Similar and Distinct Properties of MUPP1 and Patj, Two Homologous PDZ Domain-Containing Tight-Junction Proteins
Similar and Distinct Properties of MUPP1 and Patj, Two Homologous PDZ Domain-Containing Tight-Junction Proteins
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DOI：
10.1128/mcb.01505-08
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发表时间：
2009-05-01
影响因子：
5.3
通讯作者：
Tsukita, Shoichiro
中科院分区：
文献类型：
--
作者：
Adachi, Makoto;Hamazaki, Yoko;Tsukita, Shoichiro
MUPP1和PatJ都由一个L27结构域和多个PDZ结构域(分别为13和10个结构域)组成，并定位于上皮细胞的紧密连接(TJ)。虽然已知PATJ负责TJ的组织和上皮的极性，但缺乏MUPP1的特征。在这项研究中，我们发现MUPP1和PatJ共享几个结合伙伴，包括JAM1、ZO-3、Pals1、Par6和Nectins(粘附点上的细胞-细胞黏附分子)。MUPP1和PatJ表现出相似的亚细胞分布，它们定位于TJ的机制似乎也重叠。尽管有这些相似之处，但功能研究表明，PatJ对于TJ的建立和上皮极化是不可或缺的，而MUPP1不是。因此，尽管MUPP1和PatJ有几个共同的分子性质，但它们的功能完全不同。我们提出的证据表明，Pals1对PATJ的亲和力高于对MUPP1的亲和力，并参与了Par6-aPKC复合体的激活，对PATJ在上皮细胞中的功能具有重要作用。
MUPP1 and Patj are both composed of an L27 domain and multiple PDZ domains (13 and 10 domains, respectively) and are localized to tight junctions (TJs) in epithelial cells. Although Patj is known to be responsible for the organization of TJs and epithelial polarity, characterization of MUPP1 is lacking. In this study, we found that MUPP1 and Patj share several binding partners, including JAM1, ZO-3, Pals1, Par6, and nectins (cell-cell adhesion molecules at adherens junctions). MUPP1 and Patj exhibited similar subcellular distributions, and the mechanisms with which they localize to TJs also appear to overlap. Despite these similarities, functional studies have revealed that Patj is indispensable for the establishment of TJs and epithelial polarization, whereas MUPP1 is not. Thus, although MUPP1 and Patj share several molecular properties, their functions are entirely different. We present evidence that the signaling mediated by Pals1, which has a higher affinity for Patj than for MUPP1 and is involved in the activation of the Par6-aPKC complex, is of principal importance for the function of Patj in epithelial cells.