Angert Isaac, Karuka Siddarth Reddy, Mansky Louis M, Mueller Joachim D
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
Institute of Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA.
Sci Adv. 2022 Aug 19;8(33):eabj3236. doi: 10.1126/sciadv.abj3236.
The cell cortex plays a crucial role in cell mechanics, signaling, and development. However, little is known about the influence of the cortical meshwork on the spatial distribution of cytoplasmic biomolecules. Here, we describe a fluorescence microscopy method with the capacity to infer the intracellular distribution of labeled biomolecules with subresolution accuracy. Unexpectedly, we find that RNA binding proteins are partially excluded from the cytoplasmic volume adjacent to the plasma membrane that corresponds to the actin cortex. Complementary diffusion measurements of RNA-protein complexes suggest that a rudimentary model based on excluded volume interactions can explain this partitioning effect. Our results suggest the actin cortex meshwork may play a role in regulating the biomolecular content of the volume immediately adjacent to the plasma membrane.
细胞皮层在细胞力学、信号传导和发育过程中发挥着关键作用。然而，关于皮层网络对细胞质生物分子空间分布的影响却知之甚少。在此，我们描述了一种荧光显微镜方法，该方法能够以亚分辨率精度推断标记生物分子的细胞内分布。出乎意料的是，我们发现RNA结合蛋白部分被排除在与肌动蛋白皮层相对应的质膜附近的细胞质区域之外。RNA-蛋白质复合物的补充扩散测量表明，基于排阻体积相互作用的基本模型可以解释这种分配效应。我们的结果表明，肌动蛋白皮层网络可能在调节紧邻质膜区域的生物分子含量方面发挥作用。
