Zonula occludens-1 and -2 regulate apical cell structure and the zonula adherens cytoskeleton in polarized epithelia.
Zonula occludens-1 and -2 regulate apical cell structure and the zonula adherens cytoskeleton in polarized epithelia.
复制标题
DOI：
10.1091/mbc.e11-09-0791
复制
发表时间：
2012-02
影响因子：
3.3
通讯作者：
Anderson JM
中科院分区：
文献类型：
--
作者：
Fanning AS;Van Itallie CM;Anderson JM
ETOC：我们的研究表明，在完全极化的细胞中，ZO蛋白调节与粘连连接相关的连接周围肌动球蛋白环的组装和收缩。黏附连接(AJ)和紧密连接(TJ)的结构和功能都依赖于皮质肌动蛋白细胞骨架。ZO-1和ZO-2蛋白与两种连接类型都具有上下文依赖性相互作用，并直接与F-肌动蛋白和其他细胞骨架蛋白结合，提示ZO-1和-2可能调节细胞连接处的细胞骨架活性。为了解决这一假设，我们建立了稳定的Madin-Darby犬肾脏细胞系，ZO-1和-2都缺失。在ZO-1/-2耗竭的细胞中，细胞旁通透性和TJ蛋白的定位都被破坏。此外，免疫细胞化学和电子显微镜显示与AJ相关的交界处肌动球蛋白环显著扩张。伴随着这些结构变化的是1-磷酸肌球蛋白轻链和Rho激酶1的重新聚集，肌动球蛋白环的收缩，以及顶端结构域的扩张。尽管顶端细胞骨架发生了这些变化，但在细胞极性、AJ蛋白的定位或基础和侧向肌动蛋白细胞骨架的组织结构方面没有可检测到的变化。我们的结论是，ZO蛋白不仅是TJ组装所必需的，而且也是调节顶端细胞骨架的组织和功能活性所必需的，我们推测这些活性与细胞组织和上皮形态发生有关。
ETOC: Our study reveals that ZO proteins in fully polarized cells regulate the assembly and contractility of the perijunctional actomyosin ring associated with the adherens junction. The structure and function of both adherens (AJ) and tight (TJ) junctions are dependent on the cortical actin cytoskeleton. The zonula occludens (ZO)-1 and -2 proteins have context-dependent interactions with both junction types and bind directly to F-actin and other cytoskeletal proteins, suggesting ZO-1 and -2 might regulate cytoskeletal activity at cell junctions. To address this hypothesis, we generated stable Madin-Darby canine kidney cell lines depleted of both ZO-1 and -2. Both paracellular permeability and the localization of TJ proteins are disrupted in ZO-1/-2–depleted cells. In addition, immunocytochemistry and electron microscopy revealed a significant expansion of the perijunctional actomyosin ring associated with the AJ. These structural changes are accompanied by a recruitment of 1-phosphomyosin light chain and Rho kinase 1, contraction of the actomyosin ring, and expansion of the apical domain. Despite these changes in the apical cytoskeleton, there are no detectable changes in cell polarity, localization of AJ proteins, or the organization of the basal and lateral actin cytoskeleton. We conclude that ZO proteins are required not only for TJ assembly but also for regulating the organization and functional activity of the apical cytoskeleton, particularly the perijunctional actomyosin ring, and we speculate that these activities are relevant both to cellular organization and epithelial morphogenesis.