A PKA-ezrin-Cx43 signaling complex controls gap junction communication and thereby trophoblast cell fusion
A PKA-ezrin-Cx43 signaling complex controls gap junction communication and thereby trophoblast cell fusion
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DOI：
10.1242/jcs.149609
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发表时间：
2014-10-01
影响因子：
4
通讯作者：
Tasken, Kjetil
中科院分区：
文献类型：
--
作者：
Pidoux, Guillaume;Gerbaud, Pascale;Tasken, Kjetil
细胞融合作为某些细胞类型分化的一部分而发生，包括肌肉中的肌管和重塑骨中的破骨细胞。在人胎盘中，单核细胞滋养层在人绒毛膜促性腺激素（hCG）驱动的过程中融合形成多核合胞体，使母体和胎儿循环之间的营养物质和气体交换。蛋白激酶A（PKA）从A-激酶锚定蛋白（AKAP）中被置换的实验，或者通过siRNA介导的敲除来消除特定AKAP的实验，指出埃兹蛋白作为hCG、cAMP和PKA介导的融合过程调节所需的支架。通过各种免疫沉淀和免疫定位实验，我们表明ezrin指导PKA连接蛋白43（Cx43，也称为GJA 1）和闭合蛋白-1（ZO-1，也称为TJP 1）的分子复合物。敲除实验和重建与ezrin或Cx43与或不与其相互作用的合作伙伴或PKA的能力的组合表明，ezrin介导的协调PKA和Cx43的本地化是必要的离散控制Cx43磷酸化和hCG刺激的间隙连接通讯，触发细胞滋养层细胞融合。
Cell fusion occurs as part of the differentiation of some cell types, including myotubes in muscle and osteoclasts in remodeling bone. In the human placenta, mononuclear cytotrophoblasts in a human chorionic gonadotropin (hCG)-driven process fuse to form multinucleated syncytia that allow the exchange of nutrients and gases between the maternal and fetal circulation. Experiments in which protein kinase A (PKA) is displaced from A-kinase anchoring proteins (AKAPs), or in which specific AKAPs are depleted by siRNA-mediated knockdown, point to ezrin as a scaffold required for hCG-, cAMP-and PKA-mediated regulation of the fusion process. By a variety of immunoprecipitation and immunolocalization experiments, we show that ezrin directs PKA to a molecular complex of connexin 43 (Cx43, also known as GJA1) and zona occludens-1 (ZO-1, also known as TJP1). A combination of knockdown experiments and reconstitution with ezrin or Cx43 with or without the ability to bind to its interaction partner or to PKA demonstrate that ezrin-mediated coordination of the localization of PKA and Cx43 is necessary for discrete control of Cx43 phosphorylation and hCG-stimulated gap junction communication that triggers cell fusion in cytotrophoblasts.