Small-angle X-ray scattering reveals an extended organization for the autoinhibitory resting state of the p47phox modular protein
Small-angle X-ray scattering reveals an extended organization for the autoinhibitory resting state of the p47phox modular protein
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DOI：
10.1021/bi060274k
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发表时间：
2006-06-13
期刊：
影响因子：
2.9
通讯作者：
Fieschi, Franck
中科院分区：
文献类型：
--
作者：
Durand, Dominique;Cannella, Dominique;Fieschi, Franck
在对微生物感染的反应中，中性粒细胞促进NADPH氧化酶复合物的组装，以产生超氧阴离子。胞质因子p47（phox）、p67（phox）、p40（phox）和小G蛋白Rac与膜质异二聚体黄细胞色素b(558)（由gp91（phox）和p22（phox）组成）的结合激活了该反应。在激活过程中，p47（phox）作为磷酸化的靶标和作为支架蛋白指导细胞质因子的易位和组装到膜组分上起着核心作用。p47（phox）的PX和串联SH3s分别被强调为与膜脂和p22（phox）组分相互作用的关键决定因素。在静息状态下，两个相应的界面被认为是被掩盖的，允许其细胞质定位。然而，p47（phox）的静息状态模块组织及其自抑制模式仍未完全了解，尽管有关于单独模块的结构信息。更准确地说，它提出了PX结构域和串联SH3结构域在静息状态下相互排列的问题。为了解决这个问题，我们利用小角度x射线散射对溶液中的整个p47（phox）分子进行了研究。尽管存在内部的自抑制相互作用，p47（phox）采用扩展构象。首次对整个p47（phox）结构域的排列有了深入的了解。我们的数据允许抛弃通常的球形和紧凑的自抑制静息状态的表示。
In response to microbial infection, neutrophiles promote the assembly of the NADPH oxidase complex in order to produce superoxide anions. This reaction is activated by the association of cytosolic factors, p47(phox), p67(phox), p40(phox), and a small G protein Rac with the membranous heterodimeric flavocytochrome b(558), composed of gp91(phox) and p22(phox). In the activation process, p47(phox) plays a central role as the target of phosphorylations and as a scaffolding protein conducting the translocation and assembly of cytosolic factors onto the membranous components. The PX and tandem SH3s of p47(phox) have been highlighted as being key determinants for the interaction with membrane lipids and the p22(phox) component, respectively. In the resting state, the two corresponding interfaces are thought to be masked allowing its cytoplasmic localization. However, the resting state modular organization of p47(phox) and its autoinhibition mode are still not fully understood despite available structural information on separate modules. More precisely, it raises the question of the mutual arrangement of the PX domain and the tandem SH3 domains in the resting state. To address this question, we have engaged a study of the entire p47(phox) molecule in solution using small-angle X-ray scattering. Despite internal autoinhibitory interactions, p47(phox) adopts an extended conformation. First insights about the domain arrangement in whole p47(phox) can be derived. Our data allow to discard the usual representation of a globular and compact autoinhibited resting state.