The isolated voltage sensing domain of the Shaker potassium channel forms a voltage-gated cation channel
- Université de Montréal, Canada
Figures
Figure 1
Expression of Shaker-iVSD lacking pore domains is sufficient to reconstitute voltage-dependent channel activity.
(a) Top: topology of Shaker K+ channel. Amino acid positions relevant to the present study are highlighted in yellow. Middle: Shaker channels constructs (Shaker-W434F and Shaker-iVSD) used in the …
Figure 2
Selectivity of Shaker-iVSD-induced current in high buffer (HB) solutions or NMDG+-based solutions.
(a)Top. Normalized IV relationships of Shaker-iVSD induced currents under different external pH conditions with HB solutions. Tail currents were evoked by 250 ms voltage pulses ranging from −180 to +…
Figure 3 with 1 supplement
Inhibition of Shaker-iVSD-induced ionic currents by external ZnCl2.
(a) Ionic currents and normalized fluorescence traces recorded from oocytes expressing Shaker-iVSD before and after the application of 2~20 µM ZnCl2 using cut-open technique (see inset for protocol).…
Figure 3—figure supplement 1
Effect of Zn2+ on fluorescence (left) and gating currents (right).
Fluorescence changes reduced significantly upon addition of Zn2+ and recover upon washout. Gating currents were inhibited upon addition of 5 µM Zn2+. At 5 µM Zn2+, tail currents at hyperpolarized …
Figure 4
Conformational changes in Shaker-iVSD.
Shaker-iVSD displays slow voltage-dependent fluorescence quenching in oocytes under voltage-clamp using cut-open oocyte technique. (a) Typical fluorescence signals are shown for Shaker-iVSD and …
Figure 5
Mode shift in Shaker-iVSD.
(a) FV relationships at 7 different holding potentials of Shaker-iVSD (left) and Shaker-W434F (right). Smooth curves were fits to a Boltzmann function yielding the following V1/2 and dV values: for …
