The arachidonic acid-binding protein S100A8/A9 promotes NADPH oxidase activation by interaction with p67phox and Rac-2
The arachidonic acid-binding protein S100A8/A9 promotes NADPH oxidase activation by interaction with p67phox and Rac-2
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DOI：
10.1096/fj.04-2377fje
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发表时间：
2005-01-01
期刊：
影响因子：
4.8
通讯作者：
Doussiere, J
中科院分区：
文献类型：
--
作者：
Kerkhoff, C;Nacken, W;Doussiere, J
钙离子和花生四烯酸结合的S100 A8/A9蛋白复合物最近被确定为吞噬细胞NADPH氧化酶的一个新的合作伙伴在体外研究。本研究通过特异性阻断S100 A9表达后嗜中性粒细胞样NB 4细胞和S100 A9（-/-）小鼠骨髓多形核中性粒细胞中氧化酶活性受损证明了其功能相关性。受损的氧化酶激活也可以模仿在无细胞系统中的中性粒细胞胞质溶胶与S100 A9特异性抗体的预处理。进一步的分析揭示了S100 A8/A9促进NADPH氧化酶活化的分子机制。体外氧化酶活化分析以及蛋白质-蛋白质相互作用研究表明，S100 A8是NADPH氧化酶复合物的优先相互作用伴侣，因为它与p67（phox）和Rac结合，而S100 A9既不与p67（phox）也不与p47（phox）相互作用。此外，S100 A8/A9将辅因子花生四烯酸转移到NADPH氧化酶，如突变体S100 A8/A9复合物不能结合花生四烯酸以增强NADPH氧化酶活性所示。结论S100 A8/A9在吞噬细胞NADPH氧化酶激活中起重要作用。
The Ca2+- and arachidonic acid-binding S100A8/A9 protein complex was recently identified by in vitro studies as a novel partner of the phagocyte NADPH oxidase. The present study demonstrated its functional relevance by the impaired oxidase activity in neutrophil-like NB4 cells, after specific blockage of S100A9 expression, and bone marrow polymorphonuclear neutrophils from S100A9(-/-) mice. The impaired oxidase activation could also be mimicked in a cell-free system by pretreatment of neutrophil cytosol with an S100A9-specific antibody. Further analyses gave insights into the molecular mechanisms by which S100A8/A9 promoted NADPH oxidase activation. In vitro analysis of oxidase activation as well as protein-protein interaction studies revealed that S100A8 is the privileged interaction partner for the NADPH oxidase complex since it bound to p67(phox) and Rac, whereas S100A9 did interact with neither p67phox nor p47(phox). Moreover, S100A8/A9 transferred the cofactor arachidonic acid to NADPH oxidase as shown by the impotence of a mutant S100A8/A9 complex unable to bind arachidonic acid to enhance NADPH oxidase activity. It is concluded that S100A8/A9 plays an important role in phagocyte NADPH oxidase activation.