Farley M M, Swulius M T, Waxham M N
The Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States; Graduate School of Biomedical Science, University of Texas Health Science Center at Houston, Houston, TX 77030, United States.
The Department of Neurobiology and Anatomy, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, United States.
Neuroscience. 2015 Sep 24;304:286-301. doi: 10.1016/j.neuroscience.2015.07.062. Epub 2015 Jul 26.
Electron tomography and immunogold labeling were used to analyze similarities and differences in the morphology and protein composition of postsynaptic densities (PSDs) isolated from adult rat cerebella, hippocampi, and cortices. There were similarities in physical dimensions and gross morphology between cortical, hippocampal and most cerebellar PSDs, although the morphology among cerebellar PSDs could be categorized into three distinct groups. The majority of cerebellar PSDs were composed of dense regions of protein, similar to cortical and hippocampal PSDs, while others were either composed of granular or lattice-like protein regions. Significant differences were found in protein composition and organization across PSDs from the different brain regions. The signaling protein, βCaMKII, was found to be a major component of each PSD type and was more abundant than αCaMKII in both hippocampal and cerebellar PSDs. The scaffold molecule PSD-95, a major component of cortical PSDs, was found absent in a fraction of cerebellar PSDs and when present was clustered in its distribution. In contrast, immunogold labeling for the proteasome was significantly more abundant in cerebellar and hippocampal PSDs than cortical PSDs. Together, these results indicate that PSDs exhibit remarkable diversity in their composition and morphology, presumably as a reflection of the unique functional demands placed on different synapses.
采用电子断层扫描和免疫金标记技术，分析从成年大鼠小脑、海马体和皮质中分离出的突触后致密物（PSD）在形态和蛋白质组成上的异同。皮质、海马体和大多数小脑PSD在物理尺寸和大体形态上存在相似性，尽管小脑PSD的形态可分为三个不同的组。大多数小脑PSD由蛋白质致密区域组成，类似于皮质和海马体PSD，而其他的则由颗粒状或晶格状蛋白质区域组成。在来自不同脑区的PSD中，发现蛋白质组成和组织存在显著差异。信号蛋白βCaMKII被发现是每种PSD类型的主要成分，并且在海马体和小脑PSD中比αCaMKII更丰富。支架分子PSD - 95是皮质PSD的主要成分，在一部分小脑PSD中未发现，而当存在时其分布呈聚集状。相比之下，蛋白酶体的免疫金标记在小脑和海马体PSD中比皮质PSD中明显更丰富。总之，这些结果表明PSD在其组成和形态上表现出显著的多样性，大概反映了不同突触所面临的独特功能需求。
