Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.
Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
Sci Rep. 2017 Mar 30;7:45474. doi: 10.1038/srep45474.
Within mitochondria, the ability to produce energy relies upon the architectural hallmarks of double membranes and cristae invaginations. Herein, we describe novel features of mitochondrial cristae structure, which correspond to the energetic state of the organelle. In concordance with high-energy demand, mitochondria of Drosophila indirect flight muscle exhibited extensive intra-mitochondrial membrane switches between densely packed lamellar cristae that resulted in a spiral-like cristae network and allowed for bidirectional matrix confluency. This highly interconnected architecture is expected to allow rapid equilibration of membrane potential and biomolecules across integrated regions. In addition, mutant flies with mtDNA replication defect and an accelerated aging phenotype accumulated mitochondria that contained subsections of swirling membrane alongside normal cristae. The swirling membrane had impaired energy production capacity as measured by protein composition and function. Furthermore, mitochondrial fusion and fission dynamics were affected in the prematurely aged flies. Interestingly, the normal cristae that remained in the mitochondria with swirling membranes maintained acceptable function that camouflaged them from quality control elimination. Overall, structural features of mitochondrial cristae were described in three-dimension from serial section electron tomographic analysis which reflect energetic state and mtDNA-mediated aging.
在线粒体中，产生能量的能力依赖于双层膜和嵴内陷的结构特征。在这里，我们描述了线粒体嵴结构的新特征，这些特征与细胞器的能量状态相对应。与高能需求一致，果蝇间接飞行肌的线粒体表现出密集堆积的板层嵴之间广泛的线粒体内部膜开关，导致螺旋状嵴网络，并允许基质双向融合。这种高度互联的结构预计可以允许快速平衡跨整合区域的膜电位和生物分子。此外，具有 mtDNA 复制缺陷和加速衰老表型的突变体果蝇积累了含有旋转膜片段的线粒体，同时还保留了正常的嵴。旋转膜的能量产生能力受损，这可以通过蛋白质组成和功能来衡量。此外，线粒体融合和裂变动力学在过早衰老的果蝇中受到影响。有趣的是，在含有旋转膜的线粒体中保留的正常嵴保持了可接受的功能，这掩盖了它们免受质量控制的消除。总的来说，通过连续切片电子断层摄影分析对线粒体嵴的三维结构特征进行了描述，这些特征反映了能量状态和 mtDNA 介导的衰老。
