Regulation of exocytosis via release of Ca2+ from intracellular stores

✍ Scribed by Frederick W. Tse; Amy Tse

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 70 KB
• Volume: 21
• Category: Article
• ISSN: 0265-9247
• DOI: 10.1002/(sici)1521-1878(199910)21:10<861::aid-bies8>3.0.co;2-9

✦ Synopsis

The release of Ca 2ϩ from intracellular stores is an important trigger for secretion in many cell types. Depending on the spatial relationship between the intracellular Ca 2ϩ stores and the site of exocytosis, the Ca 2ϩ signal can be very local or spread throughout the entire cell. Here, we review how the release of Ca 2ϩ from inositol trisphospate (IP 3 )-sensitive stores contributes differently to the stimulus-secretion coupling in three types of secretory cells (acinar cells of the pancreas, gonadotrophs, and corticotrophs of the anterior pituitary gland). We propose that in both pancreatic acinar cells and pituitary gonadotrophs the IP 3 -sensitive stores may be in close proximity to the sites of exocytosis such that the concentration of Ca 2ϩ at these sites are transiently much higher than the average cytosolic Ca 2ϩ concentration. In contrast, the local Ca 2ϩ gradient is less prominent in pituitary corticotrophs. Finally, some recent technical developments that may contribute significantly to future investigations of local Ca 2ϩ signals are discussed.