Rho is involved in superoxide formation during phagocytosis of opsonized zymosans
Rho is involved in superoxide formation during phagocytosis of opsonized zymosans
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DOI：
10.1074/jbc.m308386200
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发表时间：
2004-05-14
影响因子：
4.8
通讯作者：
Park, JB
中科院分区：
文献类型：
--
作者：
Kim, JS;Diebold, BA;Park, JB
吞噬作用伴随着NADPH氧化酶复合物产生超氧化物，其中gtp结合的Rac是必不可少的。我们想确定Rho是否也参与了吞噬过程中超氧化物的产生。Tat-C3外酶（Tat-C3）对Rho的抑制阻断了超氧化物的形成，并减少了血清- (SOZ)、C3bi- (COZ)和IgG-opsonized zymosan （IOZ）颗粒的吞噬。在对肉豆蔻酸酯佛波酯（PMA）、甲酰基Met-Leu-Phe （fMLP）或巨噬细胞集落刺激因子（M-CSF）的反应中，塔特- c3不影响超氧化物的形成。转染了表达RhoA显性阴性形式（N19RhoA）的cDNA的J774细胞也减少了超氧化物的形成。然而，纯化的烯酰化重组RhoA在体外没有激活NADPH氧化酶，这表明Rho不直接与NADPH氧化酶相互作用。Tat-C3对RhoA活性有抑制作用，对Rac活性无影响。它还抑制了p47（PHOX）的磷酸化，PHOX是NADPH氧化酶的细胞质成分之一。综上所述，这些结果表明，在SOZ、COZ和IOZ的吞噬过程中，Rho通过磷酸化p47（PHOX）在超氧化物形成中起重要作用。
Phagocytosis is accompanied by the production of superoxide by the NADPH oxidase complex, for which GTP-bound Rac is essential. We wanted to determine whether Rho is also involved in the production of superoxide during phagocytosis. Inhibition of Rho by Tat-C3 exoenzyme (Tat-C3) blocked superoxide formation and curtailed the phagocytosis of serum- (SOZ), C3bi- (COZ), and IgG-opsonized zymosan (IOZ) particles. Tat-C3 did not affect superoxide formation in response to phorbol myristate acetate (PMA), formyl Met-Leu-Phe ( fMLP), or macrophage colony-stimulating factor (M-CSF). Superoxide formation was also reduced in J774 cells transfected with a cDNA expressing dominant-negative form of RhoA ( N19RhoA). However, purified prenylated recombinant RhoA did not activate NADPH oxidase in vitro, suggesting that Rho does not interact directly with NADPH oxidase. Tat-C3 inhibited the activity of RhoA, but did not affect that of Rac in vitro or in vivo. It also inhibited the phosphorylation of p47(PHOX), one of the cytosolic components of NADPH oxidase. Taken together, these results suggest that Rho plays an important role in superoxide formation during phagocytosis of SOZ, COZ, and IOZ via phosphorylation of p47(PHOX).