- Peptide CYEGVNILRIPAKR, corresponding to amino acid residues 95-108 of rat nAChRβ4 (Accession P12392). Extracellular, N-terminus.
- Rat dorsal root ganglion (1:100).
- Expression of nAChR β4 in rat DRGImmunohistochemical staining of rat dorsal root ganglion (DRG) frozen sections using Anti-Nicotinic Acetylcholine Receptor β4 (CHRNB4) (extracellular)-ATTO Fluor-594 Antibody (#ANC-014-AR), (1:100). A. nAChRβ4 labeling (red) appears in neuronal cell bodies. B. Nuclear staining using DAPI as counterstain (blue). C. Merged images of A and B.
- Human SH-SY5Y neuroblastoma cells (1:100).
Acetylcholine, released by cholinergic neurons, activates two groups of acetylcholine receptors (AChRs); muscarinic AChRs (mAChRs), which belong to the G-protein coupled receptor (GPCR) superfamily, and nicotinic AChRs (nAChRs), which belong to the ligand-gated ion channel superfamily. nAChRs also respond to nicotine, hence their name1.
To date, 17 different but related subunits of nAChRs have been identified and cloned. They consist of α subunits (α1-10), which are responsible for the binding of ligands. In fact, this subunit includes a Cys-loop in the first extracellular domain that is required for agonist binding2. The other subunits responsible for making up the active receptor are the β (β1-4), γ, δ and ε subunits3. Structurally, all subunits have the following: a conserved large extracellular N-terminal domain, three conserved transmembrane domains, a variable cytoplasmic loop and a fourth transmembrane domain with a short extracellular C-terminal domain. An active nAChR is generally a heteropentamer of these various subunits organized around a central pore1.
While most β subunits are neuronal, the β1 subunit forms functional receptors along with other subunits in the muscle3. In neurons the α2-α6 and β2-β4 subunits form heteropentameric receptors, usually with a (αx)2(βy)3 stoichiometry3.