C3AR1 Gene

C3AR1 Gene

Overview

Pathway Diagram

C3AR1 Gene

Overview

Pathway Diagram

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">C3AR1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>C3AR1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Complement C3a Receptor 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>5p13.3</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>[719](https://www.ncbi.nlm.nih.gov/gene/719)</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>[ENSG00000171860](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000171860)</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>[Q16581](https://www.uniprot.org/uniprot/Q16581)</td>
</tr>
<tr>
<td class="label">Protein Name</td>
<td>C3a anaphylatoxin chemotactic receptor</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><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/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/cardiovascular" style="color:#ef9a9a">Cardiovascular</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">73 edges</a></td>
</tr>
</table>

C3AR1 (Complement C3a Receptor 1) encodes the C3a anaphylatoxin chemotactic receptor, a G protein-coupled receptor (GPCR) that mediates the biological effects of complement component C3a. In the central nervous system, C3AR1 is expressed on [microglia](/cell-types/microglia-neuroinflammation), [astrocytes](/entities/astrocytes), and [neurons](/entities/neurons), where it plays critical roles in neuroinflammation, synaptic pruning, and response to neurodegenerative pathology["@kemper2018"].

The [complement system](/entities/complement-system), particularly the C3a-C3aR axis, has emerged as a key mediator of neuroinflammation in Alzheimer's disease, [Parkinson's disease](/diseases/parkinsons-disease), and other neurodegenerative conditions. C3aR signaling can promote both protective and deleterious effects depending on disease stage and cellular context["@morgan2015"].

Gene Information

Function

C3AR1 encodes a seven-transmembrane G protein-coupled receptor that specifically binds the complement activation fragment C3a. Upon C3a binding, the receptor couples primarily to Gαi and Gαq proteins, leading to[@coulthard2015]:

In the CNS, C3aR signaling influences[@rahpeymai2021]:

• Microglial activation states and cytokine production
• Astrocyte reactivity and scar formation
• [Blood-brain barrier](/entities/blood-brain-barrier) permeability
• Synaptic plasticity and pruning

Expression

C3AR1 is expressed across multiple cell types:

Peripheral Expression

• Neutrophils: Primary site of expression; mediates chemotaxis
• Monocytes/macrophages: Regulates inflammatory responses
• Mast cells: Mediates degranulation and cytokine release
• Eosinophils: Promotes chemotaxis and activation

CNS Expression[@luo2020]

• Microglia: Constitutively expressed; upregulated during neuroinflammation
• Astrocytes: Induced under inflammatory conditions
• Neurons: Low basal expression; upregulated in disease states
• Endothelial cells: Contributes to BBB permeability changes

Disease Associations

Alzheimer's Disease

The C3a-C3aR axis contributes to Alzheimer's pathology through multiple mechanisms[@lian2016]:

GWAS studies have identified associations between C3AR1 polymorphisms and AD risk, particularly in variants affecting receptor expression levels[@crehan2012].

Parkinson's Disease

In Parkinson's disease, C3aR signaling contributes to[@wang2020]:

• Microglial activation in the substantia nigra
• Dopaminergic neuron vulnerability
• [α-synuclein](/proteins/alpha-synuclein)-induced neuroinflammation
• Progressive neurodegeneration

Multiple Sclerosis

C3aR plays a dual role in MS[@van2019]:

• Pro-inflammatory: Promotes Th17 responses and CNS inflammation
• Repair-promoting: May support remyelination in certain contexts

Stroke and Brain Injury

Following ischemic stroke, C3aR activation[@ahmad2019]:

• Increases BBB permeability
• Promotes edema formation
• Attracts peripheral immune cells
• Influences long-term tissue remodeling

Key Publications

Therapeutic Targeting

C3aR Antagonists

Several C3aR antagonists have been developed for inflammatory conditions[@woodruff2015]:

Clinical Relevance

C3aR targeting is being explored for[@mastorakos2021]:

• Neuroinflammatory diseases
• Age-related cognitive decline
• Traumatic brain injury
• Multiple sclerosis

Interactions

C3aR interacts with:

• C3a: Primary ligand (anaphylatoxin)
• Gαi/Gαq proteins: Signal transduction
• β-arrestin: Receptor desensitization
• Other complement receptors: [C5aR1](/genes/c5ar1), C5aR2 (functional crosstalk)

Related Pages

• [Complement System](/mechanisms/complement-system-neurodegeneration)
• [Microglia](/cell-types/microglia)
• [Neuroinflammation](/mechanisms/neuroinflammation)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [C5AR1](/genes/c5ar1)

See Also

• [C3AR1 Protein](/proteins/amyloid-beta)
• [Complement System](/mechanisms/complement-system-neurodegeneration)
• [Neuroinflammation](/mechanisms/neuroinflammation)
• [Alzheimer's Disease](/diseases/alzheimers-disease)

External Links

• [NCBI Gene: C3AR1](https://www.ncbi.nlm.nih.gov/gene/719)
• [Ensembl: ENSG00000171860](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000171860)
• [UniProt: Q16581](https://www.uniprot.org/uniprot/Q16581)
• [GeneCards: C3AR1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=C3AR1)
• [OMIM: C3AR1](https://omim.org/search?search=C3AR1)
• [Allen Brain Atlas: C3AR1](https://human.brain-map.org/microarray/search/show?search_term=C3AR1)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving C3AR1 Gene discovered through SciDEX knowledge graph analysis: