Domain-swapped Dimerization of the Second PDZ Domain of ZO2 May Provide a Structural Basis for the Polymerization of Claudins*
Domain-swapped Dimerization of the Second PDZ Domain of ZO2 May Provide a Structural Basis for the Polymerization of Claudins*
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DOI：
10.1074/jbc.m703826200
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发表时间：
2007-12
影响因子：
4.8
通讯作者：
Jiawen Wu;Yinshan Yang;Jiahai Zhang;P. Ji;W. Du;P. Jiang;D. Xie;Hongda Huang;Mian Wu;Guangzhao Zhang;Jihui Wu;Yunyu Shi
中科院分区：
文献类型：
--
作者：
Jiawen Wu;Yinshan Yang;Jiahai Zhang;P. Ji;W. Du;P. Jiang;D. Xie;Hongda Huang;Mian Wu;Guangzhao Zhang;Jihui Wu;Yunyu Shi
封闭小带蛋白（Zonula occludens proteins，ZO），包括ZO 1/2/3，是紧密连接相关蛋白。每个都包含三个PDZ域。已经证明，ZO 1可以通过第二PDZ结构域与ZO 2或ZO 3形成同源二聚体或异源二聚体。然而，其内在的结构基础并没有得到很好的理解。在这项研究中，第二PDZ结构域的ZO 2（ZO 2-PDZ 2）的溶液结构确定使用NMR光谱。结果表明，ZO蛋白中PDZ结构域通过三维结构域交换形成了一种新的二聚体模式，由于ZO蛋白中PDZ 2结构域之间的高度保守性，该模式可推广到ZO 1-PDZ 2或ZO 3-PDZ 2的同源二聚体以及ZO 1-PDZ 2/ZO 2-PDZ 2或ZO 1-PDZ 2/ZO 3-PDZ 2的异源二聚体。此外，GST下拉实验和免疫沉淀研究表明，ZO 1-PDZ 2和ZO 2-PDZ 2之间的相互作用和它们的自缔合确实存在于体外和体内。化学交联和动态激光光散射实验表明，ZO 1-PDZ 2和ZO 2-PDZ 2在溶液中均能形成低聚物。这种PDZ结构域介导的ZO寡聚化可以为封闭蛋白的聚合，即紧密连接的形成提供结构基础。
Zonula occludens proteins (ZOs), including ZO1/2/3, are tight junction-associated proteins. Each of them contains three PDZ domains. It has been demonstrated that ZO1 can form either homodimers or heterodimers with ZO2 or ZO3 through the second PDZ domain. However, the underlying structural basis is not well understood. In this study, the solution structure of the second PDZ domain of ZO2 (ZO2-PDZ2) was determined using NMR spectroscopy. The results revealed a novel dimerization mode for PDZ domains via three-dimensional domain swapping, which can be generalized to homodimers of ZO1-PDZ2 or ZO3-PDZ2 and heterodimers of ZO1-PDZ2/ZO2-PDZ2 or ZO1-PDZ2/ZO3-PDZ2 due to high conservation between PDZ2 domains in ZO proteins. Furthermore, GST pulldown experiments and immunoprecipitation studies demonstrated that interactions between ZO1-PDZ2 and ZO2-PDZ2 and their self-associations indeed exist both in vitro and in vivo. Chemical cross-linking and dynamic laser light scattering experiments revealed that both ZO1-PDZ2 and ZO2-PDZ2 can form oligomers in solution. This PDZ domain-mediated oligomerization of ZOs may provide a structural basis for the polymerization of claudins, namely the formation of tight junctions.