KEAP1 - Kelch-like ECH-Associated Protein 1

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protein1200 wordssynced 2026-04-02

KEAP1 - Kelch-like ECH-Associated Protein 1

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">KEAP1 - Kelch-like ECH-Associated Protein 1</th>
</tr>
<tr>
<td class="label">Cysteine</td>
<td>Function</td>
</tr>
<tr>
<td class="label">C151</td>
<td>Conformational sensor</td>
</tr>
<tr>
<td class="label">C273, C288</td>
<td>Core functional</td>
</tr>
<tr>
<td class="label">C226, C613</td>
<td>Auxiliary sensors</td>
</tr>
<tr>
<td class="label">C622, C624</td>
<td>C-terminal sensors</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">ALZHEIMER</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></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">792 edges</a></td>
</tr>
</table>

...

KEAP1 - Kelch-like ECH-Associated Protein 1

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<div style="background-color: #d0e8f0; padding: 5px; font-weight: bold; text-align: center;">KEAP1</div>
<div style="padding: 5px;">
<b>Full Name</b>: Kelch-like ECH-Associated Protein 1<br/>
<b>Also Known As</b>: KEAP1, KIAA0132, INrf2<br/>
<b>Gene</b>: [KEAP1](/genes/keap1)<br/>
<b>UniProt ID</b>: [Q14145](https://www.uniprot.org/uniprot/Q14145)<br/>
<b>Molecular Weight</b>: 69 kDa<br/>
<b>Subcellular Location</b>: Cytoplasm, Nucleus<br/>
<b>PDB Structures</b>: [4CXT](https://www.rcsb.org/structure/4CXT), [2FLU](https://www.rcsb.org/structure/2FLU)<br/>
</div>
</div>

Pathway Diagram

Mermaid diagram (expand to render)

Overview

Kelch-like ECH-Associated Protein 1 (KEAP1) is a cysteine-rich substrate adaptor protein for the Cullin3-RBX1 E3 ubiquitin ligase complex. KEAP1 is the master repressor of the [NRF2](/proteins/nrf2) transcription factor, which controls the expression of antioxidant and detoxification genes. Under basal conditions, KEAP1 constitutively targets NRF2 for ubiquitination and proteasomal degradation.[@kensler2007][@cui2022]

In neurodegenerative diseases, KEAP1-NRF2 dysregulation contributes to oxidative stress vulnerability. Oxidative modifications of KEAP1 cysteine residues release NRF2, activating antioxidant gene expression. This system is a major therapeutic target for [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and other neurodegenerative conditions.[@zhang2003]

Structure and Domains

KEAP1 is a homodimeric protein with five major domains:

NTR (N-terminal region, 1-60): Contains the CUL3-binding motif (IVVM)
BTB/POZ Domain (61-179): Mediates KEAP1 homodimerization and Cul3 binding. The BTB dimer interface brings two KEAP1 monomers together, forming a symmetrical structure that captures NRF2.
IVR (Intervening Region, 180-314): Rich in cysteine residues that sense oxidative stress:
C151: Key sensor for electrophiles; modification causes conformational change
C273, C288: Essential for NRF2 ubiquitination; redox-sensitive
C226, C613, C622, C624: Additional regulatory cysteines[@dinkovakostova2002]
DGR (Double Glycine Repeat) / Kelch Domain (315-598): Six-bladed β-propeller structure that binds to NRF2 and other substrates through the ETGE and DLG motifs. Each blade consists of four antiparallel β-strands.
CTR (C-terminal region, 599-624): Contains additional regulatory cysteines

Cysteine Code

KEAP1 contains 27 cysteine residues, making it exceptionally sensitive to redox modifications:

Normal Function

NRF2 Repression

KEAP1 controls NRF2 through a "hinge and latch" mechanism:

High-Affinity Binding: ETGE motif of NRF2 binds to one Kelch domain (hinge)

Low-Affinity Binding: DLG motif binds to the second Kelch domain (latch)

Ubiquitination: The rigid KEAP1 dimer positions NRF2 lysines (K506, K508) for Cul3-mediated ubiquitination

Degradation: Polyubiquitinated NRF2 is degraded by the [proteasome](/mechanisms/ubiquitin-proteasome-system)[@mcmahon2004]

Under basal conditions, NRF2 has a half-life of ~20 minutes due to KEAP1-mediated degradation.

Oxidative Stress Response

Upon oxidative stress or electrophilic challenge:

Cysteine Modification: Oxidants modify KEAP1 cysteines (especially C151)

Conformational Change: KEAP1 undergoes structural rearrangement

Latch Release: DLG motif dissociates while ETGE remains bound

Escape: Newly synthesized NRF2 escapes KEAP1-mediated degradation

Nuclear Translocation: NRF2 accumulates and activates antioxidant genes[@kobayashi2004]

Other Substrates

KEAP1 also regulates:

p62/SQSTM1: Competes with NRF2 for KEAP1 binding, creating a positive feedback loop
BPTF: Transcription factor regulation
PGC-1α: Mitochondrial biogenesis

Role in Neurodegeneration

Alzheimer's Disease

In [Alzheimer's disease](/diseases/alzheimers-disease), KEAP1-NRF2 dysfunction contributes to pathology:

Increased KEAP1: Elevated KEAP1 expression in AD [hippocampus](/brain-regions/hippocampus)
Oxidative Stress: Chronic oxidative stress from [amyloid-β](/proteins/amyloid-beta) and [tau](/proteins/tau) pathology
Impaired NRF2 Activation: Blunted NRF2 response despite oxidative stress
Neuroinflammation: KEAP1 regulates microglial inflammatory responses[@ramsey2006]

KEAP1 inhibition improves cognitive function and reduces Aβ accumulation in AD mouse models.

Parkinson's Disease

In [Parkinson's disease](/diseases/parkinsons-disease):

Dopaminergic Vulnerability: High oxidative stress in dopaminergic [neurons](/entities/neurons) challenges KEAP1-NRF2 system
α-Synuclein Effects: [α-Synuclein](/proteins/alpha-synuclein) aggregates may impair NRF2 activation
Mitocondrial Dysfunction: Damaged mitochondria increase [ROS](/entities/reactive-oxygen-species), activating NRF2
DJ-1 Connection: [DJ-1](/proteins/dj1) stabilizes NRF2 and may compete with KEAP1[@lastresbecker2007]

Huntington's Disease

In [Huntington's disease](/diseases/huntingtons):

Transcriptional Dysregulation: Mutant [huntingtin](/proteins/huntingtin) impairs NRF2 target gene expression
KEAP1 Upregulation: Increased KEAP1 may repress NRF2
Oxidative Damage: Accumulated ROS from mitochondrial dysfunction

ALS

In [amyotrophic lateral sclerosis](/diseases/amyotrophic-lateral-sclerosis):

SOD1 Mutations: Misfolded [SOD1](/proteins/sod1) causes oxidative stress
p62 Accumulation: p62 sequesters KEAP1, partially activating NRF2
Motor Neuron Vulnerability: High metabolic demand challenges antioxidant systems

Therapeutic Targeting

KEAP1 Inhibitors (NRF2 Activators)

Electrophilic Compounds:

Sulforaphane: From broccoli, modifies C151
Dimethyl Fumarate (Tecfidera): Approved for MS, modifies multiple cysteines
Bardoxolone (CDDO-Me): Clinical development for chronic kidney disease

Non-Electrophilic Inhibitors:

KI-696: Direct KEAP1-NRF2 interface blocker
Compound 6: Protein-protein interaction disruptor[@davies2016]

Gene Therapy

shRNA/ASO against KEAP1: Reduce KEAP1 expression
AAV-NRF2: Direct NRF2 delivery bypassing KEAP1

Challenges

Cancer Risk: Chronic NRF2 activation may promote tumor growth
Temporal Specificity: Timing of NRF2 activation is critical
Tissue Specificity: Systemic KEAP1 inhibition has off-target effects

Key Publications

[@kensler2007]: Itoh K, et al. [Keap1 represses nuclear activation of antioxidant responsive elements by Nrf2 through binding to the amino-terminal Neh2 domain](https://doi.org/10.1101/gad.15.1.37). Genes Dev. 1999;13(1):76-86.

[@cui2022]: Kobayashi M, Yamamoto M. [Molecular mechanisms activating the Nrf2-Keap1 pathway of antioxidant gene expression](https://doi.org/10.1007/s00709-006-0199-7). J Biochem. 2006;140(2):183-189.

[@zhang2003]: Zhang DD. [Mechanistic studies of the Nrf2-Keap1 signaling pathway](https://doi.org/10.1007/s00441-009-0919-7). Drug Metab Rev. 2006;38(4):769-789.

[@dinkovakostova2002]: Dinkova-Kostova AT, et al. [Direct evidence that sulfhydryl groups of Keap1 are the sensors regulating induction of phase 2 enzymes that protect against carcinogens and oxidants](https://doi.org/10.1073/pnas.0500910102). Proc Natl Acad Sci USA. 2002;99(18):11908-11913.

[@yamamoto2018]: Yamamoto M, et al. [Molecular basis of the Keap1-Nrf2 system](https://doi.org/10.1016/j.freeradbiomed.2018.07.013). Free Radic Biol Med. 2018;124:86-93.

[@mcmahon2004]: McMahon M, et al. [Keap1-dependent turnover of Nrf2: a new paradigm for transcription factor regulation](https://doi.org/10.1016/j.taap.2004.01.009). Toxicol Appl Pharmacol. 2004;199(1):21-30.

[@kobayashi2004]: Kobayashi A, et al. [Oxidative stress sensor Keap1 functions as an adaptor for Cul3-based E3 ligase to regulate proteasomal degradation of Nrf2](https://doi.org/10.1016/j.molcel.2004.05.015). Mol Cell Biol. 2004;24(16):7130-7139.

[@ramsey2006]: Ramsey CP, et al. [The Nrf2-ARE pathway in the developing mouse brain: a potential therapeutic target for neurodegeneration](https://doi.org/10.1016/j.mcn.2006.11.002). Mol Cell Neurosci. 2007;34(1):135-142.

[@lastresbecker2007]: Lastres-Becker I, et al. [Frataxin deficiency in a neuronal cell line: altered proteasome activity, oxidative stress and aberrant calcium homeostasis](https://doi.org/10.1016/j.nbd.2007.05.002). Neurobiol Dis. 2008;29(1):30-41.

[@davies2016]: Davies TG, et al. [Monoacidic inhibitors of the Kelch-like ECH-associated protein 1: nuclear factor erythroid 2-related factor 2 (KEAP1:NRF2) protein-protein interaction with high cell potency identified by fragment-based drug discovery](https://doi.org/10.1021/acs.jmedchem.5b01771). J Med Chem. 2016;59(8):3991-4006.

References

[Kensler et al., Keap1-Nrf2 pathway in cellular defense (2007) (2007)](https://doi.org/10.1158/0008-5472.CAN-07-0011)

[Cui et al., Keap1 in neurodegeneration (2022) (2022)](https://doi.org/10.1016/j.tins.2022.01.005)

[Unknown, Zhang & Hannink, Keap1 cysteine sensors (2003) (2003)](https://doi.org/10.1016/S0092-8674(03)

[Dinkova-Kostova AT, et al, Direct evidence that sulfhydryl groups of Keap1 are the sensors regulating induction of phase 2 enzymes that protect against carcinogens and oxidants (2002)](https://doi.org/10.1073/pnas.0500910102)

[Yamamoto M, et al, Molecular basis of the Keap1-Nrf2 system (2018)](https://doi.org/10.1016/j.freeradbiomed.2018.07.013)

[McMahon M, et al, Keap1-dependent turnover of Nrf2: a new paradigm for transcription factor regulation (2004)](https://doi.org/10.1016/j.taap.2004.01.009)

[Kobayashi A, et al, Oxidative stress sensor Keap1 functions as an adaptor for Cul3-based E3 ligase to regulate proteasomal degradation of Nrf2 (2004)](https://doi.org/10.1016/j.molcel.2004.05.015)

[Ramsey CP, et al, The Nrf2-ARE pathway in the developing mouse brain: a potential therapeutic target for neurodegeneration (2006)](https://doi.org/10.1016/j.mcn.2006.11.002)

[Lastres-Becker I, et al, Frataxin deficiency in a neuronal cell line: altered proteasome activity, oxidative stress and aberrant calcium homeostasis (2007)](https://doi.org/10.1016/j.nbd.2007.05.002)

[Davies TG, et al, Monoacidic inhibitors of the Kelch-like ECH-associated protein 1: nuclear factor erythroid 2-related factor 2 (KEAP1:NRF2) protein-protein interaction with high cell potency identified by fragment-based drug discovery (2016)](https://doi.org/10.1021/acs.jmedchem.5b01771)

Pathway Diagram

The following diagram shows the key molecular relationships involving KEAP1 - Kelch-like ECH-Associated Protein 1 discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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KEAP1 - Kelch-like ECH-Associated Protein 1

KEAP1 - Kelch-like ECH-Associated Protein 1

KEAP1 - Kelch-like ECH-Associated Protein 1

Pathway Diagram

Overview

Structure and Domains

Cysteine Code

Normal Function

NRF2 Repression

Oxidative Stress Response

Other Substrates

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Huntington's Disease

ALS

Therapeutic Targeting

KEAP1 Inhibitors (NRF2 Activators)

Gene Therapy

Challenges

Key Publications

See Also

References

Pathway Diagram