Cys-Loop Ligand Gated Channels

A site dedicated to the structure-function relationships of nicotinic acetylcholine (nACh) receptors, g-aminobutyric type A (GABA_A) receptor, glycine receptor and the Zn²⁺-activated ion channel (ZAC)

Anion Channels

Click on individual subunits below to view specific amino acids.

anionic channels

The homepage contains two dendrograms indicating the relatedness of human subunits that form cys-loop receptors specific for cations and anions, respectively. Cation channels are nicotinic acetylcholine receptors (nAChR), 5-hydroxytryptamine receptor type 3 ( 5-HT₃ ) receptors and the zinc-activated ion channel (ZAC). The anionic channels are g-aminobutyric acid type A ( GABA_A (includes r subunits sometimes referred to as GABA_C ) and glycine receptors. The dendrograms contain links to the receptors and their individual subunits. These pages give brief information about the subunits and links to their gene and amino acid sequences in Genbank. There are also diagrams of the subunit topology. Click on one of the eight regions of the subunit (N-terminal domain, TM1, TM1-2 loop, TM2, TM2-3 loop, TM3, TM3-4 loop, TM4) and these will link you to an expanded diagram annotated with the human amino acids. These diagrams lack the signal sequence. However amino acid numbering starts either at the beginning of the signal sequence or at the beginning of the mature polypeptide depending on the convention used for the specific subunit. Each amino acid in the mature polypeptide links to a page that indicates the corresponding amino acid in orthologous mouse and rat polypeptides with their appropriate numbering scheme. If the amino acid has been mutated the table will provide the identities of introduced amino acids. Links indicate the physicochemical properties of the amino acids . Additional links provide information about the functional consequences of the mutation.

A key goal of this project is to provide a convenient approach to exploring the functional roles of all homologous residues accross all 45 Cys-loop receptor subunits. With this in mind we divided the receptor into four functional domains: 1) agonist site, 2) transduction, 3) pore, and 4) cytoplasmic portals. These domains are represented by structural icons in the navigation side-bar. Amino acids not located in these domains can be found by following the links for each individual subunit.

Lauren Sherman, Sarah Baker, Christina Lee, Erica Steinman, Khin Sone, and Elizabeth Rodriguez