Receptor superfamilies nicotinic acetylcholine receptors

The receptors for acetylcholine, GABA, glycine and serotonin have a homologous structure and form a superfamily. The best-investigated representative of this superfamUy is the nicotinic acetylcholine receptor, for which extensive biochemical and structural data are available. The nicotinic acetylcholine receptor can be treated as a representative of the other receptors of the superfamUy since it can be assumed that the structure-function principles of this receptor apply to the others. 

Stroud, R. M., M. P. McCarthy, and M. Shuster, Nicotinic acetylcholine receptor superfamily of ligand-gated ion channels. Biochemistry 29 11009, 1990. 

Heritable Mutations in the Glycine, GABAa, and Nicotinic Acetylcholine Receptors Provide New Insights into the Ligand-Gated Ion Channel Receptor Superfamily... 

The insect GABA receptor-chloride ionophore complex is found in the CNS and also at peripheral neuromuscular sites. GABA receptors belong to a superfamily of ligand-gated ion channels known as Cys-loop receptors that include nicotinic acetylcholine receptors and glutamate-gated chloride channels (Lester, 2004). Cys-loop receptors are so named because... 

HT3 receptors belong to the ligand-gated ion channel receptor superfamily, similar to the nicotinic acetylcholine or GABAa receptors and share elec-trophysiological and structural patterns. The receptors... 

This picture was made by mathematically filtering electron micrographs of ordered, two-dimensional arrays of the receptor. Each of the four pentameric structures shown represents an individual acetylcholine receptor with its central transmembrane pore. The dark areas indicate the five subunits (a2fiy8). (From R. M. Stroud, M. P. McCarthy, and M. Schuster, Nicotinic acetylcholine receptor superfamily of ligand-gated ion channels,... 

These characteristics are shared with subunits that form other ion channels/receptors and thus define a receptor superfamily, usually referred to as the nicotinic family. All members in this superfamily function as either cation- or anion-selective channels, thereby mediating fast excitatory or inhibitory synaptic transmission. In mammalian cells, the cation-selective members include nicotinic and 5HTg receptors, whereas the anion-selective members include GABA, GAB Ac, and glycine receptors. Anion-selective channels in this family are also found in invertebrates these channels are gated by glutamate, 5-HT, histidine, and acetylcholine (1). 

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