近日，美国加州大学伯克利分校Ke Xu及其课题组通过多维单分子和超高分辨率显微镜，实现细胞膜纳米尺度下扩散异质性的检测。该研究于2020年10月21日在线发表于国际一流学术期刊《美国化学会志》。

Title: Probing Nanoscale Diffusional Heterogeneities in Cellular Membranes through Multidimensional Single-Molecule and Super-Resolution Microscopy

Author: Rui Yan, Kun Chen, Ke Xu

Issue&Volume: October 21, 2020

Abstract: Diffusion properties notably determine the behavior of biomembranes. Here we report the concurrent nanoscale fine-mapping of membrane topography, diffusivity, and packing order in live mammalian cells through a synergy of single-molecule and super-resolution methods. By identifying a bright, lipophilic fluorescence turn-on probe that enables sustained single-molecule imaging of cellular membranes under stroboscopic excitation, we accumulate the positions and transient displacements of >106 probe molecules to achieve super-resolution topography and diffusivity mapping. We thus determine a trend that the membrane diffusivity drops with increased lipid packing order when comparing the endoplasmic reticulum (ER) membrane, plasma membrane, and nanodomains induced by cholera toxin B. Utilizing our nanoscale mapping capability, we further unveil reduced diffusivity in the ER membrane at ER–plasma membrane contact sites. By next integrating spectrally resolved single-molecule imaging, we show that this localized diffusion slowdown is not due to altered lipid packing order but may instead be attributed to local protein crowding. Our integrated multidimensional single-molecule approach thus unveils and differentiates between nanoscale diffusional heterogeneities of different origins in live-cell membranes.

DOI: 10.1021/jacs.0c08426

Source: https://pubs.acs.org/doi/10.1021/jacs.0c08426