School of Life Sciences, Zhengzhou University, Zhengzhou 450001, China.
College of Public Health, Zhengzhou University, Zhengzhou 450001, China.
Biochim Biophys Acta Biomembr. 2018 May;1860(5):1143-1151. doi: 10.1016/j.bbamem.2018.02.009. Epub 2018 Feb 8.
The membrane skeleton forms a scaffold on the cytoplasmic side of the plasma membrane. The erythrocyte membrane represents an archetype of such structural organization. It has been documented that a similar membrane skeleton also exits in the Golgi complex. It has been previously shown that βII spectrin and ankyrin G are localized at the lateral membrane of human bronchial epithelial cells. Here we show that protein 4.1N is also located at the lateral membrane where it associates E-cadherin, β-catenin and βII spectrin. Importantly, depletion of 4.1N by RNAi in human bronchial epithelial cells resulted in decreased height of lateral membrane, which was reversed following re-expression of mouse 4.1N. Furthermore, although the initial phase of lateral membrane biogenesis proceeded normally in 4.1N-depleted cells, the final height of the lateral membrane of 4.1N-depleted cells was shorter compared to that of control cells. Our findings together with previous findings imply that 4.1N, βII spectrin and ankyrin G are structural components of the lateral membrane skeleton and that this skeleton plays an essential role in the assembly of a fully functional lateral membrane.
细胞膜骨架在质膜的细胞质侧形成支架。红细胞膜是这种结构组织的原型。有文献证明高尔基体复合物中也存在类似的膜骨架。先前的研究表明βII spectrin 和锚蛋白 G 定位于人支气管上皮细胞的侧膜。在这里，我们发现蛋白 4.1N 也位于侧膜，与 E-钙黏蛋白、β-连环蛋白和βII spectrin 相关。重要的是，在人支气管上皮细胞中用 RNAi 耗尽 4.1N 会导致侧膜高度降低，而在用鼠 4.1N 重新表达后则会逆转。此外，尽管 4.1N 耗尽细胞中侧膜生物发生的初始阶段正常进行，但与对照细胞相比，4.1N 耗尽细胞的侧膜最终高度更短。我们的研究结果与先前的研究结果表明，4.1N、βII spectrin 和锚蛋白 G 是侧膜骨架的结构成分，该骨架在完全功能性侧膜的组装中发挥重要作用。
