| Property | Value |
|----------|-------|
| **Protein Name** | Nicotinic acetylcholine receptor subunit alpha-2 |
| **Gene** | [CHRNA2](/genes/chrna2) |
| **UniProt ID** | [P43681](https://www.uniprot.org/uniprot/P43681) |
| **PDB ID** | 6PV6, 7KQ7 |
| **Molecular Weight** | ~56 kDa |
| **Subcellular Localization** | Plasma membrane (neuronal ligand-gated ion channel) |
| **Protein Family** | Cys-loop receptor family; Nicotinic acetylcholine receptor |
Nicotinic acetylcholine receptor subunit alpha-2 is a protein encoded by the CHRNA2 gene that chrna2-containing receptors are expressed in the central and peripheral nervous system:. This page describes its structure, normal nervous system function, role in neurodegenerative disease, and potential as a therapeutic target.
CHRNA2 encodes the alpha-2 subunit of neuronal nicotinic acetylcholine receptors (nAChRs). These receptors are pentameric ligand-gated ion channels typically composed of alpha and beta subunits:
- N-terminal extracellular domain: Contains the acetylcholine binding site at alpha-beta subunit interfaces
- Cys-loop motif: Conserved feature of the Cys-loop receptor superfamily
- Transmembrane domains (M1-M4): Form the channel pore
- Intracellular loop: Contains sites for phosphorylation and trafficking signals
CHRNA2 typically co-assembles with CHRNA4, CHRNA7, or CHRNB2/3/4 to form functional receptors.
CHRNA2-containing receptors are expressed in the central and peripheral nervous system:
- Presynaptic modulation: Regulates neurotransmitter release including glutamate, GABA, and dopamine
- Sensory processing: Involved in auditory and visual processing pathways
- Autonomic function: Modulates autonomic ganglia transmission
- Cognitive function: Contributes to attention, learning, and memory processes
The alpha-2 containing receptors have distinct pharmacological profiles compared to other neuronal nAChR subtypes.
CHRNA2 has several connections to neurodegenerative processes:
- Cholinergic system degeneration in AD affects nAChR signaling
- Alpha-2 receptors may have protective roles in amyloid-beta toxicity
- Genetic variants in CHRNA2 associated with AD risk in some populations
- Nicotine exposure (via alpha-2 receptors) may have neuroprotective effects
- Dopaminergic neuron survival influenced by nAChR signaling
- CHRNA2 variants associated with PD risk
- Nicotinic agonists being explored for neuroprotection in PD
- CHRNA2 mutations cause autosomal dominant nocturnal frontal lobe epilepsy
- Links to neuronal excitability disorders
- Varenicline: Partial agonist at alpha-4/beta-2 receptors; also affects alpha-2 containing receptors
- Cytisine: Traditional smoking cessation agent
- Target for novel neuroprotective drugs
- Gene therapy for epilepsy
- Biomarker for cholinergic system integrity