Figure 4.

Fusion events in which the center has a lower fluorescence than the surround. (A) Fusion occurred between 0 and 0.1 s. Below each image is the Vamp-GFP intensity (with background subtracted) averaged as a function of radial distance (r) away from the granule center. (B) A similar event to that in A occurred by 0.5 s (indicated by arrow) except that the center brighten at 0.3 s, consistent with the granule membrane flattening into the plane of the plasma membrane. Another fusion event occurs between 0.3 and 0.4 s (arrowhead) with bright center pixels. (C) Two fusion events occur between 0 and 0.5 s (arrows) with the centers of each dimmer than the surround. Both of these events were relatively long-lived (∼2 s). Note the different scales in B and C compared with A.