14-3-3 Protein Regulates Cell Adhesion in the Seminiferous Epithelium of Rat Testes
14-3-3 Protein Regulates Cell Adhesion in the Seminiferous Epithelium of Rat Testes
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DOI：
10.1210/en.2009-0427
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发表时间：
2009-10-01
期刊：
影响因子：
4.8
通讯作者：
Cheng, C. Yan
中科院分区：
文献类型：
--
作者：
Wong, Elissa W. P.;Sun, Shengyi;Cheng, C. Yan
极性蛋白参与调节和维持上皮细胞的紧密连接（TJ）和细胞极性。在这里，我们报告了 14-3-3 theta，它是哺乳动物细胞中秀丽隐杆线虫 Par5 的同源物，已知它在 TJ 处赋予细胞极性，它发现于顶端外质特化 (ES)，这是一种仅限于支持细胞延长精子细胞界面的睾丸特异性粘附连接类型，其中 TJ 不存在。 14-3-3 theta 在赋予顶端 ES 细胞粘附方面发挥着关键作用。在精子形成前，在生精上皮中检测到顶端 ES 的 14-3-3 theta 表达缺失。在体外培养的支持细胞中，RNA 干扰可抑制 14-3-3 theta 参与支持细胞粘附，该细胞具有模拟体内血睾屏障 (BTB) 的 TJ 通透性屏障。在支持细胞中 14-3-3 theta 敲低后，观察到 N-cadherin 和 zonula occlusionns-1 的错误定位，但不是 α- 和 β-catenin，从细胞-细胞界面移动到细胞质，表明细胞粘附破坏。内吞作用测定的研究表明，这种细胞粘附的丧失是由 BTB 处 N-钙粘蛋白和连接粘附分子 A 的内吞动力学增加介导的，这可能代表极性蛋白调节细胞粘附的一般机制。总之，睾丸利用 14-3-3 theta 调节顶端 ES 处的细胞粘附以促进精子形成，并利用 BTB 处的细胞粘附以促进上皮周期第 VIII-IX 阶段的前细线期精母细胞的转运。 14-3-3 theta 可能充当分子开关，在精子发生过程中协调生精上皮中的这两个细胞事件。 （内分泌学 150：4713-4723，2009）
Polarity proteins have been implicated in regulating and maintaining tight junction (TJ) and cell polarity in epithelia. Here we report 14-3-3 theta, the homolog of Caenorhabditis elegans Par5 in mammalian cells, which is known to confer cell polarity at TJ, is found at the apical ectoplasmic specialization (ES), a testis-specific adherens junction type restricted to the Sertoli cell-elongating spermatid interface, in which TJ is absent. 14-3-3 theta was shown to play a critical role in conferring cell adhesion at the apical ES. A loss of 14-3-3 theta expression at the apical ES was detected in the seminiferous epithelium before spermiation. Involvement of 14-3-3 theta in Sertoli cell adhesion was confirmed by its knockdown by RNA interference in Sertoli cells cultured in vitro with established TJ permeability barrier that mimicked the blood-testis barrier (BTB) in vivo. Mislocalization of N-cadherin and zonula occludens-1, but not alpha- and beta-catenins, was observed after 14-3-3 theta knockdown in Sertoli cells, moving from the cell-cell interface to cytosol, indicating a disruption of cell adhesion. Studies by endocytosis assay illustrated that this loss of cell adhesion was mediated by an increase in the kinetics of endocytosis of N-cadherin and junctional adhesion molecule-A at the BTB, which may represent a general mechanism by which polarity proteins regulate cell adhesion. In summary, the testis is using 14-3-3 theta to regulate cell adhesion at the apical ES to facilitate spermiation and at the BTB to facilitate the transit of preleptotene spermatocytes at stages VIII-IX of the epithelial cycle. 14-3-3 theta may act as a molecular switch that coordinates these two cellular events in the seminiferous epithelium during spermatogenesis. (Endocrinology 150: 4713-4723, 2009)