Liu B, Nakashima S, Takano T, Shimizu T, Nozawa Y
Department of Biochemistry, Gifu University School of Medicine, Japan.
Biochem Biophys Res Commun. 1995 Sep 14;214(2):418-23. doi: 10.1006/bbrc.1995.2303.
Protein kinase C (PKC) isozyme(s) involved in regulation of platelet-activating factor (PAF)-induced phospholipase D (PLD) activation was investigated in CHO cells stably expressing cloned guinea-pig PAF receptor (WT-H cells). Three PKC isozymes, alpha, epsilon, and zeta, were identified by Western blotting, which displayed different kinetics of translocation from cytosol to membrane upon PAF stimulation. Cytosolic PKC alpha was rapidly translocated to membrane in response to PAF within 30 s and then returned to cytosol by 10 min. This kinetics was well correlated with PAF-induced transient PLD activation. Pretreatment of the cells with 100 nM 4 beta-phorbol 12-myristate 13-acetate (PMA) for 2 h resulted in down-regulation of PKC alpha, leaving PKC epsilon and zeta unchanged. Under the same conditions, PAF and PMA-mediated PLD activation were markedly reduced. These data suggest that PKC alpha is involved in the regulation of PAF-stimulated PLD activation in WT-H cells.
在稳定表达克隆的豚鼠血小板激活因子（PAF）受体的CHO细胞（WT-H细胞）中，研究了参与调节PAF诱导的磷脂酶D（PLD）激活的蛋白激酶C（PKC）同工酶。通过蛋白质印迹法鉴定出三种PKC同工酶，α、ε和ζ，它们在PAF刺激后从胞质溶胶向膜的转位动力学不同。胞质溶胶中的PKCα在PAF刺激后30秒内迅速转位至膜，然后在10分钟内返回胞质溶胶。这种动力学与PAF诱导的瞬时PLD激活密切相关。用100 nM 4β-佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）预处理细胞2小时导致PKCα下调，而PKCε和ζ不变。在相同条件下，PAF和PMA介导的PLD激活明显降低。这些数据表明PKCα参与了WT-H细胞中PAF刺激的PLD激活的调节。
