Managing the dark:light transition by dynamic micro-compartmentalization in plant mitochondria

线粒体是所有复杂生命的共同点。它们作为大量ATP的来源，为需要能量的细胞过程提供燃料，从而允许运动，生长和发育。然而，在植物中，这种情况随着日出而改变。然后，光合作用取代呼吸作用成为主要的生物能量过程，线粒体运作的生理环境经历了深刻的转变。光合作用急剧改变细胞代谢产物和辅因子库，并增加局部氧水平。线粒体机制不仅维持改变的细胞状态，而且支持有效的光合作用。这需要线粒体功能的积极再奉献，并意味着线粒体与叶绿体的严格协调。此外，它还包括植物特有的光与暗之间的周期性操作过渡。在拟议的研究中，我们将通过分析蛋白质在黎明时的相互作用的动态，来解决线粒体功能在暗到光的转换过程中的快速适应是如何在绿色植物组织中编排的问题。酶与蛋白质复合物的结合导致微区室的形成，其具有减小的扩散距离并增加途径的周转率。它还限制了分支或竞争反应造成的中间产物损失，因此提高了途径的代谢效率。对于哺乳动物和酵母线粒体蛋白质：基质酶的蛋白质相互作用与潜在的影响，调节已经显示。在以前的研究中，在植物中检测到类似的相互作用。为了评估在何种程度上动态蛋白质：蛋白质相互作用的影响，植物线粒体代谢的调整，在黎明，我们在这里提出了一个组合的生化和遗传的方法，使广泛的，但（部分）详细的观点对这个话题。功能分析将用于深入了解黎明前后线粒体的代谢状态，并将使蛋白质相互作用模式的变化与线粒体生理状态的改变直接相关。这项研究将与其他两个项目一起作为植物线粒体的一部分提出新的光倡议，这将为光合生物中调节线粒体功能的机制提供新的深入见解。

Mitochondria are common to all complex life. They host respiration as the source of the large amounts of ATP that are necessary to fuel energy-demanding cellular processes allowing movement, growth, and development. In plants, however, this situation changes with sunrise. Then photosynthesis takes over from respiration as the dominating bioenergetic process, and the physiological environment in which the mitochondria operate undergoes a profound transition. Photosynthesis drastically alters the cellular metabolite and cofactor pools and increases local oxygen levels. The mitochondrial machinery then not only sustains an altered cellular status, but supports efficient photosynthesis. This requires active re-dedication of mitochondrial function and implies strict coordination of the mitochondria with the chloroplasts. Moreover, it includes a periodic operational transition between light and dark that is unique to plants. In the proposed research, we will address the question how the rapid acclimation of mitochondrial functions during dark-to-light transitions is choreographed in green plant tissues by analysing the dynamics of protein:protein interactions at dawn. Association of enzymes to protein complexes leads to the formation of micro-compartments with reduced diffusion distances and increases turnover rates of pathways. It also limits losses of intermediates by branching or competing reactions and, as such, increases metabolic efficiency of pathways. For mammalian and yeast mitochondria protein:protein interactions of matrix enzymes with potential implications for regulation have already been shown. Similar interactions in plants were detected in a previous study. To assess to which extent dynamic protein:protein interactions impact on the adjustment of plant mitochondrial metabolism at dawn, we here propose a combination of biochemical and genetic approaches which enables a broad, yet (in parts) detailed view on this topic. Functional assays will be used to gain insight into the metabolic state of mitochondria before and after dawn and will enable direct correlation of changes in protein:protein interaction patterns with alterations of the physiological status of the mitochondria.Together with two other projects proposed as part of the Plant Mitochondria in a New Light initiative, this research will provide novel depth of insight into the mechanisms regulating mitochondrial function in photosynthetic organisms.