Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.
Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.
Sci Rep. 2018 Jan 9;8(1):219. doi: 10.1038/s41598-017-18640-z.
The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures; most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse.
突触后密度（PSD）是一种电子致密区，包含约 1000 种蛋白质，位于兴奋性突触的突触后膜上，其大小取决于突触强度。PSD95 是 PSD 中的一种丰富的支架蛋白，组装了由神经递质受体、离子通道以及信号和结构蛋白组成的一系列超级复合物。我们使用超分辨率 STED（受激发射损耗）纳米显微镜来确定麻醉小鼠视觉皮层中 PSD95 的大小和形状。在 1 分钟到 6 小时的时间点，对表达 GFP 融合到内源性 PSD95 蛋白的成年 knock-in 小鼠进行成像。超分辨的 PSD95 大组装显示出不同的亚结构；大多数大组装呈环状，有些呈马蹄形或 8 字形，形状连续或由纳米簇组成。在较短的（分钟）时间点，亚结构似乎是稳定的，但在 1 小时后，超过 50%的大组装显示出亚结构的变化。总体而言，这些数据显示了 PSD95 大组装的亚形态，在麻醉小鼠的 6 小时观察期内发生了变化。
