A single charged voltage sensor is capable of gating the Shaker K+ channel.

ABSTRACT: We sought to determine the contribution of an individual voltage sensor to Shaker's function. Concatenated heterotetramers of Shaker zH4 Delta(6-46) wild type (wt) in combination with a neutral S4 segment Shaker mutant (mut) with stoichiometries 2wt/2mut and 1wt/3mut were studied and compared with the 4wt concatenated homotetramer. A single charged voltage sensor is sufficient to open Shaker conductance with reduced delay (<1 ms) and at more hyperpolarized voltages compared with 4wt. In addition, the wt-like slow inactivation of 1wt/3mut was almost completely eliminated by mutations T449V-I470C in its single wt subunit, indicating that the subunits bearing a neutral S4 were unable to trigger slow inactivation. Our results strongly suggest that a neutral S4 segment of Shaker's subunit is vo

SUBMITTER: Gagnon DG 

PROVIDER: S-EPMC2712970 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature