XB-IMG-120636
Xenbase Image ID: 120636
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Figure 14. Mutations shown to affect the pH sensitivity of Cx43 have little effect on Cx46. Hemichannel currents were induced by a series of 20-s depolarizing voltage steps separated by 70 s; the displayed interval between steps is truncated to 10 s for clarity. Voltage was held at â60 mV between depolarizing steps. In all cases, medium equilibrated with 100% CO2 was applied between the second and third depolarizations, and was washed out after the fourth depolarization. Wild-type Cx46 currents were nearly abolished with medium equilibrated with 100% CO2. Cx46ÎCT259, a mutant lacking 82% of the COOH terminus, and the mutant Cx46*H95D hemichannel behaved similarly to wild-type Cx46. Full recovery for these three hemichannel types occurred, on average, by the fourth episode after washout. The small variation in the time to full recovery seen among these three different hemichannel types was similar to that seen for oocytes expressing the same hemichannel type (n = 4, data not shown). In contrast, the mutant Cx46*H95C hemichannel, while similarly sensitive to CO2 application, recovered considerably more slowly upon washout, requiring twice as long as the three previous hemichannel types. Hemichannel currents were elicited by voltage steps to +5 mV for wild-type Cx46 and Cx46*H95D, +10 mV for Cx46ÎCT259, and +15 mV for Cx46*H95C. Image published in: Trexler EB et al. (1999) Image reproduced on Xenbase with permission of the publisher and the copyright holder. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |