Exogenous CaM has no effect on Ano1 current in inside-out excised patches. (A and B) Excised patches were pulled from cells expressing Ano1(ac) (A) and Ano1(abc) (B) and exposed to 20 µM Ca²⁺ with or without 10 µM CaM as indicated at 100-mV holding potential. Application of CaM has no effect (n = 5–10). The inset in A compares rundown in excised patches not exposed to CaM (black) and patches exposed to 10 µM CaM (red) for 8 min. (C) Rundown was quantified before and during exposure to CaM as I_end/I_initial, where I_end is the current amplitude at the end and I_initial is the current amplitude at the start of a 1-min period. (D) Rundown of Ano1(abc) in response to 74.35 µM Ca²⁺ was not rescued by 10 µM CaM. (E and F) Ano1 rundown in the presence of 10 µM Ca is not affected by addition of 25 µM apo-CaM in the absence of Ca²⁺ or Ca²⁺-CaM. Rundown was quantified as in C. Error bars are ±SEM.