Kozawa O, Suzuki A, Kotoyori J, Tokuda H, Watanabe Y, Ito Y, Oiso Y
Department of Biochemistry, Institute for Developmental Research, Aichi Prefectural Colony, Japan.
J Cell Biochem. 1994 Jul;55(3):373-9. doi: 10.1002/jcb.240550315.
We previously reported that prostaglandin F2 alpha (PGF2 alpha) receptor is coupled to pertussis toxin (PTX)-sensitive GTP-binding protein (G protein) in osteoblast-like MC3T3-E1 cells [Miwa et al. (1990): Biochem Biophys Res Commun 171:1229-1235]. In the present study, we examined the effect of PGF2 alpha on the activation of phosphatidylcholine-hydrolyzing phospholipase D in MC3T3-E1 cells. PGF2 alpha stimulated the formation of choline in a dose-dependent manner in the range between 10 nM and 10 microM. The formation of choline was stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC)-activating phorbol ester. 4 alpha-Phorbol 12, 13-didecanoate, a PKC-nonactivating phorbol ester, had little effect on choline formation. The formation of choline stimulated by a combination of PGF2 alpha and TPA was additive. Staurosporine, an inhibitor for protein kinases, which inhibited the effect of TPA on choline formation, dose-dependently enhanced the formation of choline induced by PGF2 alpha. NaF, an activator of G protein, stimulated the formation of choline. The formation of choline stimulated by a combination of PGF2 alpha and NaF was not additive. NaF-induced formation of choline was dose-dependently enhanced by staurosporine. PTX dose-dependently inhibited the PGF2 alpha-induced formation of choline. These results strongly suggest that PGF 2 alpha activates phospholipase D independently from the activation of PKC in osteoblast-like cells and PTX-sensitive G protein is involved in the PGF2 alpha-induced phospholipase D activation.
我们先前报道过，在成骨样MC3T3-E1细胞中，前列腺素F2α（PGF2α）受体与百日咳毒素（PTX）敏感的GTP结合蛋白（G蛋白）偶联[Miwa等人（1990年）：《生物化学与生物物理研究通讯》171:1229-1235]。在本研究中，我们检测了PGF2α对MC3T3-E1细胞中磷脂酰胆碱水解磷脂酶D激活的影响。PGF2α在10 nM至10 μM范围内以剂量依赖性方式刺激胆碱的形成。胆碱的形成受到12-O-十四烷酰佛波醇-13-乙酸酯（TPA）的刺激，TPA是一种激活蛋白激酶C（PKC）的佛波酯。4α-佛波醇12,13-二癸酸酯，一种不激活PKC的佛波酯，对胆碱形成几乎没有影响。PGF2α和TPA联合刺激引起的胆碱形成是相加的。星形孢菌素是一种蛋白激酶抑制剂，它抑制TPA对胆碱形成的作用，但剂量依赖性地增强了PGF2α诱导的胆碱形成。NaF是一种G蛋白激活剂，刺激胆碱的形成。PGF2α和NaF联合刺激引起的胆碱形成不是相加的。星形孢菌素剂量依赖性地增强了NaF诱导的胆碱形成。PTX剂量依赖性地抑制PGF2α诱导的胆碱形成。这些结果强烈表明，在成骨样细胞中，PGF2α独立于PKC的激活而激活磷脂酶D，并且PTX敏感的G蛋白参与PGF2α诱导的磷脂酶D激活。
