FIGURE 2.

TPC2 targeted to the plasma membrane is uncoupled from ryanodine receptors. A–F, cytosolic Ca²⁺ signals from individual fura-2-loaded SKBR3 cells transiently transfected with C-terminally GFP-tagged TPC2 (black traces), TPC2ΔN (red traces), or GFP alone (green). A and B, responses to microinjection (arrowheads) with NAADP (10 nm) or buffer. Cells were incubated with trans-NED19 (100 nm, 15 min) as indicated. C and D, responses to microinjection of NAADP (10 nm) from untreated cells or cells incubated with ryanodine (10 μm, 15 min) or bafilomycin A₁ (1 μm, 60 min) as indicated. E, extracellular Ca²⁺ was removed 2–3 min before injection of NAADP. F, cells injected with cyclic ADP-ribose (cADPR, 500 nm). Results are means ± S.E. of the indicated number (n) of cells.