A synergistic blocking effect of Mg²⁺ and spermine on the inward rectifier K⁺ (Kir2.1) channel pore.

ABSTRACT: Inward rectifier K(+) channels (Kir2.1) exhibit an extraordinary rectifying feature in the current-voltage relationship. We have previously showed that the bundle-crossing region of the transmembrane domain constitutes the crucial segment responsible for the polyamine block. In this study, we demonstrated that the major blocking effect of intracellular Mg(2+) on Kir2.1 channels is also closely correlated with K(+) current flow, and the coupled movements of Mg(2+) and K(+) seem to happen in the same flux-coupling segment of the pore as polyamines. With a preponderant outward K(+) flow, intracellular Mg(2+) would also be pushed to and thus stay at the outermost site of a flux-coupling segment in the bundle-crossing region of Kir2.1 channels to block the pore, although with a much lower appar

SUBMITTER: Huang CW 

PROVIDER: S-EPMC4751470 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature