Expression of anoctamins in murine tissues and FRT cells demonstrated that ANO1, 6, 7, 8, 9, and 10 are predominantly epithelial, with ANO1, 2, 6, 7, and 10 producing Ca2+-activated Cl- currents.
The calcium-activated chloride channel anoctamin1 (ANO1; TMEM16A) is fundamental for the function of epithelial organs. Mice lacking ANO1 expression exhibit transport defects and a pathology similar to cystic fibrosis. They also show a general defect of epithelial electrolyte transport. Here we analyzed expression of all ten members (ANO1-ANO10) in a broad range of murine tissues and detected predominant expression of ANO1, 6, 7, 8, 9, 10 in epithelial tissues, while ANO2, 3, 4, 5 are common in neuronal and muscle tissues. When expressed in Fisher Rat Thyroid (FTR) cells, all ANO proteins localized to the plasma membrane but only ANO1, 2, 6, and 7 produced Ca(2+)-activated Cl(-) conductance, as analyzed by ATP-induced iodide quenching of YFP fluorescence. In contrast ANO9 and ANO10 suppressed baseline Cl(-) conductance and coexpression of ANO9 with ANO1 inhibited ANO1 activity. Patch clamping of ANO-expressing FRT cells indicated that apart from ANO1 also ANO6 and 10 produced chloride currents, albeit with very different Ca(2+) sensitivity and activation time. We conclude that each tissue expresses a set of anoctamins that form cell- and tissue-specific Ca(2+)-dependent Cl(-) channels.
Schreiber et al. (Fri,) reported a other. Expression of anoctamins (ANO1-ANO10) was evaluated on Ca(2+)-activated Cl(-) conductance and chloride currents. Expression of anoctamins in murine tissues and FRT cells demonstrated that ANO1, 6, 7, 8, 9, and 10 are predominantly epithelial, with ANO1, 2, 6, 7, and 10 producing Ca2+-activated Cl- currents.