Figure 7.

Kv4.2 tandem-dimer constructs. (A–C) Membrane topology cartoons illustrating different types of the generated tandem dimers. (A) The wt dimer. (B) The construct has a double-point mutation in the first α-subunit and no mutation in the second (concatenated) α-subunit (intrasubunit configuration). (C) The construct has an S6 point mutation in the first α-subunit and an S4S5 point mutation in the second α-subunit (intersubunit configuration). Individual point mutations in S4S5 and S6 are depicted by green and blue dots, respectively. (D–H) A-type currents mediated by the different dimer constructs were generated to test for intra- and intersubunit interactions of the coupling pairs G309/I412, S322/V404, E323/V404, and F326/V404 (inset: voltage protocol; only test pulses between −60 and +60 mV in 20 mV increments are shown). (D) Currents mediated by constructs generated to test for intersubunit interactions of the G309/I412 coupling pair. (E) The constructs generated to test for intrasubunit interactions of the S322/V404 coupling pair were coexpressed with KChIP2 and DPP6 (see Materials and Methods). (F) Currents mediated by constructs generated to test for intersubunit interactions of the S322/V404 coupling pair. (G) Currents mediated by constructs generated to test for intra- and intersubunit interactions of the E323/V404 coupling pair. (H) Currents mediated by constructs generated to test for intra- and intersubunit interactions of the F326/V404 coupling pair.