Regulation of phospholipase D by P2X7 receptors in submandibular ductal cells.
ATP (1 mM) increased the phospholipase D (PLD) activity of rat submandibular gland (RSMG) ductal cells in a concentration-dependent and calcium-sensitive manner. The response to ATP was reproduced by benzoylbenzoyl-ATP (Bz-ATP, 100 microM) and also partly by adenosine 5'-(gamma-thio)triphosphate (ATPgammaS, 1 mM). A similar stimulation was observed in control mice (P2X7R+/+ mice) but not in mice lacking the P2X7 receptors (P2X7R-/- mice). Oxidized ATP and Coomassie blue or the addition of magnesium or nickel to the incubation medium inhibited the response to ATP. The stimulation of PLD by purinergic agonist was inhibited by about 50% by calphostin C and chelerythrine, two protein kinase C (PKC) inhibitors. The stimulation of PLD by Bz-ATP and by o-tetradecanoylphorbol 13-acetate (TPA), a phorbol ester which activates PKC, were not additive. From these results we can conclude that the activation of P2X7 receptors in RSMG ductal cells is coupled to the activation of a PLD. This activation is partly mediated by protein kinase C.
Pochet
Stéphanie
S
Laboratoire de Biochimie et de Biologie Cellulaire, Institut de Pharmacie C.P. 205/3, Campus Plaine, Université Libre de Bruxelles, Boulevard du Triomphe, Brussels B 1050, Belgium. spochet@ulb.ac.be
Gómez-Muñoz
Antonio
A
Marino
Aida
A
Dehaye
Jean-Paul
JP
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D020013:Calcium Signaling; D008297:Male; D051379:Mice; D010739:Phospholipase D / Q000378:metabolism*; D058910:Purinergic P2 Receptor Agonists; D051381:Rats; D017208:Rats, Wistar; D058486:Receptors, Purinergic P2X7; D013363:Submandibular Gland / Q000166:cytology / Q000201:enzymology*
C546469:P2rx7 protein, mouse; C546470:P2rx7 protein, rat; D058910:Purinergic P2 Receptor Agonists; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D010739:Phospholipase D