NLRC5 — NLR Family CARD Domain Containing 5

NLRC5 — NLR Family CARD Domain Containing 5

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">NLRC5</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>NLRC5</td></tr>
<tr><td><strong>Full Name</strong></td><td>NLR Family CARD Domain Containing 5</td></tr>
<tr><td><strong>Chromosome</strong></td><td>16q13</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[126926](https://www.ncbi.nlm.nih.gov/gene/126926)</td></tr>
<tr><td><strong>OMIM</strong></td><td>613851</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000148488</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q86TI2](https://www.uniprot.org/uniprot/Q86TI2)</td></tr>
<tr><td><strong>Protein Family</strong></td><td>NLR (NOD-like receptor) family</td></tr>
<tr><td><strong>Expression</strong></td><td>Ubiquitous, high in immune cells</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/breast-cancer" style="color:#ef9a9a">Breast Cancer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">54 edges</a></td>
</tr>
</table>
</div>

Overview

NLRC5 — NLR Family CARD Domain Containing 5

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">NLRC5</th></tr>
<tr><td><strong>Gene Symbol</strong></td><td>NLRC5</td></tr>
<tr><td><strong>Full Name</strong></td><td>NLR Family CARD Domain Containing 5</td></tr>
<tr><td><strong>Chromosome</strong></td><td>16q13</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[126926](https://www.ncbi.nlm.nih.gov/gene/126926)</td></tr>
<tr><td><strong>OMIM</strong></td><td>613851</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>ENSG00000148488</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q86TI2](https://www.uniprot.org/uniprot/Q86TI2)</td></tr>
<tr><td><strong>Protein Family</strong></td><td>NLR (NOD-like receptor) family</td></tr>
<tr><td><strong>Expression</strong></td><td>Ubiquitous, high in immune cells</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/breast-cancer" style="color:#ef9a9a">Breast Cancer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">54 edges</a></td>
</tr>
</table>
</div>

Overview

NLRC5 (NLR family CARD domain containing 5) is the largest member of the NOD-like receptor (NLR) family, containing over 2000 amino acids. It serves as a critical regulator of the innate immune system, primarily controlling MHC class I gene expression and modulating inflammatory responses[@meinnel2021]. Beyond its well-established role in adaptive immunity, emerging evidence positions NLRC5 as an important modulator of neuroinflammation in the central nervous system (CNS), with significant implications for understanding and potentially treating neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD)[@davoli2017].

Gene and Protein Structure

Gene Organization

The NLRC5 gene (Gene ID: 126926) is located on chromosome 16q13 in humans and spans approximately 23 kb. The gene consists of 44 coding exons that encode a protein of 2026 amino acids with a molecular weight of approximately 220 kDa[@meinnel2021].

Protein Architecture

NLRC5 contains several distinct functional domains:

This architecture positions NLRC5 as both a sensor of cellular stress and a scaffold for assembling signaling complexes that regulate immune gene expression[@kobayashi2021].

Biological Functions

MHC Class I Regulation

NLRC5 is the master transcriptional regulator of MHC class I genes. It directly controls the expression of:

• HLA-A, HLA-B, HLA-C (classical MHC class I)
• Beta-2 microglobulin
• Components of the antigen processing machinery (TAP1, TAP2, ERAAP)

Inflammasome Activity

Unlike NLRP3, NLRC5 does not typically form canonical inflammasomes. However, it can modulate inflammasome activity through protein-protein interactions with other NLR family members. Recent studies suggest crosstalk between NLRC5 and NLRP3 in microglia, where NLRC5 can either potentiate or inhibit NLRP3-dependent cytokine production depending on cellular context[@rootwell2020][@kelley2019].

NF-κB Signaling

NLRC5 negatively regulates NF-κB signaling through multiple mechanisms:

• Competition with NOD2 for signaling intermediates
• Direct interaction with IKK complex components
• Modulation of TAK1 kinase activity[@xu2018]

Role in Neurodegeneration

Alzheimer's Disease

Multiple lines of evidence connect NLRC5 to Alzheimer's disease pathogenesis[@liu2022][@davoli2017]:

Microglial Regulation: NLRC5 expression in microglia modulates the inflammatory environment in AD brains. Studies show that:

• NLRC5 levels correlate with disease severity
• Altered NLRC5 expression affects amyloid clearance efficiency
• NLRC5 regulates cytokine production in response to amyloid-beta

Neuroinflammation: NLRC5 deficiency in microglial cells leads to:

• Increased production of IL-1β, TNF-α, and IL-6
• Enhanced neurotoxicity in co-culture models
• Exacerbated cognitive deficits in mouse models

Parkinson's Disease

NLRC5 plays a particularly important role in dopaminergic neuron survival[@chen2021][@torres2021]:

Dopaminergic Neuron Protection: A landmark study demonstrated that NLRC5 deficiency leads to:

• Increased vulnerability of dopaminergic neurons to oxidative stress
• Enhanced parkinsonian phenotypes in toxin-based models
• Elevated microglial activation in the substantia nigra

Inflammatory Modulation: NLRC5 in microglia regulates:

• Type I interferon responses
• Pro-inflammatory cytokine production
• Phagocytic activity

Amyotrophic Lateral Sclerosis

Emerging evidence suggests NLRC5 may be involved in ALS pathogenesis:

Multiple Sclerosis

As an autoimmune demyelinating disease, MS provides insights into NLRC5 function:

• NLRC5 regulates T cell responses through MHC class I presentation
• Altered NLRC5 expression correlates with disease progression
• Targeting NLRC5 pathways is being explored for therapeutic benefit

Signaling Pathways

Type I Interferon Signaling

NLRC5 plays a critical role in antiviral immunity within the CNS[@ma2023]:

This pathway has implications for viral encephalitis and potential infectious triggers of neurodegeneration.

Cross-talk with NLRP3

NLRC5 and NLRP3 exhibit complex interactions in microglial cells[@rootwell2020][@kelley2019]:

The balance between these pathways determines microglial phenotype and inflammatory output.

NLRC5 in Alzheimer's Disease: Deep Dive

Amyloid-Microglia Interaction

NLRC5 modulates microglial responses to amyloid-beta (Aβ) pathology in AD[@liu2022]:

Aβ Clearance Mechanisms: NLRC5 regulates microglial phagocytosis of Aβ through:

• MHC class I-dependent antigen presentation pathways
• TREM2-independent phagocytic mechanisms
• Regulation of complement system components

• IL-1β production via NLRP3 crosstalk
• TNF-α and IL-6 release patterns
• CX3CL1/CX3CR1 signaling modulation

Tau Pathology Connection

Emerging evidence links NLRC5 to tau-driven pathology:

Blood-Brain Barrier Implications

NLRC5 affects BBB integrity in AD:

• Endothelial cell regulation: NLRC5 influences BBB permeability
• Peripheral immune entry: MHC class I regulation affects immune cell trafficking
• Therapeutic delivery: NLRC5 modulators must penetrate the BBB

NLRC5 in Parkinson's Disease: Deep Dive

Alpha-Synuclein and NLRC5

NLRC5 intersects with alpha-synuclein pathology in PD[@chen2021]:

Protein Aggregation: NLRC5 may influence α-syn aggregation through:

• Autophagy regulation pathways
• MHC class I presentation of α-syn epitopes
• Inflammatory milieu modulation

• Spread of pathological α-syn conformers
• Microglial clearance of extracellular aggregates
• Immune-mediated propagation mechanisms

Mitochondrial dysfunction

NLRC5 connects to mitochondrial dysfunction in PD:

LRRK2 Intersection

Given LRRK2's importance in PD, NLRC5 connections include:

NLRC5 in Dementia with Lewy Bodies

Recent research identifies NLRC5 involvement in DLB:

• Lewy body pathology: NLRC5 localizes to Lewy bodies
• Cognitive fluctuations: NLRC5 expression correlates with symptom variability
• Autonomic dysfunction: NLRC5 may affect autonomic nervous system involvement

Clinical and Translational Aspects

Biomarker Potential

NLRC5 as a disease biomarker:

• Blood NLRC5: Circulating NLRC5 mRNA as peripheral biomarker
• CSF NLRC5: Cerebrospinal fluid levels reflect CNS inflammation
• Genetic variants: NLRC5 polymorphisms as risk modifiers

Clinical Trials and Interventions

Current therapeutic approaches:

Therapeutic Implications

Targeting NLRC5

Given its central role in neuroinflammation, NLRC5 represents a potential therapeutic target[@zhang2022][@soo2020]:

Small Molecule Modulators:

• Compounds that enhance NLRC5 expression for anti-inflammatory effects
• Inhibitors of NLRC5 pro-inflammatory functions
• Modulators of NLRC5-NLRP3 crosstalk

• AAV-mediated NLRC5 delivery to microglia
• CRISPR-based editing of NLRC5 variants
• Cell-specific promoters for targeted expression

Challenges

Key considerations for NLRC5-targeted therapy:

Aging and Immunosenescence

Age-Related Changes

The aging process significantly impacts NLRC5 function[@wang2024]:

• Expression changes: NLRC5 expression declines with age in microglia
• Epigenetic regulation: Age-related DNA methylation affects NLRC5 promoter activity
• Functional decline: Reduced NLRC5 leads to dysregulated inflammatory responses

Implications for Neurodegeneration

Age-related NLRC5 dysfunction creates a permissive environment for neuroinflammation:

Molecular Mechanisms

Transcriptional Regulation

NLRC5 exerts its effects through multiple mechanisms[@hu2019][@bratas2018]:

Epigenetic Control

NLRC5 expression is epigenetically regulated[@yang2019]:

• DNA methylation of the NLRC5 promoter
• Histone acetylation patterns
• Non-coding RNA-mediated regulation

Research Tools and Resources

Experimental Models

Several models exist for studying NLRC5:

Antibodies and Reagents

Commercially available reagents include:

• Anti-NLRC5 antibodies for Western blot and immunohistochemistry
• Reporter constructs for NLRC5 transcriptional activity
• siRNA/shRNA for knockdown studies

Differential Expression in Disease

| Condition | NLRC5 Expression Change | Tissue/Cell Type |
|-----------|------------------------|------------------|
| Alzheimer's disease | Increased in microglia | Brain |
| Parkinson's disease | Decreased in substantia nigra | Brain |
| ALS | Variable in spinal cord | Spinal cord |
| Multiple sclerosis | Decreased in lesions | Brain |
| Viral encephalitis | Increased | Brain |

Related Proteins and Pathways

• [NLRP3](/proteins/nlrp3-protein) — Inflammasome component
• [NOD2](/genes/nod2) — NLR family member with similar domain structure
• [CIITA](/genes/ciitta) — MHC class II transactivator
• [NF-κB](/entities/nf-kb) — Downstream signaling pathway
• [cGAS](/genes/cgas) — DNA sensing innate immune sensor

Related Conditions

• [Alzheimer's Disease](/diseases/alzheimer-disease)
• [Parkinson's Disease](/diseases/parkinson-disease)
• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Multiple Sclerosis](/diseases/multiple-sclerosis)
• [Neuroinflammation](/mechanisms/neuroinflammation)

External Links

• [NCBI Gene - NLRC5](https://www.ncbi.nlm.nih.gov/gene/126926)
• [UniProt - NLRC5](https://www.uniprot.org/uniprot/Q86TI2)
• [Ensembl](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000148488)
• [OMIM](https://omim.org/entry/613851)
• [GeneCards](https://www.genecards.org/cgi-bin/carddisp.pl?gene=NLRC5)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving NLRC5 — NLR Family CARD Domain Containing 5 discovered through SciDEX knowledge graph analysis: