FcγR-stimulated activation of the NADPH oxidase: phosphoinositide-binding protein p40phox regulates NADPH oxidase activity after enzyme assembly on the phagosome
FcγR-stimulated activation of the NADPH oxidase: phosphoinositide-binding protein p40phox regulates NADPH oxidase activity after enzyme assembly on the phagosome
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DOI：
10.1182/blood-2007-11-126029
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发表时间：
2008-11-01
期刊：
影响因子：
20.3
通讯作者：
Dinauer, Mary C.
中科院分区：
文献类型：
--
作者：
Tian, Wei;Li, Xing Jun;Dinauer, Mary C.
吞噬细胞NADPH氧化酶产生超氧化物以杀死微生物，并包括膜结合的黄细胞色素B（558）和细胞溶质p67（phox）、p47（phox）和p40（phox）亚基，这些亚基在细胞活化时进行膜移位。p40（phox）在静息细胞中结合p67（phox）的功能尚未完全了解。最近的研究表明，吞噬诱导的超氧化物的产生是由p40（phox）和它的结合磷脂酰肌醇-3磷酸（PI 3 P），磷酸肌醇丰富的膜内化吞噬体。为了更好地确定p40（phox）在Fc γ R诱导的氧化酶激活中的作用，我们使用了Fc γ R诱导的吞噬作用的免疫荧光和实时成像。YFP标记的p67（phox）和p40（phox）在吞噬体内化和PI 3 P探针积累之前易位到粒细胞吞噬体。p67（phox）和p47（phox）在新生和内化的吞噬体上的积累不需要p40（phox）或PI 3激酶活性，尽管在吞噬体密封之前和之后通过突变p40（phox）PI 3 P结合结构域或渥曼青霉素降低了超氧化物的产生。p40（phox）易位到新生的吞噬体需要结合p67（phox），而不是PI 3 P，虽然PI 3 P结合的损失减少了p40（phox）的保留后，吞噬体内化。我们的结论是，p40（phox）的功能主要是调节Fc γ R诱导的NADPH氧化酶活性，而不是组装，并刺激超氧化物的产生，通过PI 3 P信号增加后吞噬体内化。（血。2008; 112：3867-3877）
The phagocyte NADPH oxidase generates superoxide for microbial killing, and includes a membrane-bound flavocytochrome b(558) and cytosolic p67(phox), p47(phox), and p40(phox) subunits that undergo membrane translocation upon cellular activation. The function of p40(phox), which binds p67(phox) in resting cells, is incompletely understood. Recent studies showed that phagocytosis-induced superoxide production is stimulated by p40(phox) and its binding to phosphatidylinositol-3phosphate (PI3P), a phosphoinositide enriched in membranes of internalized phagosomes. To better define the role of p40(phox) in Fc gamma R-induced oxidase activation, we used immunofluorescence and real-time imaging of Fc gamma R-induced phagocytosis. YFP-tagged p67(phox) and p40(phox) translocated to granulocyte phagosomes before phagosome internalization and accumulation of a probe for PI3P. p67(phox) and p47(phox) accumulation on nascent and internalized phagosomes did not require p40(phox) or PI3 kinase activity, although superoxide production before and after phagosome sealing was decreased by mutation of the p40(phox) PI3P-binding domain or wortmannin. Translocation of p40(phox) to nascent phagosomes required binding to p67(phox) but not PI3P, although the loss of PI3P binding reduced p40(phox) retention after phagosome internalization. We conclude that p40(phox) functions primarily to regulate Fc gamma R-induced NADPH oxidase activity rather than assembly, and stimulates superoxide production via a PI3P signal that increases after phagosome internalization. (Blood. 2008; 112:3867-3877)