Inositol 1,4,5-trisphosphate (IP₃) plays an important role in the release of Cα²+ from intracellular stores into the cytoplasm in a variety of cell types. IP₃ translocation dynamics have been studied in response to many types of cell signals. However, the dynamics of cytosolic IP₃ in salivary acinar cells are unclear. A green fluorescent protein (GFP)-tagged pleckstrin homology domain (PHD) was constructed and introduced into a phospholipase C δ1 (PLC δ1) 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 IP₃movement 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 IP₃intracellular dynamics.

• Dong Min Shin(Department of Oral Biology, Brain Korea 21 Project, Oral Science Research Center, Center for Natural Defense System, Yonsei University College of Dentistry) Corresponding author
• Jeong Hee Hong(Department of Oral Biology, Brain Korea 21 Project, Oral Science Research Center, Center for Natural Defense System, Yonsei University College of Dentistry)
• Syng-Ill Lee(Department of Oral Biology, Brain Korea 21 Project, Oral Science Research Center, Center for Natural Defense System, Yonsei University College of Dentistry)