Multi-PDZ domain protein 1 (MUPP1) is concentrated at tight junctions through its possible interaction with claudin-1 and junctional adhesion molecule
Multi-PDZ domain protein 1 (MUPP1) is concentrated at tight junctions through its possible interaction with claudin-1 and junctional adhesion molecule
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DOI：
10.1074/jbc.m109005200
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发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Tsukita, S
中科院分区：
文献类型：
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作者：
Hamazaki, Y;Itoh, M;Tsukita, S
Claudins在其COOH末端大部分以valine结尾，构成紧密连接(TJ)链，这表明TJ链强烈吸引含有PDZ的蛋白质。事实上，ZO-1、-2和-3被证明直接与Claudins结合，每个ZO-1、-2和-3包含三个PDZ结构域。利用酵母双杂交系统，我们确定了ZO-1和MUPP1(多PDZ结构域蛋白1)是claudin-1的COOH末端的结合伙伴。MUPP1是一种含有13个PDZ结构域的蛋白质，但其结构特征尚未得到很好的描述。与重组MUPP1的体外结合实验证实了MUPP1与claudin-1的相互作用，并确定PDZ10是这种相互作用的负责结构域。获得了针对MUPP1的多克隆抗体。免疫荧光共聚焦显微镜和免疫电子显微镜显示，在极化的上皮细胞中，MUPP1仅集中在TJs。此外，体外结合和转染实验表明，另一种TJ黏附分子连接黏附分子也与MUPP1的PDZ9结构域结合。这些发现表明，MUPP1。它通过与Claudin和连接黏附分子结合，集中在上皮细胞的TJs，并可能作为一种多价支架蛋白，将各种蛋白质招募到TJs。
Claudins, most of which end in valine at their COOH termini, constitute tight junction (TJ) strands, suggesting that TJ strands strongly attract PDZ-containing proteins. Indeed, ZO-1, -2, and -3, each of which contains three PDZ domains, were shown to directly bind to claudins. Using the yeast two-hybrid system, we identified ZO-1 and MUPP1 (multi-PDZ domain protein 1) as binding partners for the COOH terminus of claudin-1. MUPP1 has been identified as a protein that contains 13 PDZ domains, but it has not been well characterized. In vitro binding assays with recombinant MUPP1 confirmed the interaction between MUPP1 and claudin-1 and identified PDZ10 as the responsible domain for this interaction. A polyclonal antibody specific for MUPP1 was then generated. Immunofluorescence confocal microscopy as well as immunoelectron microscopy with this antibody revealed that in polarized epithelial cells MUPP1 was exclusively concentrated at TJs. Furthermore, in vitro binding and transfection experiments showed that junctional adhesion molecule, another TJ adhesion molecule, also bound to the PDZ9 domain of MUPP1. These findings suggested that MUPP1. is concentrated at TJs in epithelial cells through its binding to claudin and junctional adhesion molecule and that it may function as a multivalent scaffold protein that recruits various proteins to TJs.