CLH-3b S74E, S747E mutant channels are constitutively inhibited and unaffected by GCK-3. (A) Current-to-voltage relationships of the S742E, S747E double mutant coexpressed with functional or KD GCK-3. Values are means ± SE (n = 6–7). (B) Activation voltages and 50% rise times of whole cell currents in cells coexpressing S742E, S747E and KD GCK-3 or GCK-3. Values are means ± SE (n = 6–7). *, P < 0.01 compared with KD GCK-3 isotonic. (C) Effect of cell swelling on current amplitude in cells coexpressing S742E, S747E and KD GCK-3 or GCK-3. Values are means ± SE (n = 6–7). Data were obtained as described in the legend to Fig. 1.