PI(4,5)P2 restored TRPM4 currents but not TRPM5 currents after their desensitization. (A) Typical time courses of the inside-out patch currents of WT rTRPM4 (left) or WT rTRPM5 (right) at +100 mV (filled circles) or −100 mV (open inverted triangles). The time of patch excisions were indicated by arrows. Twenty seconds after the patch excisions, 30 μM diC8-PI(4,5)P2 (water-soluble PI(4,5)P2) was applied (lower) or not applied (control, upper). The Ca2+ concentration of bath solutions (i.e., intracellular side, shaded bar) was 0.3 mM. At the end of measurements, the bath solution was changed to the Ca2+-free EGTA-containing solution (EGTA, hatched bar). (B) Ratios of the current amplitudes at 60 s after patch excision to the initial peak current amplitudes (I60 sec/Ipeak) at +100 mV in the absence (Control) or the presence (PI(4,5)P2) of 30 μM diC8-PI(4,5)P2 (n = 6–10). * p < 0.05 vs. Control. The current amplitudes of rTRPM4 in the presence of PI(4,5)P2 were 160% of the initial peak current amplitudes, but the current amplitudes of rTRPM5 in the presence of PI(4,5)P2 were negligible and similar to those in the absence of PI(4,5)P2.