Figure 2.

hCLC-Ka/Barttin mediated currents are modulated by GlialCAM. (A) Pulse protocol. (B–D) Typical currents from oocytes injected with CLC-Ka and GlialCAM (B), CLC-Ka and Barttin (C), or CLC-Ka, Barttin, and GlialCAM (D). Amount of cRNA for each construct was kept constant in the different co-injections. In (C) and (D) same scale bars as in (B). From the tail current after the –140 mV prepulse, the initial current (I_max), shown in (E) and the steady state current (I_ss), shown in (F) were determined. A double exponential fit to this tail current yielded time constants and coefficients of the two exponential components (see Methods). Fast and slow time constants were for CLC-Ka/Barttin 43 ± 11 ms and 6.8 ± 1 ms, for CLC-Ka/Barttin/GlialCAM 36 ± 1 ms and 8.7 ± 0.3 ms, respectively (n = 10), i.e., not significantly different. (G) Ratio of slow (as) and fast coefficient (af) of the double exponential: the weight of the slow component is significantly increased by GlialCAM. (^∗∗∗p < 0.001, Student’s t-test), values are mean ± SE. (H–I) Cellular distribution of CLC-K1 in HeLa cells. Barttin-CLC-K1 alone is located uniformly in the plasma membrane and intracellularly (H) whereas GlialCAM leads to CLC-K1/barttin localization in regions of cell-cell contacts (I, arrow). To see this figure in color, go online.