BK channel inhibition by strong extracellular acidification.

ABSTRACT: Mammalian BK-type voltage- and Ca²⁺-dependent K⁺ channels are found in a wide range of cells and intracellular organelles. Among different loci, the composition of the extracellular microenvironment, including pH, may differ substantially. For example, it has been reported that BK channels are expressed in lysosomes with their extracellular side facing the strongly acidified lysosomal lumen (pH ~4.5). Here we show that BK activation is strongly and reversibly inhibited by extracellular H⁺, with its conductance-voltage relationship shifted by more than +100 mV at pH_O 4. Our results reveal that this inhibition is mainly caused by H⁺ inhibition of BK voltage-sensor (VSD) activation through three acidic residues on the extracellular side o

SUBMITTER: Zhou Y 

PROVIDER: S-EPMC6054526 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature