线粒体去极化和线粒体自噬吞噬作用的冷冻电镜可视化
cryo-ET visualization of mitochondrial depolarization and mitophagic engulfment.
作者信息
Rose Kevin, Herrmann Eric, Kakudji Eve, Lizarrondo Javier, Celebi A Yasemin, Wilfling Florian, Lewis Samantha C, Hurley James H
机构信息
Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA.
出版信息
bioRxiv. 2025 Mar 25:2025.03.24.645001. doi: 10.1101/2025.03.24.645001.
Defective mitochondrial quality control in response to loss of mitochondrial membrane polarization is implicated in Parkinson's disease by mutations in and . Application of cryo-electron tomography (cryo-ET) made it possible to visualize the consequences of mitochondrial depolarization at higher resolution than heretofore attainable. Parkin-expressing U2OS cells were treated with the depolarizing agents oligomycin and antimycin A (OA), subjected to cryo-FIB milling, and mitochondrial structure was characterized by cryo-ET. Phagophores were visualized in association with mitochondrial fragments. Bridge-like lipid transporter (BLTP) densities potentially corresponding to ATG2A were seen connected to mitophagic phagophores. Mitochondria in OA-treated cells were fragmented and devoid of matrix calcium phosphate crystals. The intermembrane gap of cristae was narrowed and the intermembrane volume reduced, and some fragments were devoid of cristae. A subpopulation of ATP synthases re-localized from cristae to the inner boundary membrane (IBM) apposed to the outer membrane (OMM). The structure of the dome-shaped prohibitin complex, a dodecamer of PHB1-PHB2 dimers, was determined by sub-tomogram averaging in untreated and treated cells and found to exist in open and closed conformations, with the closed conformation is enriched by OA treatment. These findings provide a set of native snapshots of the manifold nano-structural consequences of mitochondrial depolarization and provide a baseline for future dissection of Parkin-dependent mitophagy.
线粒体膜去极化时线粒体质量控制缺陷与帕金森病相关,这一点由[基因名称1]和[基因名称2]中的突变所表明。低温电子断层扫描(cryo-ET)的应用使得以比以往更高的分辨率可视化线粒体去极化的后果成为可能。用去极化剂寡霉素和抗霉素A(OA)处理表达帕金蛋白的U2OS细胞,进行低温聚焦离子束铣削,并通过低温电子断层扫描对线粒体结构进行表征。吞噬泡与线粒体片段相关联。可见潜在对应于ATG2A的桥状脂质转运蛋白(BLTP)密度与线粒体自噬吞噬泡相连。经OA处理的细胞中的线粒体发生片段化,且没有基质磷酸钙晶体。嵴的膜间隙变窄,膜间体积减小,一些片段没有嵴。一部分ATP合酶从嵴重新定位到与外膜(OMM)相对的内边界膜(IBM)。通过在未处理和处理的细胞中进行亚断层平均确定了由PHB1-PHB2二聚体组成的十二聚体圆顶形抑制素复合物的结构,发现其以开放和封闭构象存在,封闭构象在OA处理后富集。这些发现提供了一组线粒体去极化多种纳米结构后果的原始快照,并为未来剖析帕金蛋白依赖性线粒体自噬提供了基线。