Linking Phospholipase A2 to Phospholipid Turnover and Prostaglandin Synthesis inMast Cell Granules

摘要

A rapid PtdIns turnover has been observed in many receptor-mediated secretoryprocesses, including that of the mast cell. Although extensive publications have implicated a possible role of phospholipid turnover in the mechanism of signal transduction, many basic questions remain unanswered. Much of the confusion may have stemmed from the lack of information concerning the origin of the phospholipid pool undergoing rapid turnover, and our inclination to attribute most, if not all, phospholipid-related events to the cell membrane. For receptor-related phospholipid changes, the plasma membrane has usually been assumed to be the source. Since most studies of phospholipid turnover have been based on analysis of the whole cell or tissue extracts, identification of the subcellular compartment responsible for phospholipid turnover has been impossible. Furthermore, many experiments were carried out using cells permeabilized with detergent. In our experience with mast cells, detergent treatment alone initiates the exocytotic process without the need of any additional agonist or secretagogue.