Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.
Department of Anatomy, Sapporo Medical University School of Medicine, Sapporo, Japan.
J Histochem Cytochem. 2020 Jan;68(1):59-72. doi: 10.1369/0022155419886263. Epub 2019 Oct 29.
Epithelial integrity and barrier function are maintained during cytokinesis in vertebrate epithelial tissues. The changes in localization and the roles of tricellular tight junction molecule lipolysis-stimulated lipoprotein receptor (LSR) during cytokinesis are not well known, although new tricellular tight junctions form at the flank of the midbody during cytokinesis. In this study, we investigated the changes in localization and the role of LSR at the midbody and centrosome during cytokinesis using human endometrial carcinoma cell line Sawano, comparing the tricellular tight junction molecule tricellulin; bicellular tight junction molecules occludin, claudin-7, zonula occludens-1, and cingulin; and the epithelial polarized related molecules apoptosis-stimulating of p53 protein 2, PAR3, and yes-associated protein. During cytokinesis induced by treatment with taxol, the epithelial barrier was maintained and the tricellular tight junction molecules LSR and tricellulin were concentrated at the flank of the acetylated tubulin-positive midbody and in γ-tubulin-positive centrosomes with the dynein adaptor Hook2, whereas the other molecules were localized there as well. All the molecules disappeared by knockdown using small interfering RNAs. Furthermore, by the knockdown of Hook2, the epithelial barrier was maintained and most of the molecules disappeared from the centrosome. These findings suggest that LSR may play crucial roles not only in barrier function but also in cytokinesis.
上皮细胞的完整性和屏障功能在脊椎动物上皮组织的胞质分裂过程中得以维持。尽管在胞质分裂过程中，新的三细胞紧密连接在中体的侧翼形成，但关于紧密连接分子脂解刺激脂蛋白受体（LSR）在胞质分裂过程中的定位变化及其作用仍知之甚少。在这项研究中，我们使用人子宫内膜癌细胞系 Sawano 研究了 LSR 在胞质分裂过程中的中体和中心体的定位变化及其作用，同时还研究了三细胞紧密连接分子tricellulin；双细胞紧密连接分子occludin、claudin-7、zonula occludens-1 和 cingulin；以及上皮极化相关分子 p53 蛋白凋亡刺激因子 2、PAR3 和 yes 相关蛋白。在用紫杉醇诱导的胞质分裂过程中，上皮屏障得以维持，三细胞紧密连接分子 LSR 和 tricellulin 集中在乙酰化微管阳性的中体侧翼和 γ-微管阳性的中心体中，与动力蛋白接头 Hook2 一起，而其他分子也定位在那里。所有分子均通过小干扰 RNA 敲低而消失。此外，通过 Hook2 的敲低，上皮屏障得以维持，并且大多数分子从中体消失。这些发现表明，LSR 不仅在屏障功能中而且在胞质分裂中都可能发挥关键作用。
