20.500.12556/DKUM-98729 Allosteric coupling between transmembrane segment 4 and the selectivity filter of TALK1 potassium channels regulates their gating by extracellular pH Opening of two-pore domain K+ channels (K2Ps) is regulated by various external cues, such as pH, membrane tension, or temperature, which allosterically modulate the selectivity filter (SF) gate. However, how these cues cause conformational changes in the SF of some K2P channels remains unclear. Herein, we investigate the mechanisms by which extracellular pH affects gating in an alkaline-activated K2P channel, TALK1, using electrophysiology and molecular dynamics (MD) simulations. We show that R233, located at the N-terminal end of transmembrane segment 4, is the primary pHo sensor. This residue distally regulates the orientation of the carbonyl group at the S1 potassium-binding site through an interacting network composed of residues on transmembrane segment 4, the pore helix domain 1, and the SF. Moreover, in the presence of divalent cations, we found the acidic pH-activated R233E mutant recapitulates the network interactions of protonated R233. Intriguingly, our data further suggested stochastic coupling between R233 and the SF gate, which can be described by an allosteric gating model. We propose that this allosteric model could predict the hybrid pH sensitivity in heterodimeric channels with alkaline-activated and acidic-activated K2P subunits. potassium channel molecular dynamics molecular modeling structural model K2P TALK1 pH sensing C-type gate channel activation kalijev kanal molekulska dinamika molekulsko modeliranje strukturni model K2P TALK1 zaznavanje pH vrata tipa C aktivacija kanala true false true ASBMB Angleški jezik Slovenski jezik Znanstveno delo 2026-07-03 08:18:07 2026-07-03 08:26:09 2026-07-04 03:09:56 0000-00-00 00:00:00 2022 0 0 str. 1-13 št. 6, št. članka 101998 Letn. 298 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2022-04-19 2021-12-24 2022-04-29 612 283339523 10.1016/j.jbc.2022.101998 External Link 1083-351X RAZ_Tsai_Wen-Hao_2022.pdf RAZ_Tsai_Wen-Hao_2022.pdf 1 8A747359C9C34EC7B790D5C597BCAEC5 2be7d868781016215134a8791ba05ee577f12ed62361704ecd5d16463a74d62e c6c38ddc-76a7-11f1-9131-00155d580e34 https://dk.um.si/Dokument.php?lang=slv&id=207859 https://doi.org/10.1016/j.jbc.2022.101998 0 e6da66ac-76a7-11f1-9131-00155d580e34 https://dk.um.si/Dokument.php?lang=slv&id=207860 https://www.jbc.org/article/S0021-9258(22)00438-0/fulltext 1 f5d905d9-76a6-11f1-9131-00155d580e34 https://dk.um.si/Dokument.php?lang=slv&id=207857 Medicinska fakulteta 0 0 0