![Highly permeable anions enhance the apparent Ca2+sensitivity in WT TMEM16A. (A) Macroscopic currents induced by application of increasing [Ca2+]i (indicated at the top of the recordings) to the cytosolic side of inside-out patches held at +80 mV. The extracellular side of the patches was exposed to a solution containing 140 mM of Cl− (black, n = 7), SCN− (blue, n = 6), F− (green, n = 6), or NO3− (red, n = 6). [Cl−]i = 40 mM, pHe = pHi = 7.3. (B) Concentration–response curves constructed with the current magnitudes shown in A. We used Hill equation fits (continuous lines) to compute EC50 and nH coefficient. (C) Relationship between the permeability ratios of foreign anions present on the extracellular side and the EC50 and nH coefficient. Permeability ratios were calculated as described in the legend of Fig. 5. **, Ca2+ EC50 values are statistically different (P = 0.01) from the Ca2+ EC50 calculated in the presence of Cl−. The data were analyzed using one-way ANOVA with a Tukey’s post-hoc test.](https://cdn.rupress.org/rup/content_public/journal/jgp/154/8/10.1085_jgp.202113027/2/jgp_202113027_fig2.png?Expires=1773586151&Signature=CWwA04Jom5VZ1PE8ghsamdHxC3yYy3y4pcvGi01vxEAKFkyl~XPoIl4xQfcJoD16oXBzDiIOpwszdDOeV~4H2bT6yapsDqH1nz-rBf9mbHaq7whMrMyaxQBxRTZ9-MvuX0Y~Rxn1-l61rIMiAfxwySc4P8Ov6DXY2O~GER9ogwX5gJ0wWJlFgjhtrXt3BVWzxLS73Gp6zeDX1XO~jvPq7aA6U567r~Ratug8by8VwuoWaW7OheIZch2QXSgOoNiEXlwl6x90fUIpPGRhDuW5fMAy97IeXyQSa8zeJ7wOPuxwrkCVjYW3B2k1iRAcQ7J9PMOphWMwvs7grqIQjHQMuw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Highly permeable anions enhance the apparent Ca 2+ sensitivity in WT TMEM16A. (A) Macroscopic currents induced by application of increasing [Ca2+]i (indicated at the top of the recordings) to the cytosolic side of inside-out patches held at +80 mV. The extracellular side of the patches was exposed to a solution containing 140 mM of Cl− (black, n = 7), SCN− (blue, n = 6), F− (green, n = 6), or NO3− (red, n = 6). [Cl−]i = 40 mM, pHe = pHi = 7.3. (B) Concentration–response curves constructed with the current magnitudes shown in A. We used Hill equation fits (continuous lines) to compute EC50 and nH coefficient. (C) Relationship between the permeability ratios of foreign anions present on the extracellular side and the EC50 and nH coefficient. Permeability ratios were calculated as described in the legend of Fig. 5. **, Ca2+ EC50 values are statistically different (P = 0.01) from the Ca2+ EC50 calculated in the presence of Cl−. The data were analyzed using one-way ANOVA with a Tukey’s post-hoc test.