Meeusen Shelly L, Nunnari Jodi
Department of Molecular and Cellular Biology, University of California Davis, USA.
Methods Mol Biol. 2007;372:461-6. doi: 10.1007/978-1-59745-365-3_32.
The field of mitochondrial dynamics has received a great deal of attention as a result of a number of studies linking mitochondrial fission and fusion machinery to apoptosis. Specifically, elevated levels of mitochondrial fission or compromised mitochondrial fusion can sensitize cells to apoptotic stimuli. Conversely, stimulation of mitochondrial fusion can render cells resistant to apoptotic stimuli. In addition, the machinery involved in fission and fusion has been spatially linked to Bax, a pro-apoptotic protein. However, the mechanistic implications of interactions between the machinery of mitochondrial fission and fusion and apoptotic effectors are largely unknown. Our understanding of the pathways of mitochondrial fission and fusion have come from genetic studies coupled with direct observation of both fission and fusion components and mitochondrial organelle morphology and behavior in vivo in Saccharomyces cerevisiae. These approaches have identified the key players in both mitochondrial fission and fusion and have generated good models for their roles in mitochondrial dynamics. However, the lack of in vitro systems for studying these processes has impeded a deeper investigation of the mechanism. We have recapitulated the process of mitochondrial fusion in vitro (5). Using this in vitro fusion assay, we have separated outer mitochondrial membrane fusion from inner and identified the mechanistic requirements for each step.
由于多项研究将线粒体分裂和融合机制与细胞凋亡联系起来，线粒体动力学领域受到了广泛关注。具体而言，线粒体分裂水平升高或线粒体融合受损会使细胞对凋亡刺激敏感。相反，刺激线粒体融合可使细胞对凋亡刺激产生抗性。此外，参与分裂和融合的机制在空间上与促凋亡蛋白Bax相关联。然而，线粒体分裂和融合机制与凋亡效应器之间相互作用的机制意义在很大程度上尚不清楚。我们对线粒体分裂和融合途径的理解来自于遗传学研究，以及对酿酒酵母体内分裂和融合成分以及线粒体细胞器形态和行为的直接观察。这些方法已经确定了线粒体分裂和融合的关键参与者，并为它们在线粒体动力学中的作用建立了良好的模型。然而，缺乏用于研究这些过程的体外系统阻碍了对其机制的更深入研究。我们已经在体外重现了线粒体融合过程（5）。利用这种体外融合测定法，我们将线粒体外膜融合与内膜融合分开，并确定了每个步骤的机制要求。
