Anion Permeation in Ca2+-Activated Cl− Channels

  title={Anion Permeation in Ca2+-Activated Cl− Channels},
  author={Zhi Qiang Qu and H Criss Hartzell},
  journal={The Journal of General Physiology},
  pages={825 - 844}
Ca(2+)-activated Cl channels (Cl(Ca)Cs) are an important class of anion channels that are opened by increases in cytosolic [Ca(2+)]. Here, we examine the mechanisms of anion permeation through Cl(Ca)Cs from Xenopus oocytes in excised inside-out and outside-out patches. Cl(Ca)Cs exhibited moderate selectivity for Cl over Na: P(Na)/P(Cl) = 0.1. The apparent affinity of Cl(Ca)Cs for Cl was low: K(d) = 73 mM. The channel had an estimated pore diameter >0.6 nm. The relative permeabilities measured… CONTINUE READING