UAS regulatory sequences drive expression of a fusion protein composed of a membrane-tethered form of the Uuuu\Charybdotoxin ion channel toxin (this toxin targets voltage-gated K[+] ion channels). The design of the fusion protein (PMID:15294139) is based on the structure of the lynx1-like gene family, and consists of a Tag:SS(lynx1) secretory signal sequence, the Uuuu\Charybdotoxin toxin peptide, a Gly-Asn repeat hydrophilic linker and a Tag:GPI(lynx1) anchor (this anchor sequence should result in the protein being tethered to the plasma membrane). In addition, the protein is tagged with Tag:MYC. The fusion protein is designed to act as a "tethered-toxin" to allow cell-autonomous modulation of ion channel (and hence neuronal cell) activity, but flies are viable when the protein is expressed pan-neuronally, suggesting that the Uuuu\Charybdotoxin toxin may be non-functional against fly voltage-gated K[+] channels (at least in its tethered form).