Figure 4.

PIP₂ responses of WT and MHR1/2 domain mutant nvTRPM2 channels. (A–G) Macroscopic inside-out patch currents activated by 3.2 mM ADPR (gray bars) + 125 µM Ca²⁺ (long black bars) in the absence or presence of added 2.5 or 25 µM dioctanoyl-PIP₂ (short black bars) for WT (A), T143A (B), R271A (C), T307A (D), R329A (E), T179A (F), and Y264A (G) nvTRPM2. (H) Fractional activation of WT and mutant nvTRPM2 channels by 2.5 and 25 µM PIP₂ (color coding follows construct labeling in A–G). Currents in 2.5 or 25 µM PIP₂ were normalized to those obtained without added PIP₂ in the same patch. Data represent mean ± SEM from three or four independent experiments.