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. 2016 Sep 9;2(9):e1501228. doi: 10.1126/sciadv.1501228

Fig. 7. Oxidation state–dependent electrophysiology measurements confirm that KCNQ1 Leu142 and KCNE3 Met59 residues are in close contact, as are KCNE3 Ser82 and KCNQ1 Gln244.

Fig. 7

(A) Average whole-cell currents recorded from cells transiently expressing KCNQ1 Leu142Cys plus KCNE3 Met59Cys exposed to control bath solution, +DTT, or Cu-phenanthroline (Cu-phen.). The solid line between the two traces indicates the zero current. (B) Voltage dependence of activation for currents recorded from cells expressing KCNQ1 Leu142Cys plus KCNE3 Met59Cys exposed to control bath solution (○), +DTT (▪), or Cu-phenanthroline (♦). (C) Average current-voltage (I-V) relationships normalized by membrane capacitance measured from cells expressing KCNQ1 Leu142Cys plus KCNE3 Met59Cys exposed to control bath solution (○), +DTT (▪), or Cu-phenanthroline (♦). (D) The KCNQ1 Cys122Ser/Gln244Cys + KCNE3 Ser82Cys complex is sensitive to DTT, suggesting that KCNQ1 Gln244Cys and KCNE3 Ser82Cys are in close enough contact with each other to spontaneously form a disulfide bond. (E) Average I-V normalized by membrane capacitance measured from cells expressing WT KCNQ1 plus KCNE3 Ser82Cys exposed to control bath solution (○), +DTT (▪), or Cu-phenanthroline (♦). (F) Average I-V normalized by membrane capacitance measured from cells expressing KCNQ1 Cys122Ser/Gln244Cys plus KCNE3 Ser82Cys exposed to control bath solution (○), +DTT (▪), or Cu-phenanthroline (♦). I tailmax, tail current maximum.