Figure 4

The functional properties of the chimera drTRPM2-hNUD are similar to wild-type drTRPM2. (a) Representative whole-cell patch-clamp experiment of a HEK-293 cell expressing drTRPM2-hNUD. ADPR (1.2 mM) was infused into the cell through the patch pipette together with 1 µM Ca²⁺. Current onset occurs with a short delay after reaching whole-cell configuration (w.c.). Substitution of external Na⁺ in the standard bath solution (black bars) with the impermeable cation NMDG (gray bars) blocks the inward currents. (inset) Sketch of the chimera drTRPM2-hNUD containing the NUDT9H-domain of hTRPM2. For the exact procedure see Methods. (b) Same experiment as depicted in panel a but stimulation was performed by superfusion of the cells with standard bath solution containing 2-APB (1.5 mM; indicated with red bar). The pipette solution contained 1 µM Ca²⁺ without ADPR. (c) Same experiment as depicted in panel a but stimulation was performed with 0,15 mM 8-(3AP)-ADPR together with 1 µM Ca²⁺ in the pipette solution (d) Summary of the experiments shown in panel a–c as well as of experiments using H₂O₂ as the stimulus. All data are presented as mean ± s.e.m. Differences are significant at **(P < 0.01) and ****(P < 0.0001), evaluated with one-way ANOVA and the Bonferroni correction, n = 3–8. n.s., not significant.