Nicotinic Acetylcholine Receptor
From Proteopedia
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=== Ion Channel === | === Ion Channel === | ||
| - | The ion channel of the protein is a 20 membered alpha helix bundle. This channel also contributes to the receptor function in three critical aspects: it contains a gating mechanism, it contains a water pore to | + | The ion channel of the protein is a 20 membered alpha helix bundle. This channel also contributes to the receptor function in three critical aspects: it contains a gating mechanism, it contains a water pore to stabilize ions, and it has a selectivity filter for ion charge. As with most transmembrane alpha helix bundles, it is hydrophobic around the edges to effectively be supported within the membrane, and it is hydrophilic on the inner portion to transport charged ions. |
== Physiology == | == Physiology == | ||
| - | The receptor is a | + | The receptor is a cylindrically-shaped protein. It is embedded in the cell wall of post synaptic nerves at the skeletal neuromuscular junction. The receptor acts as a chemically controlled sodium (Na) channel also known as a [[ligand gated channel]]. |
When in the presence of [[acetylcholine]], the receptor undergoes a conformational change opening up the channel to an influx of sodium (Na) within the cell. When this happens the cell undergoes a depolarization event that triggers an action potential to propagate along the rest of the cell stimulating, for example, a muscle response. | When in the presence of [[acetylcholine]], the receptor undergoes a conformational change opening up the channel to an influx of sodium (Na) within the cell. When this happens the cell undergoes a depolarization event that triggers an action potential to propagate along the rest of the cell stimulating, for example, a muscle response. | ||
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=== Clinical Findings === | === Clinical Findings === | ||
| - | Findings due to nicotinic stimulation from [[ | + | Findings due to nicotinic stimulation from [[Acetylcholinesterase inhibitors]] |
* Neuromuscular junctions of skeletal muscles | * Neuromuscular junctions of skeletal muscles | ||
| - | ** | + | ** Fasciculations and myotonic jerks |
** Weakness and paralysis of the muscle | ** Weakness and paralysis of the muscle | ||
Revision as of 17:33, 4 January 2016
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3D Structures of nicotinic acetylcholine receptor
Updated on 04-January-2016
4d01 – hAChR α-9 subunit extracellular domain – human
4uxu – hAChR α-9 subunit extracellular domain + methyllycaconitine
4uy2 – hAChR α-9 subunit extracellular domain + α-bungarotoxin
2qc1 – AChR α subunit extracellular domain + α-bungarotoxin - mouse
3mra – TcAChR α subunit M3 transmembrane segment – Torpedo californica - NMR
2k58 – AChR beta-2 subunit M1 transmembrane segment - NMR
2k59 – AChR beta-2 subunit M2 transmembrane segment - NMR
1oed – TmAChR pore – Torpedo marmorata – electron images
2bg9, 4aq5, 4aq9, 4bog, 4boi, 4bon, 4boo, 4bor, 4bot – TmAChR – Cryo-EM
References
1. Cholinesterase Inhibitors: Including Insecticides and Chemical Warfare Nerve Agents, Agency for Toxiz Substances and Disease Regulation accessed 5/2/14
2. Pierre-Jean Corringer and Jean-Pierre Changeux (2008) Nicotinic acetylcholine receptors. Scholarpedia, 3(1):3468.
3. Adcock C, Smith GR, Sansom MS. The nicotinic acetylcholine receptor: from molecular model to single-channel conductance. Eur Biophys J. 2000;29:29–37.
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Michal Harel, Joel L. Sussman, Alexander Berchansky, Alex Pennington
