Activation of the leukocyte NADPH oxidase subunit p47phox by protein kinase C. A phosphorylation-dependent change in the conformation of the C-terminal end of p47phox.
Activation of the leukocyte NADPH oxidase subunit p47phox by protein kinase C. A phosphorylation-dependent change in the conformation of the C-terminal end of p47phox.
复制标题
蛋白激酶 C 激活白细胞 NADPH 氧化酶亚基 p47phox。p47phox C 末端构象的磷酸化依赖性变化。
DOI：
10.1021/bi9700936
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发表时间：
1997
期刊：
影响因子：
2.9
通讯作者：
Babior,BM
中科院分区：
文献类型：
--
作者：
Park,JW;Babior,BM
中性粒细胞的白细胞 NADPH 氧化酶是一种膜结合酶，利用 NADPH 作为电子供体催化氧气产生 O2-。该酶在静止的中性粒细胞中处于休眠状态，当细胞受到适当的刺激时，该酶就会获得催化活性。在激活过程中，胞质氧化酶成分 p47phox 和 p67phox 迁移到质膜，在那里它们与细胞色素 b558（一种膜结合黄素血蛋白）结合，组装活性氧化酶。激活过程的一个基本要素是 p47phox 的磷酸化，这是一种伴随整个细胞中氧化酶激活的事件，并且可以激活无细胞系统中的氧化酶。我们在此表明，p47phox 的磷酸化导致半胱氨酸 C378 对 N-乙基马来酰亚胺的反应性大幅降低，表明发生了涉及 p47phox C 端区域的构象变化。当 p47phoxis 暴露于花生四烯酸时，会发生类似的构象变化，花生四烯酸是激活无细胞系统中氧化酶的众多阴离子去污剂之一。我们认为这种构象变化导致了结合位点的出现，p47phox 在激活过程中通过该结合位点与细胞色素b558 相互作用。
The leukocyte NADPH oxidase of neutrophils is a membrane-bound enzyme that catalyzes the production of O2-from oxygen using NADPH as electron donor. Dormant in resting neutrophils, the enzyme acquires catalytic activity when the cells are exposed to appropriate stimuli. During activation, the cytosolic oxidase components p47phoxand p67phoxmigrate to the plasma membrane, where they associate with cytochromeb558, a membrane-bound flavohemoprotein, to assemble the active oxidase. An essential element of the activation process is the phosphorylation of p47phox, an event that accompanies oxidase activation in whole cells and can activate the oxidase in a cell-free system. We show here that the phosphorylation of p47phoxleads to a substantial decrease in the reactivity of cysteine C378 towardN-ethylmaleimide, indicating the occurrence of a conformational change involving the C-terminal region of p47phox. A similar conformational change occurs when p47phoxis exposed to arachidonate, one of a number of anionic detergents that activate the oxidase in the cell-free system. We propose that this change in conformation results in the appearance of a binding site through which p47phoxinteracts with cytochromeb558during the activation process.