Department of Molecular Biology, University of Geneva, Switzerland.
Ann N Y Acad Sci. 2012 Jun;1257:125-32. doi: 10.1111/j.1749-6632.2012.06506.x.
Cingulin, paracingulin, and PLEKHA7 are proteins localized in the cytoplasmic region of the apical junctional complex of vertebrate epithelial cells. Cingulin has been detected at tight junctions (TJs), whereas paracingulin has been detected at both TJs and adherens junctions (AJs) and PLEKHA7 has been detected at AJs. One function of cingulin and paracingulin is to regulate the activity of Rho family GTPases at junctions through their direct interaction with guanidine exchange factors of RhoA and Rac1. Cingulin also contributes to the regulation of transcription of several genes in different types of cultured cells, in part through its ability to modulate RhoA activity. PLEKHA7, together with paracingulin, is part of a protein complex that links E-cadherin to the microtubule cytoskeleton at AJs. In this paper, we review the current knowledge about these proteins, including their discovery, the characterization of their expression, localization, structure, molecular interactions, and their roles in different developmental and disease model systems.
桥粒斑珠蛋白、副桥粒斑珠蛋白和 PLEKHA7 是定位于脊椎动物上皮细胞顶连接复合体胞质区域的蛋白质。桥粒斑珠蛋白已在紧密连接 (TJ) 中被检测到，而副桥粒斑珠蛋白已在 TJ 和黏着连接 (AJ) 中被检测到，PLEKHA7 则在 AJ 中被检测到。桥粒斑珠蛋白和副桥粒斑珠蛋白的一个功能是通过与 RhoA 和 Rac1 的鸟嘌呤核苷酸交换因子的直接相互作用来调节连接点处 Rho 家族 GTP 酶的活性。桥粒斑珠蛋白还通过调节 RhoA 活性来参与调节不同类型培养细胞中几种基因的转录。PLEKHA7 与副桥粒斑珠蛋白一起，构成了一个蛋白质复合物的一部分，该复合物将 E-钙黏蛋白连接到 AJ 处的微管细胞骨架上。本文综述了这些蛋白质的最新知识，包括它们的发现、表达、定位、结构、分子相互作用及其在不同发育和疾病模型系统中的作用。
