Connexin 43 connexon to gap junction transition is regulated by zonula occludens-1.
Connexin 43 connexon to gap junction transition is regulated by zonula occludens-1.
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DOI：
10.1091/mbc.e10-06-0548
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发表时间：
2011-05
影响因子：
3.3
通讯作者：
Gourdie RG
中科院分区：
文献类型：
--
作者：
Rhett JM;Jourdan J;Gourdie RG
Cx43 间隙连接 (GJ) 是哺乳动物心脏功能不可或缺的一部分。结果表明，ZO-1 动态调节 Cx43 连接子和 GJ 细胞间通道之间的转换，决定连接子介导的细胞通透性对 GJ 通讯的平衡。重要的是，我们发现了一个接近 GJ 的新结构域——perinexus。连接蛋白 43 (Cx43) 是一种间隙连接 (GJ) 蛋白，在哺乳动物组织中广泛表达，介导细胞间偶联。包含 GJ 聚集体的细胞间通道由配对连接子的对接形成，每个连接子由并列细胞贡献一个。小带闭塞-1 (ZO-1) 结合 Cx43 的羧基末端，我们之前已经证明，抑制 Cx43/ZO-1 相互作用可使 GJ 大小增加 48 小时。在这里，我们证明了 Cx43/ZO-1 破坏后 2 小时（~Cx43 半衰期）内 GJ 聚集发生增加。免疫沉淀和 Duolink 蛋白-蛋白相互作用测定表明，抑制作用的目标是 ZO-1 与 GJ 中的 Cx43 以及我们称为“perinexus”的相邻结构域中的连接子结合。与 GJ 大小的增加与连接子的减少相匹配，抑制 Cx43/ZO-1 降低了周膜相互作用的程度，增加了对接在 GJ 中的连接子相对于质膜中未对接连接子的比例，并增加了 GJ 细胞间通讯，同时降低了接触细胞而非非接触细胞中半通道介导的膜通透性。 ZO-1 小干扰 RNA 和过表达实验证实，ZO-1 功能的丧失和增强控制着连接子向 GJ 的转变。结论是，ZO-1 调节未对接的连接子聚集成 GJ 的速率，从而能够在质膜的连接域和近端非连接域之间动态分配 Cx43 通道功能。
Cx43 gap junctions (GJs) are integral to the function of the mammalian heart. It is shown that ZO-1 dynamically regulates the transition between Cx43 connexons and GJ intercellular channels, determining the balance of connexon-mediated cell permeability to GJ communication. Importantly, a novel domain proximal to GJs is identified—the perinexus. Connexin 43 (Cx43) is a gap junction (GJ) protein widely expressed in mammalian tissues that mediates cell-to-cell coupling. Intercellular channels comprising GJ aggregates form from docking of paired connexons, with one each contributed by apposing cells. Zonula occludens-1 (ZO-1) binds the carboxy terminus of Cx43, and we have previously shown that inhibition of the Cx43/ZO-1 interaction increases GJ size by 48 h. Here we demonstrated that increases in GJ aggregation occur within 2 h (∼Cx43 half-life) following disruption of Cx43/ZO-1. Immunoprecipitation and Duolink protein–protein interaction assays indicated that inhibition targets ZO-1 binding with Cx43 in GJs as well as connexons in an adjacent domain that we term the “perinexus.” Consistent with GJ size increases being matched by decreases in connexons, inhibition of Cx43/ZO-1 reduced the extent of perinexal interaction, increased the proportion of connexons docked in GJs relative to undocked connexons in the plasma membrane, and increased GJ intercellular communication while concomitantly decreasing hemichannel-mediated membrane permeance in contacting, but not noncontacting, cells. ZO-1 small interfering RNA and overexpression experiments verified that loss and gain of ZO-1 function govern the transition of connexons into GJs. It is concluded that ZO-1 regulates the rate of undocked connexon aggregation into GJs, enabling dynamic partitioning of Cx43 channel function between junctional and proximal nonjunctional domains of plasma membrane.