Figure 1. Differential functional effects of nanoRIIα targeted to either KCNE1 or KCNQ1 on I_Ks.

(A) Cartoon showing targeting GFP/YFP nanobody (nano) to Q1/E1 channel complex via a YFP tag on E1. (B) Exemplar I_Ks traces elicited by test pulses (+60 mV, –40 mV return) reconstituted in Chinese hamster ovary (CHO) cells expressing Q1/E1-YFP+nano at 1 min (black traces) or 3 min (red traces) after break-in to whole-cell configuration. Cells were dialyzed with internal solution either lacking (left) or including (right) 0.2 mM cAMP+0.2 μM okadaic acid (cAMP/OA). (C) Diary plot of population tail-current amplitudes (mean ± SEM) vs time with cAMP/OA either lacking (black symbols, n=10) or included (red symbols, n=11) in the patch pipette solution. (D–F) Cartoon, exemplar currents and population tail-current amplitude vs time for CHO cells expressing Q1/E1-YFP+nanoRIIα. Same format as (A–C). **p<0.01, two-tailed unpaired t-test. (G) Cartoon showing nanoRIIα targeting to Q1/E1 channel complex via YFP tag on Q1. (H) Exemplar I_Ks traces reconstituted in CHO cells expressing Q1-YFP/E1 with either nano (left) or nanoRIIα (right). (I) Population current densities (nano, n=26; nanoRIIα, n=17). ***p<0.001, two-tailed unpaired t-test.

Figure 1—figure supplement 1. NanoRIIα does not reconstitute protein kinase A (PKA) regulation of I_Ks when co-expressed with untagged KCNQ1+KCNE1.

(A) Schematic showing nanoRIIα co-expressed with Q1/E1 channel complex. (B) Diary plot of population tail-current amplitudes (mean ± SEM) vs time with cAMP/OA either lacking (black symbols, n=5) or included (red symbols, n=5–9) in the patch pipette solution.