Fig. 6.
Multiple residues within the γ-subunit contribute to the channel's response to external Na+. A: amiloride-sensitive Iss/Ipeak ratios (left) and time constants of current decay (τ, right) of wild-type channels or channels with selected β-subunit residues substituted into the γ-subunit (at the indicated sites) were determined. Dashed lines represent the average values of αβγ-βTM2 channels from 45 observations (oocytes harvested from nine frogs). The average values of wild-type channels are from 31 observations (9 batches of oocytes), whereas mutant data are from 9 to 14 observations from 2 or 3 batches of oocytes. Values that were significantly different from that of the wild-type channel (*P < 0.05, determined by one-way ANOVA followed by a Bonferroni test) are shown as black (decreased value) or white (increased value) bars.