Institute of Biomedical Engineering, School of Medicine and School of Engineering, National Taiwan University, Taipei 106, Taiwan.
Department of Chemical Engineering, School of Engineering, National Taiwan University, Taipei 106, Taiwan.
Proc Natl Acad Sci U S A. 2017 Aug 8;114(32):8568-8573. doi: 10.1073/pnas.1702526114. Epub 2017 Jul 24.
Endogenous electric fields (EFs) are involved in developmental regulation and wound healing. Although the phenomenon is known for more than a century, it is not clear how cells perceive the external EF. Membrane proteins, responding to electrophoretic and electroosmotic forces, have long been proposed as the sensing molecules. However, specific charge modification of surface proteins did not change cell migration motility nor directionality in EFs. Moreover, symmetric alternating current (AC) EF directs cell migration in a frequency-dependent manner. Due to their charge and ability to coalesce, glycolipids are therefore the likely primary EF sensor driving polarization of membrane proteins and intracellular signaling. We demonstrate that detergent-resistant membrane nanodomains, also known as lipid rafts, are the primary response element in EF sensing. The clustering and activation of caveolin and signaling proteins further stabilize raft structure and feed-forward downstream signaling events, such as rho and PI3K activation. Theoretical modeling supports the experimental results and predicts AC frequency-dependent cell and raft migration. Our results establish a fundamental mechanism for cell electrosensing and provide a role in lipid raft mechanotransduction.
内源性电场 (EFs) 参与发育调控和伤口愈合。尽管这一现象已经存在了一个多世纪,但细胞如何感知外部 EF 还不清楚。膜蛋白对电泳和电渗流的反应,长期以来一直被认为是感应分子。然而,表面蛋白的特定电荷修饰并没有改变细胞在 EF 中的迁移运动性或方向性。此外,对称交流 (AC) EF 以频率依赖的方式引导细胞迁移。由于它们的电荷和凝聚能力,糖脂因此很可能是驱动膜蛋白极化和细胞内信号转导的主要 EF 传感器。我们证明,去污剂抗性膜纳米区,也称为脂筏,是 EF 感应的主要反应元件。窖蛋白和信号蛋白的聚类和激活进一步稳定了筏结构,并反馈下游信号事件,如 rho 和 PI3K 的激活。理论模型支持实验结果,并预测了 AC 频率依赖性的细胞和筏迁移。我们的结果为细胞电感应建立了一个基本机制,并为脂筏机械转导提供了一个作用。