CLEC7A / Dectin-1 Protein

CLEC7A / Dectin-1 Protein

Overview

CLEC7A (Dectin-1) is a type II transmembrane C-type lectin receptor (CLR) expressed primarily on [microglia](/cell-types/microglia) and other myeloid cells. Dectin-1 is the defining surface marker of disease-associated [microglia](/cell-types/microglia-neuroinflammation) (DAM) — a protective microglial activation state discovered in [Alzheimer's disease](/diseases/alzheimers-disease) that is dependent on [TREM2](/proteins/trem2-protein) signaling. CLEC7A activates SYK kinase-dependent phagocytic and inflammatory programs through its hemITAM signaling motif.

CLEC7A / Dectin-1 Protein

Overview

CLEC7A (Dectin-1) is a type II transmembrane C-type lectin receptor (CLR) expressed primarily on [microglia](/cell-types/microglia) and other myeloid cells. Dectin-1 is the defining surface marker of disease-associated [microglia](/cell-types/microglia-neuroinflammation) (DAM) — a protective microglial activation state discovered in [Alzheimer's disease](/diseases/alzheimers-disease) that is dependent on [TREM2](/proteins/trem2-protein) signaling. CLEC7A activates SYK kinase-dependent phagocytic and inflammatory programs through its hemITAM signaling motif.

<div class="infobox infobox-protein"> [@brown2006]
<div class="infobox-header">CLEC7A / Dectin-1 Protein</div> [@krasemann2017]
<table> [@zhou2020]
<tr><td class="infobox-label">Protein Name</td><td>C-type Lectin Domain Family 7 Member A (Dectin-1)</td></tr> [@safaiyan2021]
<tr><td class="infobox-label">Gene</td><td>[CLEC7A](/genes/clec7a)</td></tr> [@goodridge2011]
<tr><td class="infobox-label">UniProt ID</td><td>[Q9BXN2](https://www.uniprot.org/uniprot/Q9BXN2)</td></tr> [@deczkowska2018]
<tr><td class="infobox-label">Molecular Weight</td><td>~28 kDa</td></tr> [@shah2021]
<tr><td class="infobox-label">Subcellular Localization</td><td>Plasma membrane (type II orientation)</td></tr>
<tr><td class="infobox-label">Protein Family</td><td>C-type lectin receptors (CLRs), Group V NK cell receptors</td></tr>
<tr><td class="infobox-label">Associated Diseases</td><td>[Alzheimer's disease](/diseases/alzheimers-disease), [Multiple Sclerosis](/diseases/multiple-sclerosis), [ALS](/diseases/amyotrophic-lateral-sclerosis)</td></tr>
</table>
</div>

Structure

CLEC7A is a 247 amino acid type II transmembrane glycoprotein:

Domain Architecture

• Cytoplasmic tail (aa 1–44): Contains a hemITAM motif (YxxxL) at Tyr-15 that recruits [SYK](/genes/syk) kinase upon phosphorylation. Unlike classical ITAM motifs (which have two YxxL sequences), the hemITAM is sufficient for SYK recruitment through receptor dimerization
• Transmembrane domain (aa 45–66): Single-pass type II orientation (N-terminus intracellular, C-terminus extracellular)
• Stalk region (aa 67–117): Flexible linker; contains an N-linked glycosylation site. The stalk enables dimerization, which is required for full signaling capacity
• C-type lectin-like domain (CTLD) (aa 118–247): Binds beta-1,3-glucan ligands. Despite being classified as a C-type lectin, Dectin-1 binds ligands in a calcium-independent manner. The CTLD adopts a compact fold with two alpha-helices, two antiparallel beta-sheets, and a ligand-binding groove

Oligomerization

Splice Variants

• Isoform A (full-length): Contains the stalk region; forms higher-order oligomers
• Isoform B (Δ stalk): Lacks the stalk; remains monomeric but retains ligand binding and some signaling capacity

Normal Function

Pattern Recognition

• Damage-associated molecular patterns (DAMPs): Released from dying [neurons](/entities/neurons), including oxidized lipids and carbohydrates
• Myelin debris: During demyelination, exposed carbohydrate structures on damaged myelin are recognized by Dectin-1
• Amyloid-associated lipids: Modified lipoproteins in the plaque microenvironment

Signaling Cascade

• CARD9/BCL10/MALT1 → [NF-κB](/genes/nfkb1) → pro-inflammatory cytokines (IL-1β, TNF, IL-6)
• PLCγ2 ([PLCG2](/genes/plcg2)) → NFAT → immune gene transcription
• PI3K/AKT → cell survival and metabolic reprogramming
• Raf-1 → noncanonical [NF-κB](/entities/nf-kb) → anti-inflammatory cytokine production (IL-10)
• NADPH oxidase ([NOX2](/genes/nox2)) → [ROS](/entities/reactive-oxygen-species) production for pathogen killing

Phagocytosis

• [Amyloid-beta](/proteins/amyloid-beta) plaque phagocytosis
• Myelin debris clearance for remyelination
• Apoptotic neuron engulfment
• Synaptic pruning (complement-dependent and independent)

Role in Disease

Alzheimer's Disease — Disease-Associated Microglia

• Single-cell RNA-seq of 5xFAD mouse brains identified CLEC7A as a top Stage 2 DAM marker
• CLEC7A+ microglia form a physical barrier around amyloid plaques, compacting them and limiting neuritic dystrophy
• [TREM2](/genes/trem2) loss-of-function (e.g., R47H variant) prevents CLEC7A upregulation, locking microglia in a dysfunctional intermediate state
• Human AD brain single-nucleus RNA-seq confirms CLEC7A as a conserved DAM marker
• CLEC7A expression correlates with Braak stage and plaque density

Multiple Sclerosis

• Protective: Promotes myelin debris phagocytosis, enabling remyelination by [oligodendrocyte precursors](/cell-types/oligodendrocyte-precursor-cells)
• Pathogenic: Excessive Dectin-1 signaling can amplify inflammatory demyelination through IL-17 and GM-CSF production

ALS and Aging

Therapeutic Targeting

Beta-Glucan Agonists

• Systemic administration of particulate beta-glucan (curdlan, whole glucan particles) in AD mouse models enhances amyloid phagocytosis and improves cognition
• Trained immunity: Beta-glucan epigenetically reprograms myeloid cells for enhanced responsiveness, potentially providing long-lasting benefit

Indirect Modulation via TREM2

See Also

• CLEC7A Gene
• [TREM2 Protein](/proteins/trem2-protein)
• [Microglia](/cell-types/microglia)
• SYK Gene
• [Disease-Associated Microglia](/cell-types/alzheimers-microglia)

External Links

• [UniProt: Q9BXN2](https://www.uniprot.org/uniprot/Q9BXN2)
• [PDB: 2CL8](https://www.rcsb.org/structure/2CL8)
• [GeneCards: CLEC7A](https://www.genecards.org/cgi-bin/carddisp.pl?gene=CLEC7A)

References