| Property | Value |
|----------|-------|
| **Protein Name** | Nicotinic acetylcholine receptor subunit alpha-3 |
| **Gene** | [CHRNA3](/genes/chrna3) |
| **UniProt ID** | [P30532](https://www.uniprot.org/uniprot/P30532) |
| **PDB ID** | 5KLE, 6PV6 |
| **Molecular Weight** | ~57 kDa |
| **Subcellular Localization** | Plasma membrane (neuronal/autonomic ligand-gated ion channel) |
| **Protein Family** | Cys-loop receptor family; Nicotinic acetylcholine receptor |
Nicotinic acetylcholine receptor subunit alpha-3 is a protein encoded by the CHRNA3 gene that chrna3-containing receptors are widely expressed in the nervous system:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
CHRNA3 encodes the alpha-3 subunit of neuronal nicotinic acetylcholine receptors (nAChRs). Like other nAChR subunits:
- Extracellular N-terminal domain: Contains the ligand-binding site
- Cys-loop motif: Conserved sequence critical for receptor function
- Four transmembrane helices (M1-M4): Form the ion conduction pathway
- Intracellular loop: Contains trafficking signals and regulatory sites
CHRNA3 commonly assembles with CHRNA5, CHRNB2, CHRNB4, and CHRNA6 subunits to form functional receptor complexes in autonomic ganglia and certain brain regions.
CHRNA3-containing receptors are widely expressed in the nervous system:
- Autonomic ganglionic transmission: Mediates fast synaptic transmission in autonomic ganglia
- Presynaptic modulation: Regulates release of various neurotransmitters
- Sensory processing: Involved in pain signaling and visceral sensory transduction
- Adrenal medulla: Mediates acetylcholine-induced catecholamine release
- Cognitive function: Contributes to attention and memory processes
CHRNA3 plays significant roles in neurodegenerative processes:
- Cholinergic neuron loss in AD reduces nAChR signaling
- CHRNA3 expression changes in AD brain
- Genetic variants in CHRNA3-CHRNA5-CHRNB4 cluster associated with AD risk
- Nicotine use associated with reduced AD risk may involve alpha-3 receptors
- CHRNA3 polymorphisms linked to PD susceptibility
- Dopaminergic neuron protection by nicotinic signaling
- Smoking-associated neuroprotection hypothesis
- CHRNA3 variants associated with COPD and lung cancer
- May influence neurodegeneration through shared pathways
- Nicotinic signaling affects neuroinflammation
- ABT-594: Potent agonist, studied for cognitive enhancement
- TC-2559: Selective agonist for cognitive disorders
- Mecamylamine: Non-selective antagonist, used in research
- Bupropion: Affects nAChR function
- Smoking cessation (off-target effects)
- Cognitive enhancement
- Neuroprotection strategies