The S4-S5 linker of KCNQ1 channels forms a structural scaffold with the S6 segment controlling gate closure.

In vivo, KCNQ1 α-subunits associate with the β-subunit KCNE1 to generate the slowly activating cardiac potassium current (I(Ks)). Structurally, they share their topology with other Kv channels and consist out of six transmembrane helices (S1-S6) with the S1-S4 segments forming the voltage-sensing domain (VSD). The opening or closure of the intracellular channel gate, which localizes at the bottom of the S6 segment, is directly controlled by the movement of the VSD via an electromechanical coupling.

Kv2.1 and silent Kv subunits underlie the delayed rectifier K+ current in cultured small mouse DRG neurons.

Silent voltage-gated K(+) (K(v)) subunits interact with K(v)2 subunits and primarily modulate the voltage dependence of inactivation of these heterotetrameric channels. Both K(v)2 and silent K(v) subunits are expressed in the mammalian nervous system, but little is known about their expression and function in sensory neurons. This study reports the presence of K(v)2.

Kv channel gating requires a compatible S4-S5 linker and bottom part of S6, constrained by non-interacting residues.

Voltage-dependent K(+) channels transfer the voltage sensor movement into gate opening or closure through an electromechanical coupling. To test functionally whether an interaction between the S4-S5 linker (L45) and the cytoplasmic end of S6 (S6(T)) constitutes this coupling, the L45 in hKv1.5 was replaced by corresponding hKv2.

A Kv channel with an altered activation gate sequence displays both "fast" and "slow" activation kinetics.

The Kv1-4 families of K+ channels contain a tandem proline motif (PXP) in the S6 helix that is crucial for channel gating. In human Kv1.5, replacing the first proline by an alanine resulted in a nonfunctional channel.

Gambierol, a toxin produced by the dinoflagellate Gambierdiscus toxicus, is a potent blocker of voltage-gated potassium channels.

In this study, we pharmacologically characterized gambierol, a marine polycyclic ether toxin which is produced by the dinoflagellate Gambierdiscus toxicus. Besides several other polycyclic ether toxins like ciguatoxins, this scarcely studied toxin is one of the compounds that may be responsible for ciguatera fish poisoning (CFP). Unfortunately, the biological target(s) that underlies CFP is still partly unknown.

Role of the S6 C-terminus in KCNQ1 channel gating.

Co-assembly of KCNQ1 alpha-subunits with KCNE1 beta-subunits results in the channel complex underlying the cardiac IKs current in vivo. Like other voltage-gated K+ channels, KCNQ1 has a tetrameric configuration. The S6 segment of each subunit lines the ion channel pore with the lower part forming the activation gate.

Functional effects of a KCNQ1 mutation associated with the long QT syndrome.

Objective: Long QT syndrome (LQTS) is an inherited disorder of ventricular repolarization caused by mutations in cardiac ion channel genes, including KCNQ1. In this study the electrophysiological properties of a LQTS-associated mutation in KCNQ1 (Q357R) were characterized. This mutation is located near the C-terminus of S6, a region that is important for the gate structure.

Domain analysis of Kv6.3, an electrically silent channel.

The subunit Kv6.3 encodes a voltage-gated potassium channel belonging to the group of electrically silent Kv subunits, i.e.

Coupling of voltage sensing to channel opening reflects intrasubunit interactions in kv channels.

Voltage-gated K(+) channels play a central role in the modulation of excitability. In these channels, the voltage-dependent movement of the voltage sensor (primarily S4) is coupled to the (S6) gate that opens the permeation pathway. Because of the tetrameric structure, such coupling could occur within each subunit or between adjacent subunits.

Gating of shaker-type channels requires the flexibility of S6 caused by prolines.

The recent crystallization of a voltage-gated K+ channel has given insight into the structure of these channels but has not resolved the issues of the location and the operation of the gate. The conserved PXP motif in the S6 segment of Shaker channels has been proposed to contribute to the intracellular gating structure. To investigate the role of this motif in the destabilization of the alpha-helix, both prolines were replaced to promote an alpha-helix (alanine) or to allow a flexible configuration (glycine).