Fig. 2. YM201636 directly inhibits human TPC2 channels.

a, b Representative current traces (a) and plot of the averaged dose response (b) of the inhibitory effect of YM201636 on the TPC2^PM Na⁺ currents elicited by 0.3 μM PI(3,5)P₂. Path-clamp recording was done in inside-out configuration using asymmetric Na⁺ (outside)/K⁺ (inside) recording solutions. The data (n = 6–8 for each data point) in (b) were fit by a Hill equation. c Representative current traces of the TPC2^PM Na⁺ currents recorded in inside-out configuration using symmetric Na⁺ recording solutions in the absence and presence of 50 nM or 0.2 µM YM201636. d Averaged inhibitory effects of YM201636 on the outward and inward TPC2^PM currents recorded at +80 and −80 mV as shown in (c). e, f Representative current traces (e) and averaged plot (f) of the effects of 1 µM YM201636 on 1 µM PI(3,5)P₂-induced TPC2 Na⁺ currents in whole lysosome patch-clamp recording using asymmetric K⁺ (cytosolic)/Na⁺ (lumenal) recording solutions. g, h Representative current traces (g) and averaged plot at −120 mV (h) of the effect of 1 µM YM201636 perfused on the extracellular side on TPC2^PM channel currents elicited by extracellularly applied TPC2-A1-N in whole cell patch-clamp recording using asymmetric Na⁺ (outside)/K⁺ (inside) recording solutions. The averaged data are presented as mean value ± SEM. Unpaired Student’s t-test (two tailed) was used to calculate p values. ** and ns are for p values ≤ 0.01 and > 0.05, respectively.