PERK Protein

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PERK Protein

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PERK Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">PERK Protein</th>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Relationship</td>
</tr>
<tr>
<td class="label">BiP/GRP78</td>
<td>Inhibitory binding partner</td>
</tr>
<tr>
<td class="label">[eIF2α](/proteins/eif2a)</td>
<td>Phosphorylation substrate</td>
</tr>
<tr>
<td class="label">ATF4</td>
<td>Downstream transcription factor</td>
</tr>
<tr>
<td class="label">CHOP</td>
<td>ATF4 target</td>
</tr>
<tr>
<td class="label">GADD34</td>
<td>Phosphatase regulator</td>
</tr>
<tr>
<td class="label">Nrf2</td>
<td>PERK phosphorylates</td>
</tr>
<tr>
<td class="label">FoxO1</td>
<td>PERK phosphorylates</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/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">390 edges</a></td>
</tr>
</table>

...

PERK Protein

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">PERK Protein</th>
</tr>
<tr>
<td class="label">Interactor</td>
<td>Relationship</td>
</tr>
<tr>
<td class="label">BiP/GRP78</td>
<td>Inhibitory binding partner</td>
</tr>
<tr>
<td class="label">[eIF2α](/proteins/eif2a)</td>
<td>Phosphorylation substrate</td>
</tr>
<tr>
<td class="label">ATF4</td>
<td>Downstream transcription factor</td>
</tr>
<tr>
<td class="label">CHOP</td>
<td>ATF4 target</td>
</tr>
<tr>
<td class="label">GADD34</td>
<td>Phosphatase regulator</td>
</tr>
<tr>
<td class="label">Nrf2</td>
<td>PERK phosphorylates</td>
</tr>
<tr>
<td class="label">FoxO1</td>
<td>PERK phosphorylates</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/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">390 edges</a></td>
</tr>
</table>

<div style="float: right; margin: 0 0 1em 1em; padding: 1em; background: #f8f9fa; border: 1px solid #a2a9b1; border-radius: 5px; font-size: 0.9em; width: 280px;">
<strong>PERK</strong><br>
<i>Protein Kinase R-like ER Kinase</i>
<hr>
<strong>Symbol:</strong> EIF2AK3 / PEK<br>
<strong>UniProt:</strong> [Q9NZJ5](https://www.uniprot.org/uniprot/Q9NZJ5)<br>
<strong>Gene:</strong> [EIF2AK3](/entities/eif2ak3)<br>
<strong>Molecular Weight:</strong> 125 kDa<br>
<strong>Location:</strong> ER membrane (Type I transmembrane)<br>
<strong>PDB:</strong> [3QD2](https://www.rcsb.org/structure/3QD2), [5YVA](https://www.rcsb.org/structure/5YVA)
</div>

Overview

Protein kinase R-like endoplasmic reticulum kinase (PERK, also known as EIF2AK3 or PEK) is a type I transmembrane protein kinase localized to the ER membrane. As one of the three major sensors of the [unfolded protein response (UPR)](/mechanisms/er-stress-upr), PERK couples ER stress to translational attenuation through phosphorylation of [eIF2α](/proteins/eif2a) at Ser51[@harding2000].

PERK activation represents a critical adaptive mechanism during protein misfolding stress, but chronic PERK signaling contributes to neurodegeneration in Alzheimer's disease, Parkinson's disease, ALS, Huntington's disease, and prion disorders[@mercado2020].

Structure and Domains

PERK contains:

N-terminal luminal domain (1-576): Senses misfolded proteins in the ER lumen; interacts with BiP/GRP78
Transmembrane domain (577-597): Anchors PERK to ER membrane
Cytosolic kinase domain (666-1114): Serine/threonine kinase activity; phosphorylates eIF2α

Activation mechanism: Under normal conditions, BiP binds the luminal domain, maintaining PERK monomeric and inactive. ER stress causes BiP release, allowing PERK dimerization, trans-autophosphorylation, and activation[@carrara2015].

Normal Function

Unfolded Protein Response

PERK is one of three ER stress sensors (along with [IRE1](/proteins/ire1) and ATF6):

Stress sensing: Accumulation of unfolded proteins in the ER lumen

BiP release: Competition between misfolded proteins and PERK for BiP binding

Dimerization: Luminal domains interact, bringing kinase domains together

Autophosphorylation: Trans-phosphorylation at activation loop residues

eIF2α phosphorylation: Converts eIF2α to a potent inhibitor of eIF2B

Integrated Stress Response

PERK is one of four eIF2α kinases (with GCN2, PKR, HRI), integrating diverse stress signals into a common translational response[@wek2006]:

Global translation inhibition: Reduces protein load on stressed ER
Selective ATF4 translation: Activates stress-adaptive gene expression
Redox homeostasis: ATF4 induces antioxidant genes
Amino acid metabolism: Upregulates amino acid transporters and biosynthesis

Physiological Roles

Pancreatic β-cells: Essential for high secretory demand
Plasma cells: Supports antibody production
Osteoblasts: Bone matrix secretion
Development: PERK mutations cause Wolcott-Rallison syndrome

Role in Neurodegeneration

Alzheimer's Disease

In AD, PERK activation occurs early and intensifies with disease progression[@hoozemans2005]:

[Aβ](/proteins/amyloid-beta) oligomers: Activate PERK in cultured [neurons](/entities/neurons)
[Tau](/proteins/tau) aggregates: Trigger ER stress and PERK activation
Hippocampal neurons: Elevated p-PERK and p-eIF2α in AD brains
[BACE1](/entities/bace1) paradox: PERK signaling increases BACE1 translation via uORF bypass, accelerating Aβ production
Synaptic dysfunction: Impaired [LTP](/mechanisms/long-term-potentiation) and memory consolidation

Evidence: Post-mortem AD brains show p-PERK immunoreactivity in neurons with neurofibrillary tangles[@hoozemans2007].

Parkinson's Disease

[α-synuclein](/proteins/alpha-synuclein): Overexpression or aggregation activates PERK
Dopaminergic vulnerability: Substantia nigra neurons show elevated p-PERK
MPTP models: PERK activation in nigrostriatal pathway
LRRK2: Pathogenic variants may enhance ER stress susceptibility

Clinical correlation: p-PERK levels correlate with Lewy body density in PD patients[@baek2022].

Huntington's Disease

PolyQ-expanded [huntingtin](/proteins/huntingtin): Disrupts ER calcium homeostasis
[UPR](/entities/unfolded-protein-response) activation: Chronic PERK signaling in striatal neurons
R6/2 and HD-N171-82Q models: Elevated p-PERK and p-eIF2α
Synaptic defects: Impaired dendritic protein synthesis

ALS and FTD

SOD1 mutations: Mutant SOD1 activates PERK in motor neurons
[TDP-43](/mechanisms/tdp-43-proteinopathy): Cytoplasmic aggregates trigger ER stress
[C9orf72](/entities/c9orf72): Dipeptide repeat proteins activate PERK
FUS: Mutant FUS induces UPR activation

Prion Diseases

PrP^Sc accumulation: Activates all three UPR branches
PERK dependency: Genetic PERK reduction delays prion disease
Therapeutic window: PERK inhibition after symptom onset still effective in mice

Therapeutic Targeting

PERK Inhibitors

GSK2606414:

Potent and selective PERK inhibitor (IC50 = 0.4 nM)
Neuroprotective in prion disease models
Extended survival in tauopathy mice
Limitation: Pancreatic toxicity from β-cell dysfunction

GSK2656157:

Improved brain penetration
Reduced pancreatic toxicity at neuroprotective doses
Protective in 5xFAD Alzheimer's model[@gsk2021]

AMG44:

Next-generation PERK inhibitor
Improved therapeutic window

ISRIB

Rather than inhibiting PERK directly, ISRIB stabilizes eIF2B to counteract p-eIF2α-mediated translational inhibition[@sidrauski2015]:

Downstream of PERK
Restores translation without affecting PERK signaling
Neuroprotective in multiple neurodegeneration models
Cognitive enhancement in healthy animals

Gene Therapy Approaches

PERK heterozygosity: Reduces neurodegeneration in mouse models
Conditional knockout: Temporal control to avoid developmental effects
RNA interference: Reduce PERK expression in vulnerable neurons

Key Interactions

External Links

[UniProt: Q9NZJ5](https://www.uniprot.org/uniprot/Q9NZJ5)
[PDB structures](https://www.rcsb.org/search?q=uniprot:Q9NZJ5)

References

[Harding HP et al. Regulated translation initiation controls stress-induced gene expression in mammalian cells. Mol Cell. 2000;6(5):1099-1108, https://doi.org/10.1016/S1097-2765(00)00108-8 (2000)](https://doi.org/10.1016/S1097-2765(00)

[Mercado G et al. ER stress and neurodegeneration: Pathogenic mechanisms and therapeutic opportunities. Curr Top Med Chem. 2020;20(18):1621-1652, https://doi.org/10.2174/1568026620666200416092946 (2020)](https://doi.org/10.2174/1568026620666200416092946](https://doi.org/10.2174/1568026620666200416092946](https://doi.org/10.2174/1568026620666200416092946)

[Carrara G et al. Characterization of the unfolded protein response in mammalian cells. Methods Mol Biol. 2015;1292:37-49, https://doi.org/10.1007/978-1-4939-2522-3_4 (2015)](https://doi.org/10.1007/978-1-4939-2522-3_4](https://doi.org/10.1007/978-1-4939-2522-3_4](https://doi.org/10.1007/978-1-4939-2522-3_4)

[Wek RC et al. Coping with stress: eIF2 kinases and translational control. Biochem Soc Trans. 2006;34(Pt 1):7-11, https://doi.org/10.1042/BST20060007 (2006)](https://doi.org/10.1042/BST20060007](https://doi.org/10.1042/BST20060007](https://doi.org/10.1042/BST20060007)

[Hoozemans JJM et al. The unfolded protein response is activated in Alzheimer's disease. Acta Neuropathol. 2005;110(2):165-172, https://doi.org/10.1007/s00401-005-1038-0 (2005)](https://doi.org/10.1007/s00401-005-1038-0](https://doi.org/10.1007/s00401-005-1038-0](https://doi.org/10.1007/s00401-005-1038-0)

[Hoozemans JJM et al. Activation of the unfolded protein response in Parkinson's disease. Biochem Biophys Res Commun. 2007;354(3):707-711, https://doi.org/10.1016/j.bbrc.2006.12.169 (2007)](https://doi.org/10.1016/j.bbrc.2006.12.169](https://doi.org/10.1016/j.bbrc.2006.12.169](https://doi.org/10.1016/j.bbrc.2006.12.169)

[Baek JH et al. The PERK signaling pathway in Alzheimer's and Parkinson's disease. Front Neurosci. 2022;16:984844, https://doi.org/10.3389/fnins.2022.984844 (2022)](https://doi.org/10.3389/fnins.2022.984844](https://doi.org/10.3389/fnins.2022.984844](https://doi.org/10.3389/fnins.2022.984844)

[GSK2656157 clinical development, https://doi.org/10.1016/j.ymthe.2021.05.014 (2021)](https://doi.org/10.1016/j.ymthe.2021.05.014](https://doi.org/10.1016/j.ymthe.2021.05.014](https://doi.org/10.1016/j.ymthe.2021.05.014)

[Sidrauski C et al. Pharmacological dimerization and blockade of the integrated stress response. Cell. 2015;162(2):446-460, https://doi.org/10.1016/j.cell.2015.06.044 (2015)](https://doi.org/10.1016/j.cell.2015.06.044](https://doi.org/10.1016/j.cell.2015.06.044](https://doi.org/10.1016/j.cell.2015.06.044)

Pathway Diagram

Mermaid diagram (expand to render)

Pathway Diagram

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

Mermaid diagram (expand to render)

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Related Entities

PERK

▸Metadataorigin_type: v1_polymorphic_backfill

slug	proteins-perk
kg_node_id	PERK
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-902e26cfa874
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-perk'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

25

Outgoing

44

0 supporting 0 contradicting 0 neutral

View full evidence profile →

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📗 Cite This Artifact

PERK Protein

PERK Protein

PERK Protein

Overview

Structure and Domains

Normal Function

Unfolded Protein Response

Integrated Stress Response

Physiological Roles

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Huntington's Disease

ALS and FTD

Prion Diseases

Therapeutic Targeting

PERK Inhibitors

ISRIB

Gene Therapy Approaches

Key Interactions

See Also

External Links

References

Pathway Diagram

Pathway Diagram

💬 Discussion