One contentious issue regarding pancreatic acinar exocytosis concerns which SNAP25 isoform (SNAP23/29/47) mediates the various fusion events in this cell type. Based on dominant-negative over-expression studies, SNAP23 was hypothesized to be the putative isoform mediating apical exocytosis, basolateral exocytosis, and ZG-ZG fusion. Unfortunately, using a SNAP23 KD mouse model, 80% SNAP23 KD was insufficient to manifest any secretion phenotype. A novel syncollin-pHluorin exocytosis imaging technique initially meant to assess which fusion events are perturbed by SNAP23 KD was successfully developed and displayed improvements over previous imaging techniques. The syncollin-pHluorin imaging enabled visualization of apical and basolateral exocytosis as well as sequential ZG-ZG fusions. Combined with spinning disk microscopy, this assay allows 3D live exocytosis imaging with high temporal and spatial resolution. This novel imaging assay will be useful in visualizing apical, basolateral, sequential, and lateral fusion events for future acinar studies.

One contentious issue regarding pancreatic acinar exocytosis concerns which SNAP25 isoform (SNAP23/29/47) mediates the various fusion events in this cell type. Based on dominant-negative over-expression studies, SNAP23 was hypothesized to be the putative isoform mediating apical exocytosis, basolateral exocytosis, and ZG-ZG fusion. Unfortunately, using a SNAP23 KD mouse model, 80% SNAP23 KD was insufficient to manifest any secretion phenotype. A novel syncollin-pHluorin exocytosis imaging technique initially meant to assess which fusion events are perturbed by SNAP23 KD was successfully developed and displayed improvements over previous imaging techniques. The syncollin-pHluorin imaging enabled visualization of apical and basolateral exocytosis as well as sequential ZG-ZG fusions. Combined with spinning disk microscopy, this assay allows 3D live exocytosis imaging with high temporal and spatial resolution. This novel imaging assay will be useful in visualizing apical, basolateral, sequential, and lateral fusion events for future acinar studies.