ラットmast cellリン酸化反応に関する研究 (第8報)

―活性化mast cellよりのpolyphosphoinositide遊離とその局在―

抄録

Serosal mast cells were purified by bovine serum albumin density gradient centrifugation and prelabeled with ³²PO₄. Incorporation of ³²PO₄ into PPI, diphosphoinostide (DPI) and triphosphoinositide (TPI), was determined by thin-layer chromatography on oxalic acid impregnated silica gel plates. ³²PO₄ incorporation into DPI in mast cell supernates as well as pellets was increased by concanavalin A. As a control for possible artifactual formation of DPI in the supernates, supernates from labeled stimulated or unstimulated cells were incubated with intact or broken membrane granules from unlabeled cells isolated from sonicated mast cells on a Percoll gradient. No obvious ³²PO₄ incorporation into PPI in the granules was seen. The question of how much of the labeled PPI is present in the granule fraction was considered. Studies in unstimulated mast cells labeled with ³²PO₄, including controls for artifactual incorporation of label during granule isolation, suggest that at least 40% of the total cellular radiolabel in PPI is in the granules. The results of these studies indicate that changes in PPI metabolism may be a intrinsic part of the biochemical mechanisms that control mediator release from mast cells.