A pharmacological master key mechanism that unlocks the selectivity filter gate in K+ channels

Potassium (K+) channels have been evolutionarily tuned for activation by diverse biological stimuli, and pharmacological activation is thought to target these specific gating mechanisms. Here we report a class of negatively charged activators (NCAs) that bypass the specific mechanisms but act as master keys to open K+ channels gated at their selectivity filter (SF), including many two-pore domain K+ (K2P) channels, voltage-gated hERG (human ether-à-go-go–related gene) channels and calcium (Ca2+)–activated big-conductance potassium (BK)–type channels. Functional analysis, x-ray crystallography, and molecular dynamics simulations revealed that the NCAs bind to similar sites below the SF, increase pore and SF K+ occupancy, and open the filter gate. These results uncover an unrecognized polypharmacology among K+ channel activators and highlight a filter gating machinery that is conserved across different families of K+ channels with implications for rational drug design.

Source: ScienceNOW - February 21, 2019 Category: Science Authors: Schewe, M., Sun, H., Mert, U., Mackenzie, A., Pike, A. C. W., Schulz, F., Constantin, C., Vowinkel, K. S., Conrad, L. J., Kiper, A. K., Gonzalez, W., Musinszki, M., Tegtmeier, M., Pryde, D. C., Belabed, H., Nazare, M., de Groot, B. L., Decher, N., Fakler, Tags: Biochemistry reports Source Type: news