Fig. 1.

Connexin (Cx)26-D50A and Cx26-A88V induce large hemichannel currents in Xenopus oocytes. Single cells were clamped at a holding potential of −40 mV and subjected to voltage pulses ranging from −30 to +60 mV in 10-mV steps. A: H₂O-injected cells displayed negligible membrane currents. Wild-type Cx26 (B)-, Cx26-D50A (C)-, and Cx26-A88V (D)-expressing oocytes exhibited hemichannel currents with both of the keratitis-ichthyosis-deafness (KID) syndrome mutation hemichannels displaying much larger currents than wild-type. E: steady-state currents from each pulse were plotted as a function of membrane voltage. Steady-state currents in H₂O-injected control cells (□) were negligible at all membrane voltages. Cx26 currents (●) were similar to those observed in control cells at lower voltages but increased at higher membrane voltage. Cx26-D50A (▲)- or Cx26-A88V (■)-expressing cells exhibited significantly increased steady-state currents compared with either control or Cx26 oocytes. Data are the means ± SE.