Fig. 7.

CMTX mutations in the middle cytoplasmic loop of Cx32 increase the sensitivity of intercellular channels to cytoplasmic acidification. Oocyte pairs were perfused with modified Barth’s (MB) solution equilibrated with 100% CO₂ for 10 min (horizontal bar), after which the perfusion medium was returned to normal MB to allow the junctional conductance to recover. Junctional conductance was normalized to the average conductance values recorded for 3 min before the start of perfusion with 100% CO₂. In A, the dashed linerepresents the average values of junctional conductance measured between pairs expressing Cx32wt during perfusion with normal MB (n = 3). In the case of E102G (C;n = 5) and Del111–116 (D;n = 4), both the rate and extent of pH-dependent uncoupling were enhanced greatly. The pH sensitivity of L56F (B; n = 5) and R220stop (E; n = 5) was similar to that of Cx32wt (A; n = 5). Results are shown as the mean ± SEM of the specified number of pairs.