FIGURE 7.
Ned-19 potentiates the effects of NAADP at TPC2. a, Ned-19 can activate TPC2 in the absence of NAADP. A typical experiment is shown where Ned-19 (100 nm) activates TPC2 in the absence of NAADP. Subsequent addition of NAADP potentiates the effects of Ned-19 (further evidence that NAADP and Ned-19 do not compete for the same binding sites). Washout of cytosolic NAADP and Ned-19 (bottom trace) lowers Po but to a level higher than that of the control (top trace). This is because although Ned-19 binding to TPC2 is reversible, NAADP binding to TPC2 is irreversible. b, comparison of the individual and simultaneous effects of NAADP and Ned-19 on TPC2 Po (*, p < 0.05).