State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, People's Republic of China.
College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.
Microbiol Spectr. 2023 Jun 15;11(3):e0004023. doi: 10.1128/spectrum.00040-23. Epub 2023 May 8.
Metabolism associated with energy production is highly compartmentalized in eukaryotic cells. During this process, transporters that move metabolites across organelle membranes play pivotal roles. The highly conserved ADP/ATP carrier (AAC) involved in ATP and ADP exchange between the mitochondria and cytoplasm is key to linking the metabolic activities in these 2 compartments. The ATP produced in mitochondria can be exchanged with cytoplasmic ADP by AAC, thus satisfying the energy needs in the cytoplasm. Toxoplasma gondii is an obligate intracellular parasite with a wide range of hosts. Previous studies have shown that mitochondrial metabolism helps to parasitize diverse host cells. Here, we identified 2 putative mitochondria ADP/ATP carriers in with significant sequence similarity to known AACs from other eukaryotes. We examined the ATP transport function of AACs by expressing them in Escherichia coli cells and found that only AAC1 had ATP transport activity. Moreover, knockdown of AAC1 caused severe growth defects of parasites and heterologous expression of mouse ANT2 in the AAC1 depletion mutant restored its growth, revealing its importance for parasite growth. These results verified that AAC1 functions as the mitochondrial ADP/ATP carrier in T. gondii and the functional studies demonstrated the importance of AAC1 for tachyzoites growth. T. gondii has an efficient and flexible energy metabolism system to meet different growth needs. ATP is an energy-carrying molecule and needs to be exchanged between organelles with the assistance of transporters. However, the function of AACs has yet to be characterized. Here, we identified 2 putative AACs of T. gondii and verified that only AAC1 had ATP transport activity with expression in the intact E. coli cells. Detailed analyses found that AAC1 is critical for the growth of tachyzoites and AAC2 is dispensable. Moreover, complementation with mouse ANT2 restored the growth speed of iAAC1, further suggesting AAC1 functions as a mitochondrial ADP/ATP carrier. Our research demonstrated the importance of AAC1 for tachyzoites growth.
真核细胞中与能量产生相关的代谢是高度分隔的。在此过程中，跨细胞器膜运输代谢物的转运蛋白起着关键作用。高度保守的 ADP/ATP 载体（AAC）参与线粒体和细胞质之间的 ATP 和 ADP 交换，是连接这两个隔室代谢活动的关键。在线粒体中产生的 ATP 可以通过 AAC 与细胞质中的 ADP 交换，从而满足细胞质中的能量需求。刚地弓形虫是一种广泛宿主的专性细胞内寄生虫。先前的研究表明，线粒体代谢有助于寄生多种宿主细胞。在这里，我们在 中鉴定了 2 种具有与其他真核生物已知 AAC 显著序列相似性的推定线粒体 ADP/ATP 载体。我们通过在大肠杆菌细胞中表达它们来检查 AAC 的 ATP 转运功能，发现只有 AAC1 具有 ATP 转运活性。此外，敲低 AAC1 导致寄生虫生长严重缺陷，并且在 AAC1 耗竭突变体中异源表达小鼠 ANT2 恢复了其生长，表明其对寄生虫生长的重要性。这些结果验证了 AAC1 在 T. gondii 中作为线粒体 ADP/ATP 载体的功能，并且功能研究表明 AAC1 对速殖子生长的重要性。T. gondii 具有高效灵活的能量代谢系统，以满足不同的生长需求。ATP 是一种携带能量的分子，需要在转运蛋白的协助下在细胞器之间交换。然而，AACs 的功能尚未得到表征。在这里，我们鉴定了 T. gondii 的 2 种推定 AAC，并通过在完整的大肠杆菌细胞中表达验证了只有 AAC1 具有 ATP 转运活性。详细分析发现 AAC1 对速殖子的生长至关重要，而 AAC2 则是可有可无的。此外，用小鼠 ANT2 进行互补恢复了 iAAC1 的生长速度，进一步表明 AAC1 作为线粒体 ADP/ATP 载体发挥作用。我们的研究表明 AAC1 对速殖子生长的重要性。
