|PROSITE documentation PDOC00209 [for PROSITE entry PS00236]|
Neurotransmitter-gated ion-channels [1,2,3,4] provide the molecular basis for rapid signal transmission at chemical synapses. They are post-synaptic oligomeric transmembrane complexes that transiently form a ionic channel upon the binding of a specific neurotransmitter. Presently, the sequence of subunits from five types of neurotransmitter-gated receptors are known:
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.
The sequence of subunits from the AchR, GABA, 5HT3, and Gly receptors are clearly evolutionary related and share many regions of sequence similarities. These sequence similarities are either absent or very weak in the Glu receptors.
In the N-terminal extracellular domain of AchR/GABA/5HT3/Gly receptors, there are two conserved cysteine residues, which, in AchR, have been shown to form a disulfide bond essential to the tertiary structure of the receptor. A number of amino acids between the two disulfide-bonded cysteines are also conserved. We have therefore used this region as a signature pattern for this subclass of proteins.Note:
In most AchR subunits and in GABA β subunits, the residue N-terminal to the second cysteine is a N-glycosylated asparagine.Last update:
May 2004 / Text revised.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Stroud R.M., McCarthy M.P., Shuster M.|
|Title||Nicotinic acetylcholine receptor superfamily of ligand-gated ion channels.|
|Title||Ligand-gated ion channels in the brain: the amino acid receptor superfamily.|
|3||Authors||Dingledine R., Myers S.J., Nicholas R.A.|
|Source||FASEB J. 4:2632-2645(1990).|
|Title||Receptor classes and the transmitter-gated ion channels.|
|Source||Trends Biochem. Sci. 17:368-374(1992).|