Real-time Imaging of Inositol 1,4,5-trisphosphate Movement in Mouse Salivary Gland Cells

Inositol 1,4,5-trisphosphate () plays an important role in the release of from intracellular stores into the cytoplasm in a variety of cell types. translocation dynamics have been studied in response to many types of cell signals. However, the dynamics of cytosolic in salivary acinar cells are unclear. A green fluorescent protein (GFP)-tagged pleckstrin homology domain (PHD) was constructed and introduced into a phospholipase C (PLC ) transgenic mouse, and then the salivary acinar cells were isolated. GFP-PHD was heterogeneously localized at the plasma membrane and intracellular organelles in submandibular gland and parotid gland cells. Application of trypsin, a G protein-coupled receptor activator, to the two types of cells caused an increase in GFP fluorescence in the cell cytoplasm. The observed time course of trypsin-evoked movement in acinar cells was independent of cell polarity, and the fluorescent label showed an immediate increase throughout the cells. These results suggest that GFP-PHD in many tissues of transgenic mice, including non-cultured primary cells, can be used as a model for examination of intracellular dynamics.ope