Fig. 4: Detection of single exocytosis events in INS-1 cells and hippocampal neuronal cells.
From: pHmScarlet is a pH-sensitive red fluorescent protein to monitor exocytosis docking and fusion steps
TIRF images of single-vesicle exocytosis in INS-1 cells expressing a VAMP2-pHmScarlet, c VAMP2-SEP, e VAMP2-pHuji, and h in HT-22 mouse hippocampal neuronal cells expressing VAMP2-pHmScarlet. Fusion events in a single cell are indicated by yellow rectangles (left top), scale bars: 2 μm. Time-lapses of the marked exocytotic events are shown on the bottom (1.3 × 1.3 µm), scale bars: 0.5 μm; normalized intensity traces of the marked events are highlighted as green or red channels (right top). Experiments were repeated five times for pHmScarlet in INS-1 cells (a) and three times in HT-22 cells (h), three times for SEP (c), and three times for pHuji (e) in INS-1 cells. ∆Fmax/F0 distribution of individual exocytotic events for vesicles labeled with (b) VAMP2-pHmScarlet, (d) VAMP2-SEP, and (f) VAMP2-pHuji. g Total number of exocytotic fusion events normalized to the cell area and imaging time, experiments were repeated three times (pHmScarlet: 11.7 ± 3.5, SEP: 12.4 ± 4.5, pHuji: 5.2 ± 2.8, pHmScarlet compared with pHuji, p = 0.0074; SEP compared with pHuji, p = 0.0045, two-sided Student’s t tests. Data are presented as mean ± SD, **p <0.01, ***p <0.001). Source data is provided as a source data file.
