Christiansen N O, Larsen C S, Esmann V
Department of Medicine and Infectious Diseases, Marselisborg Hospital, Aarhus C, Denmark.
Biochim Biophys Acta. 1988 Oct 7;971(3):317-24. doi: 10.1016/0167-4889(88)90147-4.
Accumulating evidence indicates that protein kinase C plays an essential role in the activation of NADPH oxidase. In the present study, the correlation between superoxide generation, intracellular calcium, activation of purified protein kinase C and stabilized membrane-bound protein kinase C was studied. Phorbol 12-myristate 13-acetate (PMA) and 1-deacyl-2-acetyl-rac-glycerol (OAG) were found to induce equal activation of purified protein kinase C and translocation of protein kinase C to the membrane fraction, but differed significantly in their ability to induce superoxide generation. Intracellular calcium was varied using calcium ionophores and increasing the intracellular calcium concentration to more than 1 microM was found to induce increased superoxide generation in maximally OAG-stimulated cells; this contrasted to maximally PMA-stimulated leukocytes. Ionomycin and A23187 were both found to induce a translocation of protein kinase C to the membrane fraction. This translocation was highly dependent upon extracellular calcium. In contrast, PMA- and OAG-induced translocation of protein kinase C was not dependent upon extracellular calcium. In conclusion, our results indicate that although PMA, OAG and calcium ionophores seem to activate protein kinase C in human polymorphonuclear leukocytes these activators differ in their ability to induce superoxide generation.
越来越多的证据表明，蛋白激酶C在烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的激活中起重要作用。在本研究中，对超氧化物生成、细胞内钙、纯化的蛋白激酶C的激活以及稳定的膜结合蛋白激酶C之间的相关性进行了研究。发现佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）和1-脱酰基-2-乙酰-消旋甘油（OAG）能诱导纯化的蛋白激酶C产生同等程度的激活以及蛋白激酶C向膜部分的转位，但它们诱导超氧化物生成的能力存在显著差异。使用钙离子载体改变细胞内钙，发现在最大程度受OAG刺激的细胞中，将细胞内钙浓度提高到超过1微摩尔可诱导超氧化物生成增加；这与最大程度受PMA刺激的白细胞形成对比。发现离子霉素和A23187均能诱导蛋白激酶C向膜部分转位。这种转位高度依赖细胞外钙。相比之下，PMA和OAG诱导的蛋白激酶C转位不依赖细胞外钙。总之，我们的结果表明，尽管PMA、OAG和钙离子载体似乎能激活人多形核白细胞中的蛋白激酶C，但这些激活剂在诱导超氧化物生成的能力上存在差异。
