Anionic phospholipids can confer a net negative charge to biological membranes. This surface charge generates an electrical field that serves to recruit extrinsic cationic proteins, can alter the disposition of transmembrane proteins and causes the local accumulation of soluble counterions, altering the local pH and the concentration of physiologically important ions like calcium. Because the phospholipid composition of the different organellar membranes varies, their surface charge is similarly expected to diverge. Yet, despite the important functional implications, remarkably little is known about the electrostatic properties of the individual organellar membranes. We therefore designed and implemented approaches to estimate the surface charge of the cytosolic membrane of various organelles in situ in intact cells. Our data indicate that the inner leaflet of the plasma membrane is most negative, with a surface potential of approximately -35 mV, followed by the Golgi complex > lysosomes > mitochondria ≈ peroxisomes > the endoplasmic reticulum, in decreasing order.

阴离子磷脂可以赋予生物膜净负电荷。这种表面电荷产生一个电场，用于募集外源性阳离子蛋白，可以改变跨膜蛋白的分布，并导致可溶性反离子的局部积累，改变局部 pH 值和生理学重要离子（如钙）的浓度。由于不同细胞器膜的磷脂组成各不相同，因此它们的表面电荷同样预计会发散。然而，尽管具有重要的功能意义，但对单个细胞器膜的静电特性知之甚少。因此，我们设计并实施了原位估计各种细胞器胞质膜表面电荷的方法在完整的细胞中。我们的数据表明质膜的内小叶最负，表面电位约为 -35 mV，其次是高尔基复合体 > 溶酶体 > 线粒体 ≈ 过氧化物酶体 > 内质网，依次递减。