Differences between ion binding to eag and HERG voltage sensors contribute to differential regulation of activation and deactivation gating.

ABSTRACT: HERG (KCNH2) and ether-à-go-go (eag) (KCNH1) are members of the same subfamily of voltage-gated K+ channels. In eag, voltage-dependent activation is significantly slowed by extracellular divalent cations. To exert this effect, ions bind to a site located between transmembrane segments S2 and S3 in the voltage sensor domain where they interact with acidic residues that are conserved only among members of the eag subfamily. In HERG channels, extracellular divalent ions significantly accelerate deactivation. To investigate the ionbinding site in HERG, acidic residues in S2 and S3 were neutralized singly or in pairs to alanine, and the functional effects of extracellular Mg(2+) were characterized in Xenopus oocytes. To modulate deactivation kinetics in HERG, divalent cations interact with eag

SUBMITTER: Lin MC 

PROVIDER: S-EPMC2847495 | biostudies-literature | 2007 Nov-Dec

REPOSITORIES: biostudies-literature