Nicotinic acetylcholine receptor
IPR002394
Definition
Nicotinic acetylcholine receptors are ligand-gated ion channels that mediate signal transduction at the post-synaptic membrane of cholinergic synapses, such as the neuromuscular junction PMID:1721053. They belong to a family of neurotransmitter-gated receptors, including glycine, gamma-aminobutyric-acid (GABA), serotonin 5HT3 receptors. These are oligomeric transmembrane (TM) complexes (pentamers of 2 alpha and 1 beta, 1 gamma and 1 delta subunit) that contain a central channel, which transiently opens upon binding of a specific neurotransmitters. Their sequences are related and share the same topology: each has an extracellular, glycosylated N-terminal ligand-binding domain; 3 hydrophobic TM regions, which form the channel; a hydrophilic cytoplasmic domain; followed by a fourth putative TM region PMID:2465296. The nicotinic receptor ligand binding domain is a specialised pocket of aromatic and hydrophobic residues formed at interfaces between protein subunits that changes conformation to convert agonist binding into gating of an intrinsic ion channel PMID:12436411. Neurotransmitter ligand-gated ion channels are transmembrane receptor-ion channel complexes that open transiently upon binding of specific ligands, allowing rapid transmission of signals at chemical synapses [[cite:PMID:1721053], [cite:PMID:1846404]]. Five of these ion channel receptor families have been shown to form a sequence-related superfamily: Nicotinic acetylcholine receptor (AchR), an excitatory cation channel in vertebrates and invertebrates; in vertebrate motor endplates it is composed of alpha, beta, gamma and delta/epsilon subunits; in neurons it is composed of alpha and non-alpha (or beta) subunits PMID:18446614. Glycine receptor, an inhibitory chloride ion channel composed of alpha and beta subunits PMID:15383648. Gamma-aminobutyric acid (GABA) receptor, an inhibitory chloride ion channel; at least four types of subunits (alpha, beta, gamma and delta) are known PMID:18760291. Serotonin 5HT3 receptor, of which there are seven major types (5HT3-5HT7) PMID:10026168. Glutamate receptor, an excitatory cation channel of which at least three types have been described (kainate, N-methyl-D-aspartate (NMDA) and quisqualate) PMID:15165736. These receptors possess a pentameric structure (made up of varying subunits), surrounding a central pore. All known sequences of subunits from neurotransmitter-gated ion-channels are structurally related. They are composed of a large extracellular glycosylated N-terminal ligand-binding domain, followed by three hydrophobic transmembrane regions which form the ionic channel, followed by an intracellular region of variable length. A fourth hydrophobic region is found at the C-terminal of the sequence [[cite:PMID:1721053], [cite:PMID:1846404]].
16 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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