Fig. 5: Kinetic observation of dissociation of Syt-1 clusters in the presence of Ca²⁺ in real-time.

A Frame-by-frame displays of the dissociation of Syt-1 clusters after flowing in Ca²⁺-containing buffer. Most clusters, including small (clusters #1 and #2) and large ones (#3, #4, and #5), dissociated in one image frame (n = 4). The interval between neighboring frames was 4 s. B Representative curves of the fluorescent intensity of Syt-1 clusters (red diamonds) or background (blue triangles) versus time showing the rapid dissociation of clusters of different sizes (left panel: small cluster; right panel: large cluster) simultaneously upon the entry of flow of Ca²⁺-containing buffer. The sharp decrease in background fluorescence was due to the flow of non-fluorescent buffer which diluted and replaced the original incubating buffer that contained fluorescent Syt-1.