MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine , University of Oxford , Oxford OX3 9DS , U.K.
Faculty of Pharmacy , University of Ljubljana , Askerceva cesta 7 , 1000 Ljubljana , Slovenia.
J Phys Chem B. 2020 Feb 27;124(8):1487-1494. doi: 10.1021/acs.jpcb.0c00445. Epub 2020 Feb 18.
Membrane models have allowed for precise study of the plasma membrane's biophysical properties, helping to unravel both structural and dynamic motifs within cell biology. Freestanding and supported bilayer systems are popular models to reconstitute membrane-related processes. Although it is well-known that each have their advantages and limitations, comprehensive comparison of their biophysical properties is still lacking. Here, we compare the diffusion and lipid packing in giant unilamellar vesicles, planar and spherical supported membranes, and cell-derived giant plasma membrane vesicles. We apply florescence correlation spectroscopy (FCS), spectral imaging, and super-resolution stimulated emission depletion FCS to study the diffusivity, lipid packing, and nanoscale architecture of these membrane systems, respectively. Our data show that lipid packing and diffusivity is tightly correlated in freestanding bilayers. However, nanoscale interactions in the supported bilayers cause deviation from this correlation. These data are essential to develop accurate theoretical models of the plasma membrane and will serve as a guideline for suitable model selection in future studies to reconstitute biological processes.
膜模型允许对质膜的生物物理特性进行精确研究，有助于揭示细胞生物学中的结构和动态特征。独立的和支撑的双层系统是用来重建与膜相关过程的流行模型。尽管人们已经知道每种模型都有其优点和局限性，但对它们的生物物理特性的全面比较仍然缺乏。在这里，我们比较了巨单层囊泡、平面和球形支撑膜以及细胞衍生的巨质膜囊泡中的扩散和脂质堆积。我们应用荧光相关光谱（FCS）、光谱成像和超分辨率受激发射损耗 FCS 分别研究这些膜系统的扩散性、脂质堆积和纳米级结构。我们的数据表明，在独立双层中，脂质堆积和扩散性紧密相关。然而，支撑双层中的纳米级相互作用导致与该相关性的偏离。这些数据对于开发质膜的精确理论模型至关重要，并将作为未来研究中重建生物过程的合适模型选择的指南。
