Figure 7

Effects of hKCNE3L and hKCNE4L on hKv4.2/3 steady-state inactivation and inactivation recovery with/without KChIP2.

(A) Upper, exemplar current trace recorded from Xenopus oocyte expressing hKv4.2+ KChIP2, using steady-state inactivation protocol (left inset). Tail current time-point used for quantifying available channels indicated by arrow. Dashed line indicates zero current level. Lower, mean ± SEM values for voltage dependence of steady-state inactivation (plotted as fraction of channels available at arrow in panel A versus voltage) quantified using Voltage protocol as in panel A, for currents generated in Xenopus oocytes expressing hKv4.2 alone (n = 6) or with hKCNE3L (E3L; n = 4) or hKCNE4L (E4L; n = 6); or Kv4.2+ KChIP2 alone (n = 6), or with hKCNE3L (E3L; n = 5) or hKCNE4L (E4L; n = 6). (B) Upper, exemplar current trace recorded from Xenopus oocyte expressing hKv4.3+ KChIP2, using steady-state inactivation protocol as in panel A. Tail current time-point used for quantifying available channels indicated by arrow. Dashed line indicates zero current level. Lower, mean ± SEM values for voltage dependence of steady-state inactivation (fraction of channels available at arrow in panel A versus voltage) quantified using Voltage protocol as in panel A, for currents generated in Xenopus oocytes expressing hKv4.3 alone (n = 6) or with hKCNE3L (E3L; n = 5); or hKv4.3 + KChIP2 alone (n = 9), or with hKCNE3L (E3L; n = 7). (C) Upper, exemplar current traces recorded using “short” and “long” inactivation recovery protocols (inset) from a Xenopus oocyte expressing hKv4.2 + KChIP2. Dashed line indicates zero current level. (D) Mean ± SEM values for the time course of recovery from inactivation for currents generated as in panel C in Xenopus oocytes expressing hKv4.2 alone (n = 6) or with hKCNE3L (E3L; n = 5) or hKCNE4L (E4L; n = 6); or Kv4.2 + KChIP2 alone (n = 6), or with hKCNE3L (E3L; n = 6) or hKCNE4L (E4L; n = 6). Left, close-up of first 1s of recovery; right, full 5s recovery period.