Exocytosis timeline

The time progression of exocytotic events is determined by examining multiple indicator dyes in the linescan mode. In this mode a single line is repeatedly scanned through granules (dotted lines). The x-axis represents time. In the first example, a calcium indicator (blue) within the cells is used in conjunction with a granule pH sensor (red and green, LysoSensor). In the second example, an aqueous tracer (grayscale) is used (for determining when aqueous continuity is established between the granule interior and the extracellular fluid) in conjunction with the granule pH sensor (green and red, Acridine Orange).