Figure 5. Biophysical characteristics of KCNQ5 current.

Properties of I _KCNQ5 are developed using experimental data from cloned mammalian KCNQ5 expressed in Xenopus laevis oocytes (black) and other expression systems (gray) [31], [32], [34], [36], [38]–[42]. A, V-dependent activation steady state (n _Q5∞). B, V-dependent steady states for fast inactivation (w _Q5∞) and slow inactivation (s _Q5∞). C, V-dependent activation time constants (τ_{n Q5f} and τ_{n Q5s}). τ_{n Q5f} is V -dependent but τ_{n Q5s} is set as a constant at 1 s. D, V-dependent time constants for fast inactivation (τ_{w Q5}) and slow inactivation (τ_{s Q5}). E and F, simulated time tracings of I _KCNQ5 with two different voltage-clamp protocols (insets) used in Jensen et al. (2007) [32] and the experimental time tracings are shown for comparison. (Experimental tracing adapted with permission from Jensen et al. (2007); copyright 2007, Biophysical Society.) G, simulated I–V relationship of I _KCNQ5 using the same voltage-clamp protocol as in E. All I–V data are normalized to the maximal current value at V = 40 mV.