Protons inhibit anoctamin 1 by competing with calcium

- ANO1 is a Ca2+-activated Cl− channel mediates numerous functions.
- Intracellular acid inhibits the Ca2+-activated ANO1 currents.
- Mutations at the Ca2+-binding site block the acid-induced inhibition.
- These results suggest that protons interfere with Ca2+.
- The acid-induced inhibition of ANO1 appears to be a feedback mechanism.