Ano1 (or TMEM16A, DOG1 and others) the first member to be identified was found to be a Ca2+-activated Cl- channel therefore other members are likely to also be Cl- channels. These channels are expressed in many different tissues: bronchiolar epithelial cells, pancreatic acinar cells, proximal kidney tubule epithelium, retina, dorsal root ganglia and submandibular gland1. In fact, Ano1 gained a lot of attention as its activation may serve as a therapeutic treatment for cystic fibrosis since it is also expressed in the airways6. These Ca2+-activated Cl- channels are believed to play a role in development as knock out of Ano1 in mice causes abnormal development of the trachea7. Ano2 (TMEM16B) has been shown to mediate Ca2+-activated Cl- current in olfactory epithelium and photoreceptor synapsesnAlthough relatively newly discovered channels, they are being discovered in many medical indications. Ano1 has become a marker in gastrointestinal tumors as its expression is significantly upregulated in such tumors. Similarly, Ano1 is also highly expressed other carcinomas.
