Pochet Stéphanie, Métioui Mourad, Grosfils Katrina, Gómez-Muñoz Antonio, Marino Aida, Dehaye Jean-Paul
Laboratoire de Biochimie et de Biologie Cellulaire, Institut de Pharmacie CP 205/3, Campus Plaine, Université Libre de Bruxelles, Boulevard du Triomphe, B 1050 Brussels, Belgium.
Cell Signal. 2003 Jan;15(1):103-13. doi: 10.1016/s0898-6568(02)00059-1.
The muscarinic agonist carbachol stimulated phospholipase D (PLD) in rat submandibular gland (RSMG) ductal cells in a time and concentration-dependent manner. This effect was inhibited by chelation of extracellular calcium with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). PLD could also be activated by epinephrine and AlF(4)(-), two polyphosphoinositide-specific phospholipase C (PPI-PLC) activators, and by the phorbol ester o-tetradecanoylphorbol 13-acetate (TPA) which activates protein kinase C (PKC). Ionomycin and thapsigargin only slightly increased PLD activity. Ortho-vanadate, a tyrosine phosphatase inhibitor, also stimulated PLD activity. Both carbachol and o-vanadate increased the formation of inositol phosphates and the tyrosine phosphorylation of at least two proteins (55-60 and 120 kDa). Calphostin C (a PKC inhibitor), U73122 (a PPI-PLC inhibitor) and genistein (a tyrosine kinase inhibitor) blocked the activation of PLD, of PLC and the phosphorylation of tyrosyl residues in response to carbachol and vanadate. Taken together, these results suggest that rat submandibular gland ductal cells express a calcium-dependent PLD activity. This enzyme is regulated by carbachol via a PLC-PKC-tyrosine kinase pathway.
毒蕈碱激动剂卡巴胆碱以时间和浓度依赖性方式刺激大鼠下颌下腺（RSMG）导管细胞中的磷脂酶D（PLD）。用乙二醇双（β-氨基乙基醚）-N，N，N'，N'-四乙酸（EGTA）螯合细胞外钙可抑制这种效应。PLD也可被肾上腺素和AlF(4)(-)（两种多磷酸肌醇特异性磷脂酶C（PPI-PLC）激活剂）以及激活蛋白激酶C（PKC）的佛波酯十四烷酰佛波醇13-乙酸酯（TPA）激活。离子霉素和毒胡萝卜素仅轻微增加PLD活性。酪氨酸磷酸酶抑制剂原钒酸钠也刺激PLD活性。卡巴胆碱和原钒酸盐均增加肌醇磷酸的形成以及至少两种蛋白质（55 - 60 kDa和120 kDa）的酪氨酸磷酸化。钙磷蛋白C（一种PKC抑制剂）、U73122（一种PPI-PLC抑制剂）和染料木黄酮（一种酪氨酸激酶抑制剂）可阻断卡巴胆碱和钒酸盐引起的PLD、PLC激活以及酪氨酸残基的磷酸化。综上所述，这些结果表明大鼠下颌下腺导管细胞表达一种钙依赖性PLD活性。该酶通过PLC-PKC-酪氨酸激酶途径受卡巴胆碱调节。
