The zinc-activated channel (ZAC) is a member of the 'Cys-loop' family of pentameric ligand-gated ion channels that includes the nicotinic acetylcholine, 5-HT3, GABAA and glycine receptors [1-2]. Little is known of the native channel, but it is thought likely to be a homomeric complex of four transmembrane domain subunits that assemble to form a cation selective channel.

In mammalian expression systems, ZAC demonstrates constitutive activity that can be reversibly suppressed by (+)-tubocurarine. In whole-cell recordings, the amplitude of the spontaneous current mediated by ZAC increases with time [1]. Zinc is the only know positive modulator of the channel which is unresponsive to a range of agonists acting at other ligand-gated ion channel channels and G-protein coupled receptors [1]. ZAC is found in the human, chimpanzee, dog, cow and opossum genomes, but is absent from those of mouse, or rat [1-2].

1. Davies PA, Wang W, Hales TG, Kirkness EF. (2003) A novel class of ligand-gated ion channel is activated by Zn2+. J Biol Chem, 278 (2): 712-7. [PMID:12381728]

2. Houtani T, Munemoto Y, Kase M, Sakuma S, Tsutsumi T, Sugimoto T. (2005) Cloning and expression of ligand-gated ion-channel receptor L2 in central nervous system. Biochem Biophys Res Commun, 335 (2): 277-85. [PMID:16083862]