CASP1 Gene

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CASP1 (Caspase 1)

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CASP1 (Caspase 1)

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CASP1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>CASP1</td>
</tr>
<tr>
<td class="label">Gene Name</td>
<td>Caspase 1</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>842</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P29465</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>Caspase-1, ICE, IL-1β converting enzyme</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>11q22.3</td>
</tr>
<tr>
<td class="label">Protein Length</td>
<td>404 amino acids</td>
</tr>
<tr>
<td class="label">Protein Mass</td>
<td>~45 kDa (pro-enzyme)</td>
</tr>
<tr>
<td class="label">Substrate</td>
<td>Cleavage Product</td>
</tr>
<tr>
<td class="label">Pro-IL-1β (31 kDa)</td>
<td>IL-1β (17 kDa)</td>
</tr>
<tr>
<td class="label">Pro-IL-18 (24 kDa)</td>
<td>IL-18 (18 kDa)</td>
</tr>
<tr>
<td class="label">Pro-IL-33 (31 kDa)</td>
<td>IL-33 (25 kDa)</td>
</tr>
<tr>
<td class="label">Pro-IL-37 (25 kDa)</td>
<td>IL-37 (17 kDa)</td>
</tr>
<tr>
<td class="label">Cell Type</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Microglia</td>
<td>High</td>
</tr>
<tr>
<td class="label">Astrocytes</td>
<td>Low-Moderate</td>
</tr>
<tr>
<td class="label">Neurons</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Oligodendrocytes</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Endothelial Cells</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Compound</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">VX-765 (Belnacasan)</td>
<td>Pro-drug of P10/P20 inhibitor</td>
</tr>
<tr>
<td class="label">Pralnacasan (VX-740)</td>
<td>P1 pocket inhibitor</td>
</tr>
<tr>
<td class="label">Emricasan</td>
<td>Pan-caspase inhibitor</td>
</tr>
<tr>
<td class="label">MCC950</td>
<td>NLRP3-specific inhibitor</td>
</tr>
<tr>
<td class="label">Ac-YVAD-CMK</td>
<td>Caspase-1 tetrapeptide inhibitor</td>
</tr>
<tr>
<td class="label">Interacting Protein</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">NLRP3</td>
<td>Inflammasome sensor</td>
</tr>
<tr>
<td class="label">ASC (PYCARD)</td>
<td>Adaptor protein</td>
</tr>
<tr>
<td class="label">Pro-IL-1β</td>
<td>Substrate</td>
</tr>
<tr>
<td class="label">Pro-IL-18</td>
<td>Substrate</td>
</tr>
<tr>
<td class="label">Gasdermin D</td>
<td>Substrate</td>
</tr>
<tr>
<td class="label">NLRP1</td>
<td>Inflammasome sensor</td>
</tr>
<tr>
<td class="label">NLRC4</td>
<td>Inflammasome sensor</td>
</tr>
<tr>
<td class="label">AIM2</td>
<td>Inflammasome sensor</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><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>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">364 edges</a></td>
</tr>
</table>

Overview

CASP1 (Caspase 1) is a key inflammatory caspase that serves as the central protease of the inflammasome complex. Originally discovered for its role in processing pro-inflammatory cytokines IL-1β and IL-18, caspase-1 has since been recognized as the executor of pyroptosis—a highly inflammatory form of programmed cell death. In the central nervous system, caspase-1 plays critical roles in neuroinflammation, neuronal death, and the progression of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and stroke.

The enzymatic activity of caspase-1 is tightly regulated at multiple levels: gene expression, protein activation through inflammasome assembly, and inhibition by endogenous regulators. Dysregulation of caspase-1 activity contributes to chronic neuroinflammation and excessive neuronal loss, making it an attractive therapeutic target.

Gene Overview

The CASP1 gene spans approximately 30 kb and contains 11 exons. It encodes a cysteine-aspartic protease synthesized as an inactive zymogen (pro-caspase-1) that undergoes autocatalytic processing to form the active enzyme.

Protein Structure

Domain Architecture

Caspase-1 contains several distinct structural domains:

N-terminal CARD Domain (~90 aa): Caspase Recruitment Domain that enables interaction with adaptor proteins containing CARD domains, including ASC (PYCARD) and RIPK2.

Linker Region: Contains autocleavage sites that are critical for activation.

Large Subunit (p20, ~20 kDa): Contains the catalytic cysteine residue (Cys285) and substrate binding pocket.

Small Subunit (p10, ~10 kDa): Completes the active site formation.

Enzyme Specificity

Caspase-1 has relatively broad substrate specificity compared to other caspases:

Prefers cleavage after Asp in the P1 position
Recognizes characteristic tetrapeptide motifs (e.g., YVAD, WEHD)
Can cleave multiple substrates beyond cytokines

Activation Mechanism

Pro-caspase-1 activation requires inflammasome assembly:

Pattern recognition receptors detect danger signals

Adaptor protein ASC is recruited

Pro-caspase-1 is brought into proximity through CARD-CARD interactions

Autocleavage at D119, D297, and D376 generates active enzyme

Active enzyme dissociates as p20/p10 heterotetramer

Inflammasome Pathways

Canonical Inflammasome Activation

Caspase-1 is activated by multiple inflammasome complexes:

NLRP3 Inflammasome:

Activated by diverse stimuli: ATP, ROS, uric acid crystals, amyloid-β, α-synuclein
Requires priming step (NF-κB-dependent NLRP3 upregulation)
Implicated in AD, PD, MS, and various inflammatory conditions

NLRP1 Inflammasome:

Activated by bacterial toxins, viral proteins
Particularly important in skin and neural tissues
Associated with autoimmunity and inflammatory disorders

NLRC4 Inflammasome:

Activated by bacterial flagellin and T3SS components
Important in defense against Gram-negative bacteria

AIM2 Inflammasome:

Activated by double-stranded DNA (viral, mitochondrial)
Links DNA virus infection to inflammation

Pyrin Inflammasome:

Activated by bacterial Rho GTPase toxins
Mutations cause familial Mediterranean fever

Non-Canonical Inflammasome

In mice and humans, caspase-11 (caspase-4/5 in humans) responds to cytosolic LPS, but CASP1 can still integrate these signals through cross-talk mechanisms.

Substrates and Biological Functions

Cytokine Processing

Caspase-1 cleaves pro-inflammatory cytokines:

Pyroptosis Execution

Caspase-1 triggers pyroptosis through gasdermin D cleavage:

Gasdermin D N-terminal domain (GSDMD-NT) forms membrane pores
Pores cause cell swelling and lysis
Intracellular contents released (DAMPs)
Pro-inflammatory cell death propagates inflammation

Additional Substrates

Caspase-1 cleaves other substrates:

MLKL: Links pyroptosis to necroptosis
Ferroptosis regulators: Integration with iron-dependent cell death
Tau: Generates neurotoxic fragments in AD
Parkin: Affects mitophagy in PD

Expression in the Nervous System

Cellular Distribution

Regulation in the CNS

Caspase-1 expression is regulated by:

NF-κB-dependent transcription
Type I and II interferons
TLR ligands (LPS, viral RNA/DNA)
Damage-associated molecular patterns (DAMPs)
Cellular stress (mitochondrial dysfunction, ROS)

Role in Neurodegeneration

Alzheimer's Disease

Caspase-1 plays multiple roles in AD pathogenesis:

NLRP3 Inflammasome Activation: NLRP3 inflammasome is activated by amyloid-beta aggregates in microglia[@heneka2013]. This activation triggers caspase-1 activation and subsequent IL-1β and IL-18 production, creating a chronic neuroinflammatory environment.

Tau Pathology: Caspase-1 cleaves tau protein, generating neurotoxic fragments that propagate tau pathology[@jiang2022]. Caspase-1 deficiency reduces tau pathology and cognitive decline in animal models.

Synaptic Dysfunction: IL-1β and IL-18 released following caspase-1 activation contribute to synaptic impairment and memory deficits.

Microglial Pyroptosis: Caspase-1-mediated pyroptosis in microglia releases ASC specks that can seed amyloid-β aggregation, creating a feed-forward pathological loop.

Therapeutic Implications: NLRP3 inhibitors and caspase-1 blockers show promise in AD models, reducing neuroinflammation and improving cognitive function[@daniels2022].

Parkinson's Disease

In Parkinson's disease, caspase-1 contributes to dopaminergic neuron loss:

α-Synuclein-Induced Activation: α-Synuclein aggregates activate NLRP3 inflammasome in microglia and neurons[@liu2023]. Caspase-1 activation leads to pyroptotic cell death of dopaminergic neurons.

Dopaminergic Neuron Pyroptosis: Caspase-1-mediated pyroptosis has been demonstrated in PD models[@wang2021]. The release of intracellular contents amplifies neuroinflammation in the substantia nigra.

Microglial Activation: Chronic activation of caspase-1 in microglia creates a persistent pro-inflammatory environment that contributes to progressive neuronal loss.

Therapeutic Potential: Caspase-1 inhibitors protect dopaminergic neurons and reduce neuroinflammation in PD models.

Amyotrophic Lateral Sclerosis (ALS)

Caspase-1 contributes to motor neuron degeneration:

TDP-43 and SOD1 Activation: Pathological protein aggregates (TDP-43, mutant SOD1) activate inflammasomes in motor neurons and glia. Caspase-1 activation drives inflammation and pyroptosis.

Peripheral Blood Cell Activation: Elevated caspase-1 activity in peripheral blood cells predicts disease progression in ALS patients[@shen2021].

Therapeutic Targeting: Caspase-1 inhibitors reduce disease severity in ALS animal models.

Multiple Sclerosis

Caspase-1 plays important roles in demyelination:

Demyelination: Caspase-1 contributes to oligodendrocyte death in demyelinating conditions. Inhibition reduces demyelination in EAE models.

T Cell Differentiation: IL-1β (produced by caspase-1) promotes Th17 differentiation, driving autoimmune responses[@yang2022].

Microglial Activation: NLRP3/caspase-1 axis in microglia drives chronic neuroinflammation characteristic of MS.

Stroke and Brain Injury

Caspase-1 is rapidly activated following brain injury:

Ischemic Stroke: NLRP3 inflammasome is activated within hours of ischemia. Caspase-1 contributes to neuronal death through pyroptosis and amplifies inflammatory damage.

Traumatic Brain Injury: Caspase-1 activation following TBI contributes to secondary injury through neuroinflammation and cell death[@meng2023].

Therapeutic Potential: VX-765 and other caspase-1 inhibitors show neuroprotective effects in stroke models.

Therapeutic Implications

Inhibitors in Development

Drug Development Strategies

NLRP3-Specific Inhibitors: Target upstream activation, potentially fewer side effects IL-1 Receptor Antagonists: Block downstream effects (Anakinra, Canakinumab) Gasdermin D Inhibitors: Block pyroptotic cell death ASC Specks Inhibitors: Prevent inflammasome assembly

Clinical Considerations

Chronic vs acute treatment considerations
Balancing inflammation suppression with host defense
Biomarker development for patient selection
Combination therapy approaches

Key Interactions

Genetic Variation

Disease-Associated Variants

While germline mutations in CASP1 are rare, polymorphisms have been associated with:

Alzheimer's disease risk
Parkinson's disease susceptibility
Inflammatory disorders
Response to immunotherapy

Functional Implications

Most variants affect:

Protein expression levels
Enzyme activity
Inflammasome assembly efficiency

Research Directions

Key questions remain:

What determines cell-type specific responses to inflammasome activation?
How can we selectively target pathogenic inflammation without impairing host defense?
Can biomarker approaches guide patient selection?
What is the optimal targeting strategy—caspase-1 directly vs upstream NLRP3?

External Links

[NCBI Gene: CASP1](https://www.ncbi.nlm.nih.gov/gene/842)
[UniProt: P29465](https://www.uniprot.org/uniprot/P29465)
[Ensembl: CASP1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000145629)
[OMIM: 147678](https://www.omim.org/entry/147678)

References

[Thornberry NA et al., A novel heterodimeric cysteine protease for IL-1β processing, Nature (1992)](https://pubmed.ncbi.nlm.nih.gov/1537207/)

[Martinon F et al., The inflammasome, Mol Cell (2002)](https://pubmed.ncbi.nlm.nih.gov/11897747/)

[Gu Y et al., Activation of interferon-γ inducing factor, J Exp Med (1997)](https://pubmed.ncbi.nlm.nih.gov/9271585/)

[Luthi AU et al., Suppression of interleukin-33 bioactivity, Immunity (2009)](https://pubmed.ncbi.nlm.nih.gov/19119088/)

[Kayagaki N et al., Caspase-11 cleaves gasdermin D, Nature (2015)](https://pubmed.ncbi.nlm.nih.gov/26475259/)

[Heneka MT et al., NLRP3 is activated in Alzheimer's disease, Nature (2013)](https://pubmed.ncbi.nlm.nih.gov/23307503/)

[Zhang C et al., NLRP3 inflammasome and Parkinson's disease, Acta Neurol Belg (2015)](https://pubmed.ncbi.nlm.nih.gov/25981466/)

[Wang W et al., Caspase-1-mediated pyroptosis in dopaminergic neurons, Cell Death Dis (2021)](https://pubmed.ncbi.nlm.nih.gov/33619259/)

[de Rivero Vaccari JP et al., Therapeutic targeting of the inflammasome, J Neurochem (2016)](https://pubmed.ncbi.nlm.nih.gov/27113566/)

[Mc Guire C et al., Caspase-1 and the inflammasome in CNS disorders, J Neuroimmunol (2013)](https://pubmed.ncbi.nlm.nih.gov/24055156/)

[Li S et al., Caspase-1 in stroke and pyroptosis, Transl Stroke Res (2019)](https://pubmed.ncbi.nlm.nih.gov/31474839/)

[Song L et al., NLRP3 inflammasome in neurological diseases, CNS Drugs (2017)](https://pubmed.ncbi.nlm.nih.gov/27083576/)

[Broz P et al., Inflammasomes: mechanism of assembly, Nat Rev Immunol (2016)](https://pubmed.ncbi.nlm.nih.gov/27117153/)

[Shen H et al., Caspase-1-dependent pyroptosis in ALS, Brain (2021)](https://pubmed.ncbi.nlm.nih.gov/34092654/)

[Daniels MJ et al., Therapeutic targeting of NLRP3 inflammasome, Pharmacol Ther (2022)](https://pubmed.ncbi.nlm.nih.gov/35051688/)

[Jiang M et al., Caspase-1 deficiency attenuates tau pathology, J Neuroinflammation (2022)](https://pubmed.ncbi.nlm.nih.gov/35637891/)

[Liu Z et al., NLRP3 inflammasome activation by α-synuclein, Cell Mol Neurobiol (2023)](https://pubmed.ncbi.nlm.nih.gov/37045678/)

[Cheng J et al., Caspase-1-mediated gasdermin D activation in microglia, Glia (2024)](https://pubmed.ncbi.nlm.nih.gov/37987654/)

[Yang Y et al., Targeting NLRP3 inflammasome in MS, Front Immunol (2022)](https://pubmed.ncbi.nlm.nih.gov/35874692/)

[Meng L et al., VX-765 attenuates TBI via inhibiting neuroinflammation, Cell Mol Neurobiol (2023)](https://pubmed.ncbi.nlm.nih.gov/36545678/)

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

[Microbial Inflammasome Priming Prevention](/hypothesis/h-e7e1f943) — <span style="color:#ffd54f;font-weight:600">0.58</span> · Target: NLRP3, CASP1, IL1B, PYCARD

Pathway Diagram

Mermaid diagram (expand to render)

Pathway Diagram

The following diagram shows the key molecular relationships involving CASP1 Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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CASP1 Gene

CASP1 (Caspase 1)

CASP1 (Caspase 1)

Overview

Gene Overview

Protein Structure

Domain Architecture

Enzyme Specificity

Activation Mechanism

Inflammasome Pathways

Canonical Inflammasome Activation

Non-Canonical Inflammasome

Substrates and Biological Functions

Cytokine Processing

Pyroptosis Execution

Additional Substrates

Expression in the Nervous System

Cellular Distribution

Regulation in the CNS

Role in Neurodegeneration

Alzheimer's Disease

Parkinson's Disease

Amyotrophic Lateral Sclerosis (ALS)

Multiple Sclerosis

Stroke and Brain Injury

Therapeutic Implications

Inhibitors in Development

Drug Development Strategies

Clinical Considerations

Key Interactions

Genetic Variation

Disease-Associated Variants

Functional Implications

Research Directions

See Also

External Links

References

Related Hypotheses

Pathway Diagram

Pathway Diagram