losmapimod</td>
<td>p38α/β inhibitor</td>
</tr>
<tr>
<td class="label">Neflamapimod (VX-745)</td>
<td>Selective p38α</td>
</tr>
<tr>
<td class="label">Pamapimod</td>
<td>p38 inhibitor</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">MKK3</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">MKK6</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">ATF2</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">CHOP (DDIT3)</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">MAPKAPK2</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">Tau (MAPT)</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">Hsp27</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">MSK1/2</td>
<td>Phosphorylation</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/alzheimer's-disease" style="color:#ef9a9a">ALZHEIMER'S DISEASE</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1316 edges</a></td>
</tr>
</table>

Pathway Diagram

Mermaid diagram (expand to render)

p38 MAPK (mitogen-activated protein kinase 14) is a family of serine/threonine protein kinases activated by cellular stress, inflammatory cytokines, and environmental insults. The p38 family comprises four isoforms: p38alpha (MAPK14), p38beta (MAPK11), p38gamma (MAPK12), and p38delta (MAPK13). In the brain, p38alpha is the predominant isoform expressed in [neurons](/entities/neurons), [microglia](/cell-types/microglia-neuroinflammation), and [astrocytes](/entities/astrocytes). p38 is centrally implicated in [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and other neurodegenerative disorders through its regulation of neuroinflammation, [tau](/proteins/tau) phosphorylation, and neuronal apoptosis. [@corr2021]

Gene and Isoforms

Structure

p38 MAPK adopts a typical bilobal kinase structure with an N-terminal activation segment containing the Thr-Gly-Tyr (TGY) dual phosphorylation motif. Activation requires phosphorylation of both Thr180 and Tyr182 by upstream MAPKKs (MKK3 and MKK6). The kinase contains a docking domain for interaction with substrates and regulators. p38α, the primary brain isoform, is a 360-amino acid protein that forms dimers upon activation, which is required for full kinase activity. [@falgicchia2020]

Normal Function

Activation Mechanisms

p38 is activated through a canonical kinase cascade:

Upstream stress signals: Pro-inflammatory cytokines (IL-1β, TNF-α), oxidative stress, UV radiation, heat shock, and ischemia trigger activation

MAPKKK layer: TAK1, MEKK4, and MLK3 activate MKK3/6

MKK3/MKK6 phosphorylation: These specific MAPKKs dual-phosphorylate p38 at Thr180/Tyr182

Substrate phosphorylation: Activated p38 translocates to various cellular compartments to phosphorylate targets

Key Substrates

Physiological Roles

In the healthy brain, p38 regulates:

Inflammatory response to injury and infection
Cell cycle progression and survival decisions
Synaptic plasticity and memory formation (p38 in LTP)
Cytokine production in glial cells
Stress-responsive gene expression

Role in Alzheimer's Disease

p38 is strongly activated in [Alzheimer's disease](/diseases/alzheimers-disease) brain tissue, particularly in microglia surrounding amyloid plaques and in vulnerable neurons. [@gee2020]

Neuroinflammation

p38 is the master regulator of pro-inflammatory cytokine production in microglia:

IL-1β and TNF-α: p38 MAPK drives transcription and release of these key inflammatory cytokines
Microglial activation: Aβ oligomers activate p38 in microglia, creating a vicious cycle of inflammation and plaque accumulation
NLRP3 inflammasome: p38 contributes to NLRP3 activation and IL-1β maturation
Synaptic pruning: p38-mediated inflammation may accelerate pathological synaptic pruning in AD

Selective p38α/β inhibition with compounds like neflamapimod (PH-797804 derivative) reduces microglial activation and improves cognitive function in 5XFAD mouse models. [@gee2020]

Tau Pathology

p38 directly phosphorylates [tau](/proteins/tau) at multiple disease-relevant sites:

Ser202/Thr205: Sites targeted by p38, coinciding with AT8 epitope
Thr231: p38 phosphorylates this site, which is associated with microtubule instability
Colocalization: p-p38 immunoreactivity is found in neurons bearing neurofibrillary tangles
Correlation with Braak staging: p38 activation increases with disease severity

Aβ and Synaptic Dysfunction

[Aβ](/proteins/amyloid-beta) oligomers activate p38 through multiple mechanisms:

RAGE-mediated signaling
Direct activation by oxidative stress
NMDA receptor-dependent pathways

p38 activation in synapses contributes to:

NMDA receptor dysfunction
Spine loss and synaptic depression
Impaired LTP (long-term potentiation)
Memory consolidation deficits

p38 inhibition reverses Aβ-induced synaptic dysfunction and improves spatial memory in animal models. [@falgicchia2020]

Therapeutic Targeting

Neflamapimod (a p38α-selective inhibitor) has been tested in clinical trials for AD:

Phase 2 trials showed improvement in episodic memory in early AD patients (NCT03422682)
Targets synaptic dysfunction rather than amyloid or tau pathology
Generally well-tolerated with good CNS penetration

Losmapimod has also been investigated for its effects on neuroinflammation and cognitive function in AD. [@munoz2022]

Role in Parkinson's Disease

In [Parkinson's disease](/diseases/parkinsons-disease), p38 drives neuroinflammation and dopaminergic neuron death:

Microglial Activation

p38 is activated in microglia in the substantia nigra of PD patients and animal models
MPTP and 6-OHDA models show p38-dependent production of NO, IL-1β, and TNF-α
p38 in microglia promotes a pro-inflammatory (M1-like) phenotype
Inhibition of microglial p38 reduces dopaminergic neuron loss

Dopaminergic Neuron Vulnerability

p38 is activated in dopaminergic neurons in PD
Mitochondrial toxins (MPP+, 6-OHDA) activate p38 through oxidative stress
p38 contributes to apoptosis of dopaminergic neurons through:
Direct activation of apoptotic pathways (caspase-3)
Upregulation of pro-apoptotic genes (Bim, Bax)
ER stress response (CHOP activation)
p38 inhibitors are protective in MPTP and 6-OHDA animal models

α-Synuclein and Neuroinflammation

[α-Synuclein](/proteins/alpha-synuclein) aggregates activate p38:

Extracellular α-synuclein is taken up by microglia via endocytosis
This activates p38 and triggers inflammatory cytokine release
p38-mediated inflammation may drive further α-synuclein aggregation and spread

Role in Other Neurodegenerative Disorders

Multiple Sclerosis

p38 drives demyelination and oligodendrocyte death in MS models
p38 in T cells promotes their migration across the blood-brain barrier
p38 inhibitors reduce disease severity in EAE (experimental autoimmune encephalomyelitis)

Stroke and Ischemic Brain Injury

p38 is rapidly activated in response to cerebral ischemia
Contributes to excitotoxicity, inflammation, and blood-brain barrier disruption
p38 inhibitors reduce infarct volume when given within therapeutic windows

Amyotrophic Lateral Sclerosis (ALS)

p38 is activated in motor neurons and glia in ALS
Contributes to inflammatory activation and motor neuron death
SOD1 and TDP-43 models show p38-dependent toxicity

Therapeutic Targeting

Small Molecule Inhibitors

Clinical Status

p38 inhibitors have been extensively tested in inflammatory diseases (rheumatoid arthritis, COPD, psoriasis) with mixed results
CNS penetration has been a challenge for many first-generation p38 inhibitors
Neflamapimod has shown signals of cognitive benefit in early AD (Phase 2b, NCT03422682)
Current focus is on selective p38α inhibitors with improved brain penetration and minimal peripheral toxicity

Challenges

Peripheral inflammation: Systemic p38 inhibition can cause liver toxicity and suppress beneficial inflammation
CNS penetration: Early compounds did not adequately cross the blood-brain barrier
Biomarkers: Need for patient selection biomarkers based on p38 activation status
Timing: Optimal therapeutic window may be early in disease course

Protein Interactions

References

[Falcicchia C, et al., Involvement of p38 MAPK in Synaptic Function and Dysfunction. International Journal of Molecular Sciences (2020)](https://pubmed.ncbi.nlm.nih.gov/32781522/)

[Gee MS, et al., A selective p38alpha/beta MAPK inhibitor alleviates neuropathology and cognitive impairment, and modulates microglia function in 5XFAD mouse. Acta Neuropathologica Communications (2020)](https://pubmed.ncbi.nlm.nih.gov/32317025/)

[Germann UA, Alam JJ, p38alpha MAPK Signaling-A Robust Therapeutic Target for Rab5-Mediated Neurodegenerative Disease. International Journal of Molecular Sciences (2020)](https://pubmed.ncbi.nlm.nih.gov/32751991/)

[Munoz L, Ammit AJ, Targeting p38 MAPK pathway for the treatment of Alzheimer's disease. Neuropharmacology (2022)](https://pubmed.ncbi.nlm.nih.gov/34808159/)

[Corr理解和描述., et al., p38 MAPK in neuroinflammation and neurodegeneration. Cellular and Molecular Life Sciences (2021)](https://pubmed.ncbi.nlm.nih.gov/34536112/)

Pathway Diagram

The following diagram shows the key molecular relationships involving p38 MAPK Protein discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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p38 MAPK Protein

p38 MAPK Protein

p38 MAPK Protein

Pathway Diagram

Gene and Isoforms

Structure

Normal Function

Activation Mechanisms

Key Substrates

Physiological Roles

Role in Alzheimer's Disease

Neuroinflammation

Tau Pathology

Aβ and Synaptic Dysfunction

Therapeutic Targeting

Role in Parkinson's Disease

Microglial Activation

Dopaminergic Neuron Vulnerability

α-Synuclein and Neuroinflammation

Role in Other Neurodegenerative Disorders

Multiple Sclerosis

Stroke and Ischemic Brain Injury

Amyotrophic Lateral Sclerosis (ALS)

Therapeutic Targeting

Small Molecule Inhibitors

Clinical Status

Challenges

Protein Interactions

See Also

References

Pathway Diagram