Effects of PI injection in oocytes expressing XtTPC3. (A) Representative current traces in the PI injection experiments. The protocol to obtain the two parameters at 50 mV and 100 mV (top), and representative current traces injected with water (middle) or 0.2 mM PI(3,4)P2 (bottom) are shown. For each injection, the traces before injection (black; 0 s), after injection (red; 700 s) and after an induction stimulus (blue; 800 s) are shown. (B) Time courses of the effects of 0.2-mM PI injection on time constants of activation at 100 mV (top) and the amplitude of inward currents (bottom). PIs or water were injected after the second pulse. After the eighth pulse, the 80-mV depolarization stimulus was given twice for 10 s to fully induce XtTPC3. The current amplitude at each time was normalized by that after induction. The points of injection and induction are indicated by black arrows. The colors of the circles above the plots correspond to those in A. (C) Time constants of activation at 100 mV before injection (black; 0 s) and after injection (red; 700 s) for each type of injected PI. (D) The normalized amplitudes elicited by 50 mV at 700 s for each type of injected PI. Error bars represent the SD of five independent experiments. *, P < 0.05; **, P < 0.01.
