Translocation of Rac correlates with NADPH oxidase activation. Evidence for equimolar translocation of oxidase components.
Translocation of Rac correlates with NADPH oxidase activation. Evidence for equimolar translocation of oxidase components.
复制标题
DOI：
10.1016/s0021-9258(19)36882-6
复制
发表时间：
1993-10
期刊：
影响因子：
--
通讯作者：
Mark T. Quinn;T. Evans;L. R. Loetterle;A. J. Jesaitis;G. Bokoch
中科院分区：
文献类型：
--
作者：
Mark T. Quinn;T. Evans;L. R. Loetterle;A. J. Jesaitis;G. Bokoch
人嗜中性粒细胞的产生超氧化物的NADPH氧化酶系统的激活涉及几种嗜中性粒细胞组分的组装，一些位于质膜上，另一些位于胞质溶胶中。最近已经确定NADPH氧化酶活性所需的组分之一是GTP结合蛋白Rac。为了进一步研究Rac在NADPH氧化酶系统中的作用，进行了研究以确定其在静息和活化的人嗜中性粒细胞中的亚细胞分布。在静息细胞中，Rac和相关的鸟嘌呤核苷酸调节因子GDP解离抑制因子（GDI）仅位于胞质溶胶中，与其他已知的氧化酶因子p47-phox和p67-phox一起沿着。用佛波醇12-肉豆蔻酸酯13-乙酸酯或甲酰-甲硫氨酰-亮氨酰-苯丙氨酸激活中性粒细胞后，Rac从胞质溶胶易位到质膜，这种易位在时间上与p47-phox和p67-phox的易位以及超氧化物的产生相对应。GDI仍然定位于胞质溶胶，这表明参与Rac易位前的Rac-GDI复合物的解离的氧化酶的激活。与质膜相关的胞质因子的量的测定表明，Rac，p47-phox，和p67-phox以等摩尔量同时易位到质膜，但膜相关的细胞色素B是在3-4倍摩尔过量。这些发现表明，Rac可能在组装活性NADPH氧化酶复合物中发挥作用。
Activation of the superoxide-generating NADPH oxidase system of human neutrophils involves the assembly of several neutrophil components, some located on the plasma membrane and others in the cytosol. It has recently been established that one of the required components for NADPH oxidase activity is the GTP-binding protein Rac. To further investigate the role of Rac in the NADPH oxidase system, studies were carried out to determine its subcellular distribution in resting and activated human neutrophils. In resting cells, Rac and an associated guanine nucleotide regulatory factor, GDP dissociation inhibitor (GDI), were located only in the cytosol, along with other known oxidase factors, p47-phox and p67-phox. After activation of neutrophils with phorbol 12-myristate 13-acetate or formyl-methionyl-leucyl-phenylalanine, Rac was translocated from the cytosol to the plasma membrane, and this translocation corresponded temporally with the translocation of p47-phox and p67-phox and with the generation of superoxide. GDI remained localized to the cytosol, suggesting activation of the oxidase involved dissociation of the Rac-GDI complex prior to Rac translocation. Determination of the quantities of cytosolic factors associated with the plasma membrane indicated that Rac, p47-phox, and p67-phox are translocated to the plasma membrane simultaneously in equimolar amounts, but that the membrane-associated cytochrome b was present at 3-4-fold molar excess. These findings suggest that Rac may play a role in assembly of the active NADPH oxidase complex.