Development and validation of a potent and specific inhibitor for the CLC-2 chloride channel
Anna K. Koster, Austin L. Reese, Yuri A. Kuryshev, Xianlan Wen, Keri A. McKiernan, Erin E. Gray, Caiyun Wu, John R. Huguenard, Merritt Maduke, J. Du Bois
Abstract
= 17 ± 1 nM). AK-42 displays unprecedented selectivity (>1,000-fold) over CLC-1, the closest CLC-2 homolog, and exhibits no off-target engagement against a panel of 61 common channels, receptors, and transporters expressed in brain tissue. Computational docking, validated by mutagenesis and kinetic studies, indicates that AK-42 binds to an extracellular vestibule above the channel pore. In electrophysiological recordings of mouse CA1 hippocampal pyramidal neurons, AK-42 acutely and reversibly inhibits CLC-2 currents; no effect on current is observed on brain slices taken from CLC-2 knockout mice. These results establish AK-42 as a powerful tool for investigating CLC-2 neurophysiology.