Electron Microscopic Analysis of a Spherical Mitochondrial Structure
Electron Microscopic Analysis of a Spherical Mitochondrial Structure
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DOI：
10.1074/jbc.m112.413674
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发表时间：
2012-12-07
影响因子：
4.8
通讯作者：
Yin, Xiao-Ming
中科院分区：
文献类型：
--
作者：
Ding, Wen-Xing;Li, Min;Yin, Xiao-Ming
线粒体经历动态的结构改变以满足不断变化的需求并维持体内平衡。我们在这里报告一个新的线粒体结构。常规透射电子显微镜检查用羰基氰间氯苯腙（CCCP），线粒体解偶联剂处理的小鼠胚胎成纤维细胞，发现超过一半的线粒体呈环形或C形形态。这些线粒体中的许多似乎已经吞噬了各种胞质组分。通过单个线粒体的连续切片表明，它们形成了一个球状结构，内部管腔被膜包围，并含有胞质物质。值得注意的是，管腔通过一个小开口连接到外部细胞质。线粒体球体的电子断层扫描重建证明了膜拓扑结构，并证实了这种线粒体结构的囊泡配置。外周和管腔由外膜限定，外膜与内膜排列。基质和嵴被保留，但分布不均匀，在管腔开口附近保留较少。线粒体球状体的形成似乎是对线粒体氧化损伤的反应，与线粒体自噬无关。因此，线粒体球状体的结构特征代表了一种新的线粒体动力学。
Mitochondria undergo dynamic structural alterations to meet changing needs and to maintain homeostasis. We report here a novel mitochondrial structure. Conventional transmission electron microscopic examination of murine embryonic fibroblasts treated with carbonyl cyanide m-chlorophenylhydrazone (CCCP), a mitochondrial uncoupler, found that more than half of the mitochondria presented a ring-shaped or C-shaped morphology. Many of these mitochondria seemed to have engulfed various cytosolic components. Serial sections through individual mitochondria indicated that they formed a ball-like structure with an internal lumen surrounded by the membranes and containing cytosolic materials. Notably, the lumen was connected to the external cytoplasm through a small opening. Electron tomographic reconstruction of the mitochondrial spheroids demonstrated the membrane topology and confirmed the vesicular configuration of this mitochondrial structure. The outside periphery and the lumen were defined by the outer membranes, which were lined with the inner membranes. Matrix and cristae were retained but distributed unevenly with less being kept near the luminal opening. Mitochondrial spheroids seem to form in response to oxidative mitochondrial damage independently of mitophagy. The structural features of the mitochondrial spheroids thus represent a novel mitochondrial dynamics.