AChRα1β1δε/γ | Muscle-type nicotinic acetylcholine receptor
The family has been devided into nicotinic acetylcholine receptors (ionotropic channels) and muscarinic acetylcholine receptors (metabotropic G-protein coupled receptors). Both subgroups are sensitive to acetylcholine.
Nicotinic acetylcholine receptors: As typical cys-loop receptors, acetylcholine receptor subunits contain four transmembrane spanning domains TM1-TM4. Five subunits form a pore, homomeric and heteromeric combinations are possible.17 vertebrate subunits have been identified: α genes: CHRNA1 - CHRNA10; β genes: CHRNB1 . CHRNB4, as well as CHRND (delta), CHRNE (epsilon), CHRNG (gamma)
Muscarinic acetylcholine receptors: 5 receptors have been described (M1 - M5), encoded by the 5 genes CHRM1 - CHRM5. These proteins contain seven transmembrane regions and do not form homo or heteromers.
AChRα1β1δε/γ: Background Information
The muscle-type nicotinic receptor is a multi-pass membrane protein complex and neurotransmitter-gated ion-channel, consisting of the subunit combination (α1)2β1δε (adult receptor) or (α1)2β1δγ (fetal receptor). It is located in the neuromuscular junction, where activation yields EPSP, mainly by increased Na+ and K+ conductance.
CHRNA1, CHRNB1, CHRND, CHRNE or CHRNG
UniProt P02708 (CHRNA1), P11230 (CHRNB1), Q07001 (CHRND), Q04844 (CHRNE), P07510 (CHRNG)
Isoform 1 of the alpha subunit CHRNA1 is only expressed in skeletal muscle. Isoform 2 is constitutively expressed in skeletal muscle, brain, heart, kidney, liver, lung and thymus
Signal transduction at the neuromuscular junction for skeletal muscle contraction
The alpha subunit CHRNA1 is the main focus for antibody binding in Myasthenia Gravis, Myasthenic Syndrome Congenital, 1B, Fast-Channel and Myasthenic Syndrome, Congenital, 1A, Slow-Channel
Alpha-conotoxin ImII, is clustered at the neuromuscular junction via the extracellular matrix protein agrin
Acetylcholine, carbachol, suxamethonium, α-Bungarotoxin, α-Conotoxin, Hexamethonium, Pancuronium, Tubocurarine
SSM-based technology (SURFE²R)
Reviews and Links
- Mammalian Nicotinic Acetylcholine Receptors: From Structure to Function; Physiol Rev 89: 73–120, 2009; doi:10.1152/physrev.00015.2008, Albuquergue et al;
Transporter classification database:
- Acetylcholine receptor subunit alpha (CHRNA1, Homo sapiens)
- Acetylcholine receptor subunit beta (CHRNB1, Homo sapiens)
- Acetylcholine receptor subunit delta (CHRND, Homo sapiens)
- Acetylcholine receptor subunit epsilon (CHRNE, Homo sapiens)
- Acetylcholine receptor subunit gamma (CHRNG, Homo sapiens)