Figure 5. Slow temporal regulation of channel trafficking by targeted induced recruitment of nanoCα to Q1 C-terminus.
(A) Cartoon of FK506 binding protein (FKBP)/FKBP-rapamycin binding domain (FRB) heterodimerization strategy utilized for rapamycin-induced recruitment of engineered Cα to BBS-Q1-YFP/E1. (B) Exemplar flow cytometry contour plots showing surface expression (BTX-647 fluorescence) and CFP fluorescence in cells expressing BBS-Q1-YFP/E1 with FRB-Cα and FKBP-nano at times t=0 (left), t=6 hr (middle), and t=24 hr (right) after rapamycin addition. (C) Normalized mean Q1 surface density (BTX-647 fluorescence) plotted as a function of time after rapamycin induction. (D) Normalized mean Q1 total expression (YFP fluorescence) plotted as a function of time after rapamycin induction. (E) Exemplar IKs traces recorded in Chinese hamster ovary (CHO) cells co-expressing KCNQ1-YFP/KCNE1/nano-FKBP-FRB-Cα incubated 20 hr either without (left) or with (right) rapamycin. (F) Mean current densities in CHO cells co-expressing KCNQ1-YFP/KCNE1/nano-FKBP-FRB-Cα without rapamycin (black, n=10) or after 20 hr rapamycin incubation (red, n=14). ***p<0.001, paired t test. (G) Mean current densities in control cells co-expressing KCNQ1-YFP/KCNE1 without rapamycin (black, n=8) or after 20 hr rapamycin incubation (red, n=9).