Fig. 4.

NAADP stimulates single channel activity of TPC2 rerouted to the plasma membrane.

A, exemplar single channel recordings from inside-out patches excised from HEK cells expressing plasma membrane-targeted TPC2 in response to the indicated concentrations of NAADP. Na⁺ was the charge carrier and the holding potential was +40 mV. C denotes the closed state.

B, summary data quantifying open probability (NP_o; n = 3–28).

C, current-voltage relationships derived from records similar to those shown in A (n = 3).

D, exemplar open and closed time distributions at the indicated NAADP concentration.

E, summary data quantifying mean open time (n = 3–28).

F, likely gating schemes for TPC2.