Involvement of phospholipase D in store‐operated calcium influx in vascular smooth muscle cells

[摘要]

In non-excitable cells, sustained intracellular Ca²⁺ increase critically depends on influx of extracellular Ca²⁺. Such Ca²⁺ influx is thought to occur by a ‘store-operated’ mechanism, i.e. the signal for Ca²⁺ entry is believed to result from the initial release of Ca²⁺ from inositol 1,4,5-trisphosphate-sensitive intracellular stores. Here we show that the depletion of cellular Ca²⁺ stores by thapsigargin or bradykinin is functionally linked to a phosphoinositide-specific phospholipase D (PLD) activity in cultured vascular smooth muscle cells (VSMC), and that phosphatidic acid formed via PLD enhances sustained calcium entry in this cell type. These results suggest a regulatory role for PLD in store-operated Ca²⁺ entry in VSMC.

[学科分类] 生物化学/生物物理

[关键词] Calcium;Phospholipase D;Signal transduction;Thapsigargin;Bradykinin;Phosphatidylinositol;Phosphatidylcholine;[Ca2+]i;intracellular free calcium concentration;DG;1;2-diacylglycerol;InsP3;inositol 1;4;5-trisphosphate;PA;phosphatidic acid;PBS;phosphate-buffered saline;PBut;phosphatidylbutanol;PC;phosphatidylcholine;PLC;phospholipase C;PLD;phospholipase D;PIP2;phosphatidylinositol 4;5-bisphosphate;PIP;phosphatidylinositol 4-monophosphate;PI;phosphatidylinositol;VSMC;vascular smooth muscle cells