Bauer H, Zweimueller-Mayer J, Steinbacher P, Lametschwandtner A, Bauer H C
Department of Organismic Biology, University of Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria.
J Biomed Biotechnol. 2010;2010:402593. doi: 10.1155/2010/402593. Epub 2010 Mar 9.
ZO (zonula occludens) proteins are scaffolding proteins providing the structural basis for the assembly of multiprotein complexes at the cytoplasmic surface of intercellular junctions. In addition, they provide a link between the integral membrane proteins and the filamentous cytoskeleton. ZO proteins belong to the large family of membrane-associated guanylate kinase (MAGUK)-like proteins comprising a number of subfamilies based on domain content and sequence similarity. Besides their structural function at cell-cell contacts, ZO proteins appear to participate in the regulation of cell growth and proliferation. Detailed molecular studies have shown that ZO proteins exhibit conserved functional nuclear localization and nuclear export motifs within their amino acid sequence. Further, ZO proteins interact with dual residency proteins localizing to the plasma membrane and the nucleus. Although the nuclear targeting of ZO proteins has well been described, many questions concerning the biological significance of this process have remained open. This review focuses on the dual role of ZO proteins, being indispensable structural components at the junctional site and functioning in signal transduction pathways related to gene expression and cell behavior.
闭锁小带（ZO）蛋白是一种支架蛋白，为多蛋白复合物在细胞间连接的细胞质表面组装提供结构基础。此外，它们在整合膜蛋白和丝状细胞骨架之间提供了一种联系。ZO蛋白属于膜相关鸟苷酸激酶（MAGUK）样蛋白的大家族，根据结构域含量和序列相似性可分为多个亚家族。除了在细胞间接触处的结构功能外，ZO蛋白似乎还参与细胞生长和增殖的调节。详细的分子研究表明，ZO蛋白在其氨基酸序列中表现出保守的功能性核定位和核输出基序。此外，ZO蛋白与定位于质膜和细胞核的双重定位蛋白相互作用。尽管ZO蛋白的核靶向作用已得到充分描述，但关于这一过程的生物学意义仍有许多问题尚未解决。本综述重点关注ZO蛋白的双重作用，它是连接位点不可或缺的结构成分，并在与基因表达和细胞行为相关的信号转导途径中发挥作用。
