FIGURE 5.

N-Glycosylation of TPC1 regulates NAADP-mediated Ca²⁺ release. A, confocal fluorescence images of HEK (left) or SKBR3 (right) cells expressing wild-type TPC1-GFP or TPC1^3QGFP. In B, cells were contransfected with wild-type TPC1-mRFP and TPC1^3QGFP. Merged images are shown to the right. Scale bars, 5 μm. C, cytosolic Ca²⁺ signals from individual fura-2-loaded SKBR3 cells microinjected (arrowheads) with 10 nm NAADP (black lines) or buffer (red lines). Cells were either mock-transfected or transiently transfected with TPC1-GFP or TPC1^3QGFP. Summary results quantifying amplitudes of the Ca²⁺ signals in individual cells (means ± S.E. of 4–6 cells) from the indicated cells are shown in the last panel.