Involvement of phospholipase D in store-operated calcium influx in vascular smooth muscle cells.
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.
Walter
M
M
Institut für Arterioskleroseforschung, Universität Münster, Germany. waltemi@uni-muenster.de
Tepel
M
M
Nofer
J R
JR
Neusser
M
M
Assmann
G
G
Zidek
W
W
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D007424:Intracellular Fluid / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D051381:Rats; D019284:Thapsigargin / Q000494:pharmacology
D010712:Phosphatidic Acids; D019284:Thapsigargin; D010739:Phospholipase D; D001920:Bradykinin; D002118:Calcium